Program

Metasurfaces, as two-dimensional arrays of
subwavelength engineered meta-atoms, provide powerful
control over electromagnetic waves through spatial
modulation of amplitude, phase, polarisation, and
surface
impedance. Compared with conventional bulk
metamaterials,
metasurfaces offer a lower-profile, more
fabrication-friendly
platform while retaining strong wavefront-engineering
capabilities, enabling applications such as beam
steering,
focusing, polarisation control, holography, and antenna
miniaturisation. In antenna applications, metasurfaces
have
progressed from reflectarray or lens structures to
radiating
apertures, forming metasurface antennas capable of
guiding,
modulating, and radiating electromagnetic waves with
high
design flexibility. However, passive metasurfaces are
inherently limited to fixed responses after fabrication,
motivating extensive research into tunable and
reconfigurable
metasurfaces based on electrical, optical, mechanical,
liquidcrystal,
semiconductor, and phase-change-material tuning
mechanisms. Although these approaches have enabled
dynamic electromagnetic control, scalable implementation
remains constrained by biasing complexity, fabrication
cost,
power consumption, and the need to individually address
large
numbers of unit cells.

In 5G and beyond 5G era, the growing demands for high
data transmission rates in communication systems and
high resolution in radar imaging pose strict
requirements on millimeter-wave phase shifters.
Specifically, wide bandwidth, precise phase control, and
high amplitude consistency are essential for ensuring
excellent beamforming quality and scanning accuracy. In
this way, passive switched-type MMIC phase shifters have
emerged as a promising solution, featuring zero DC power
consumption and low-cost calibration. However, in the
conventional direct-cascading architecture for multi-bit
designs, inter-stage mismatch and load-pulling effects
severely restrict the operational bandwidth and degrade
the phase and amplitude accuracy. In this talk, some
recent research on new phase-control theories and
path-switching mechanisms for mmW switched-type phase
shifters in our group will be presented. These
strategies are expected to provide an architecture-level
solution for mmW multi-bit phase shifters in wireless
communication.

To address the 3 dB polarization mismatch loss of
linearly polarized antennas when receiving circularly
polarized satellite signals, this work proposes an
end-fire, high-gain circularly polarized mobile phone
antenna with wide beamwidth. The antenna comprises three
elements: a patch antenna integrated with the camera
decoration (Deco), a frame antenna located at the top of
the phone, and choke structures embedded in the side
frames. The patch and frame antennas generate parallel
electric and magnetic currents, respectively, whose
combination produces end-fire left-handed circular
polarization (LHCP). The antenna operates at a center
frequency of 1.7 GHz with a bandwidth of 20 MHz. It
features high gain and wide beamwidth, achieving a
minimum LHCP gain higher than −5 dBic within a beam
range exceeding a 90° cone angle across the operating
band.

This paper presents a 300 GHz broadband
power-reconfigurable load-modulated balanced amplifier
(PR-LMBA) for broadband sub-terahertz applications. The
proposed architecture leverages intrinsic load
modulation within a balanced topology to realize
dual-mode power operation without employing RF switches
or reconfigurable matching networks. Implemented in a
0.13-um SiGe BiCMOS technology, the PR-LMBA achieves a
peak small-signal gain of 19.4 dB with a 3-dB bandwidth
of 62 GHz (246-308 GHz). In high-power mode, a maximum
output power of 11.4 dBm and a peak power-added
efficiency (PAE) of 2.3% are obtained. In low-power
mode, the amplifier provides 4.7 dBm output power with
1.89% PAE, corresponding to a 6.3 dB reconfigurable
power range.

By exploiting the intrinsic multiple resonant modes of
a 6th-order LC resonator, a triple-band wave-based
oscillator is designed. The LC resonator consists of two
units of left-handed transmission LC network ended with
parallel-tuned LC resonator, and a cross-coupled
switching transistor pair is used to start up the
oscillation. Two pairs of varactors are used for band
tuning and switching. The proposed oscillator has been
implemented with the tsmc 0.18 µm 1P6M CMOS technology
and the core power consumption is 3.735 mW at the dc
drain-source bias of 0.75 V. The VCO can generate
differential signals in the frequency range of 8.04 –
8.68 GHz, 5.82 – 6.15 GHz, and 3.68 – 4.08 GHz. The die
area of the triple-band oscillator is 0.568 × 1.189 mm2.

This paper presents a band-reconfigurable low-noise
amplifier (LNA) that utilizing transformer-based
magnetic coupling technique. It consists of
source-degenerated cascode amplifier integrated with a
tunable magnetic coupling network. By manipulating the
amplitude and phase of the voltage ratio(β), the
position of the transmission zero can be dynamically
adjusted, enabling flexible tuning of bandwidth.
Simulation results demonstrate that the 3-dB bandwidths
range from 15.64 to 23.55 GHz and from 18.35 to 31.38
GHz, with corresponding gains of 16.84 dB and 16.98 dB,
respectively.

This paper presents the design and implementation of a
250-W S-band Class-B solid-state power amplifier (SSPA)
module based on the Ampleon BLC2425M10LS250 laterally
diffused metal-oxide-semiconductor (LDMOS) transistor.
Stepped-impedance microstrip matching networks are
employed to achieve broadband impedance matching over
2.4-2.6 GHz. The amplifier is measured under pulsed
operation with a 10% duty cycle and a 100-μs pulse
period. Measured results demonstrate that the proposed
module delivers 53.69-53.98 dBm (233-250 W) output
power, 14.0-14.4 dB power gain, 66.5%-75.8% drain
efficiency, and 63.6%-72.5% power-added efficiency
across the operating band. In addition, a
high-efficiency power-combining scheme is proposed to
facilitate future kW-class industrial microwave systems.

This paper presents an energy-efficient
reconfigurable Bluetooth Low Energy (BLE) RF receiver
front-end based on a mixer-first architecture for
Internet-of
Things (IoT) applications. To eliminate the hardware
redundancy and high cost associated with conventional
designs
using separate wake-up receiver (WuRX) and main receiver
(RX) front-ends, the proposed architecture enables full
hardware reuse between two parallel operating modes by
reconfiguring the core transimpedance amplifier (TIA) to
operate either as a linear amplifier or as a nonlinear
active
rectifier. The mixer-first architecture facilitates
on-chip
channel selection while reducing power consumption.
Fabricated in a TSMC 28-nm CMOS process, the prototype
consumes 0.2 mW in RX mode and achieves a minimum power
consumption of 30 μW in non-duty-cycled WuRX mode. The
measured input reflection coefficient, S11, is below -10
dB in
both modes across the target frequency band. In WuRX
mode,
the front-end achieves a noise figure of approximately
21 dB
over the signal bandwidth of interest. Based on the
classical RF
sensitivity calculation, the overall WuRX system is
expected to
achieve a receiving sensitivity better than -90 dBm at a
data
rate of 100 kbps. This work provides a low-cost, highly
integrated RF front-end solution for BLE IoT terminals.

While the global commercialization of the
fifth-generation (5G) wireless communications is
gradually taking off, there is already significant
interest in the next generation of wireless
communications. 6G scheduled to be launched in 2030,
will provide a Tbps data rate, microsecond latency, and
almost unlimited bandwidth to the connectivity of
numerous mobile and intelligent networks. Antennas and
metasurfaces are ubiquitous and indispensable components
for generating and manipulating electromagnetic (EM)
waves. In this talk, I will share the development and
design of the space-time metasurface antenna that can
control all fundamental properties of EM waves. The
space-time metasurface antenna can further facilitate
information manipulation, which can fundamentally
simplify the architecture of information transmitter
systems. The unparalleled wave and information
manipulation capabilities of the metasurface antenna
will spark a surge of applications from next-generation
wireless systems, cognitive sensing, to imaging.

A phase-dispersive conformal metamaterial for broadband
electromagnetic (EM) backscattering enhancement is
presented. The metamaterial comprises two layers of LC
resonant structures to achieve broadband
phase-dispersive characteristics. To enable a conformal
design, the first layer employs a low-profile dielectric
substrate with excellent flexibility, while the second
layer is conformally attached to the target surface
using an insertion-based method. The metamaterial is
designed for backscattering enhancement, and a prototype
was fabricated for experimental validation. The results
demonstrate significant backscattering enhancement over
a broadband from 4.0 to 7.0 GHz (54.5%) for dual
polarizations. With respect to a bare metal target
without the metamaterial, the y-polarized backscattering
is enhanced to 97.5% over a metal plate of identical
projected area, and the x-polarized backscattering
reaches 74.5%.

Metasurface absorbers, as a type of two-dimensional
metamaterial, control electromagnetic waves by adjusting
the phase, amplitude, and polarization response of the
units. Traditional design methods face challenges with
high computational costs and low optimization
efficiency. This paper proposes a semantic-guided,
cross-modal end-to-end intelligent design framework,
combining natural language processing and deep learning.
A SigLIP-based visual-language alignment module connects
natural language descriptions with target spectra, while
a forward modeling method based on the SV-MC-FNO
addresses the multi-solution problem in inverse design
using a mixture density network (MDN). The introduction
of cyclical consistency training with physical
constraints enhances model reliability. Experimental
results show significant improvements in design
efficiency and accuracy.

Frequency selective surface (FSS) absorbers are
inherently periodic electromagnetic structures whose
scattering characteristics are governed by the
superposition of Floquet modes. When the structural
period satisfies specific conditions, higher-order
Floquet modes (i.e., grating lobes) become propagation
and carrying additional scattering power. This energy is
not captured by conventional fundamental-mode
S-parameters, which may lead to inaccuracies in
conventional absorptivity evaluation based on |S11| and
|S21|. In this work, the modal composition of the
scattered fields of an FSS absorber is analyzed using
Floquet theory. A broadband resistive-sheet FSS absorber
is employed as an example to compare reflection
characteristics and absorptivity with
fundamental-mode-only and full-mode considerations. The
results demonstrate that, when higher-order propagating
modes are included, the 90% absorption bandwidth shrinks
from 6.6 – 27.4 GHz to 6.6 – 20 GHz.

This paper presents a novel 3-D FSS sensor for the
high-accuracy dielectric characterization of liquid
materials across a wide dynamic range. Featuring a
miniaturized honeycomb lattice and an ultrathin profile,
the proposed architecture uniquely leverages surface
tension for stable liquid retention. To interpret the
spectral response, a systematic two-step analytical
framework is developed, mapping specific higher-order
harmonic resonance peaks to low, medium, and high
dielectric constants. Furthermore, the sensor’s high
frequency selectivity and multiple harmonic resonances
are intuitively elucidated via Smith chart impedance
trajectories, providing profound physical insight into
the underlying matching mechanisms.

This review synthesises recent advances that
co-optimise materials and electromagnetics for robust
wearable antennas. It adopts a materials-aware design
mindset that treats the substrate, radiator, and ground
as coupled variables. In practice, one can shape
dielectric loss and effective permittivity only where
they matter; form the operating spectrum through
interpretable modal control rather than add-on
resonators; manage non-ideal conductors via coordinated
radiator-ground co-design; miniaturise through
ground-mediated propagation control; and embed
biosymbiotic mechanics using additive manufacturing.
Together, these strategies provide practical,
material-oriented, application-focused guidance for
future WBAN platforms.

This work addresses the electromagnetic field (EMF)
safety of a capsule robot moving inside the human body
during wireless power transfer (WPT) operations. The WPT
system consists of an innovative birdcage coil capable
of generating a nearly uniform rotating magnetic field
with non-zero components along all three spatial axes.
This solution is wearable, enabling comfortable and
efficient power transfer to any patient. However, for
obese human body models (HBMs), the current needed to
transfer a reasonable power to the capsule battery could
pose several EMF exposure risks due to the deeper colon
tract and larger body cross-sections. A dosimetric
analysis is therefore performed to assess compliance of
the proposed WPT system with EMF safety standards.
Different frequencies and HBMs are investigated to find
the worst-case scenarios.

A novel wideband terahertz interconnection between
microstrip line and waveguide is proposed for full-band
applications, addressing the requirements of
high-frequency test equipment, radar modules, and
communication systems. A short-circuited stub is newly
introduced to enhance the performance of the
microstrip-to-waveguide transition. The short-circuited
stub adjacent to the probe provides additional inductive
loading, generating multiple resonant matching
frequencies and thereby improving impedance matching
across a wider bandwidth. With the proposed
interconnection scheme, the D band is entirely covered,
and in the frequency range from 95 GHz to 200 GHz, the
simulated return loss and insertion loss are better than
-15 dB and -0.75 dB. To experimentally validate the
design, a back-to-back probe transition is fabricated.
The measured return loss and insertion loss are better
than -13 dB and -1.1 dB, respectively, from 103 GHz to
177 GHz, demonstrating excellent wideband performance.
The proposed interconnection exhibits not only broad
operational bandwidth but also strong potential for
compact integration in high-frequency systems.

Over the past two decades, metamaterials and
metasurfaces have revolutionized the field of
electromagnetics by enabling unprecedented control over
electromagnetic waves through engineered subwavelength
structures. This invited talk presents a comprehensive
overview of the research contributions in our group from
2006 to 2026, highlighting innovative developments in
metamaterial and metasurface-inspired technologies for a
wide spectrum of wireless and sensing applications.

The talk will cover the evolution of compact and
multifunctional antennas, high-selectivity microwave
filters, and advanced metasurface-enabled systems
addressing the growing demands of modern wireless
communications. Special emphasis will be given to the
development of antennas for 4G/5G and beyond systems,
cognitive radio platforms with frequency-reconfigurable
and spectrum-sensing capabilities, and compact wideband
radiators employing artificial electromagnetic
structures for enhanced performance. Furthermore, the
presentation will discuss recent advances in RF energy
harvesting and rectenna technologies, including
metasurface-assisted wireless power transfer and ambient
energy-scavenging systems aimed at sustainable and
self-powered wireless networks.

The talk will also highlight the translation of
theoretical concepts into experimentally validated
prototypes and practical systems, demonstrating how
metamaterials and metasurfaces have evolved from
scientific curiosities into enabling technologies for
next-generation communication, sensing, and energy
applications. Finally, future research directions
involving intelligent metasurfaces, integrated wireless
power and communication systems, and sub-THz platforms
for 6G applications will be outlined.

This paper presents a 67-110 GHz low-noise amplifier
(LNA) module designed to suppress harmful resonances
within a metallic packaging cavity, which can otherwise
lead to self-oscillation and performance degradation. By
optimizing the cavity dimensions and incorporating
specifically designed perturbation structures, the
proposed approach effectively eliminates unwanted
resonant modes. The viability of the design is
experimentally verified, with measurement results
confirming stable LNA operation across the full
frequency band.

Additive Manufacturing (AM) offers exciting
capabilities for microwave engineering, enabling rapid
prototyping, geometric flexibility, and easily
customizable products. However, applying 3D printing to
high-performance filters is not immediate, as these
technologies are not originally tailored for
high-frequency hardware. To meet strict electrical
specifications, specific design adaptations and targeted
post-processing steps are often required. This
presentation highlights how AM can be effectively
leveraged to build advanced microwave filters. Using
selected hardware examples, we will discuss some of the
most common 3D printing techniques adopted in this field
and the practical actions needed to ensure optimal
component performance. Finally, the talk will
demonstrate how the geometric freedom of AM unlocks
unconventional 3D topologies, allowing the development
of a new class of filters that are highly optimized in
terms of compactness, weight, and insertion losses.

The race to develop next-generation wireless
electronics is accelerating at a rapid pace. Thanks to
advanced additive manufacturing technology, fast
prototyping, low-entry-cost, and in-house short-run
manufacturing empower millions of start-ups and
companies with demanding confidentiality and accelerated
innovation. We aim to build a new class of
high-performance metamaterials and metasurfaces to
advance the knowledge for future wireless devices.
Compact and low-cost 3D-printed metasurfaces and
metamaterials will be delivered to circumvent the
limitations of traditional manufacturing technologies.
The proposed 3D metadevices should be easily integrated
into high-speed wireless systems in a dynamic
environment. The cutting-edge additive manufacturing
technologies advance 3D Radio frequency circuits with
exceptional performance for emerging intelligent and
immersive technologies, which will critically impact
5G/6G high-speed wireless devices in the millimetre-wave
and terahertz applications. The 3D-printed radio
frequency electronics will immediately benefit
biomedical engineering, defence, space and
telecommunication industries.

The increasing complexity of high-frequency
transmission and reception front-ends resulting from the
addition of new frequency bands and frequency
diversification, requires reconfigurable topologies
throughout the entire telecommunication chain (antennas,
phase shifters, filters, amplifiers, etc.) for reducing
fabrication costs, system size, and overall power
consumption. Most reported reconfiguration solutions in
RF circuits are based on the integration of localized
tunable devices and commonly rely on semiconductor-based
devices, RF-MEMS, liquid crystals or functional
materials. We are presenting the performances of a
selection of reconfigurable devices (switches, tunable
capacitors, agile filters, frequency- and polarization-
reconfigurable antennas) designed for millimeter-waves
operation and built upon a variety of constituent
functional materials with controlled and tuned
permittivity or conductivity (ferroelectrics, phase
transition and phase change materials). We discuss the
requirements for materials integration and emphasize the
advantages of specific reconfiguration schemes enabling
devices with on-demand agile functionalities.

Imaging biological cells at sub-terahertz (sub-THz)
frequencies is difficult because cellular structures
often exhibit
weak scattering and low dielectric contrast. We report a
100-GHz scattering-type scanning near-field optical
microscopy (s-SNOM) platform designed to improve
sensitivity for label-free cellular measurements. The
system combines a zero-intermediate frequency (Zero-IF)
detection architecture with strong transmitter-receiver
isolation and a custom probe with an approximately
100-nm tip radius. As a proof of concept, we image
semi-dry SKOV3 ovarian cancer cells on a Au-coated
substrate and distinguish two morphological states: a
rounded, poorly differentiated state and an elongated
state. Measurable near-field contrast is retrieved via
first- and second-harmonic demodulation, yielding stable
1st-2nd order near-field signals at 100 GHz.

Terahertz scanning type near-field optical microscopy,
as high-resolution imaging platforms with
nanometer-scale resolution, have been extensively
utilized in materials science, physics, and biological
research. Central to this imaging mechanism is the use
of nanoscale probe tip vibration to modulate incident
electromagnetic waves. By selectively detecting the
scattered signals arising from tip-sample interactions
and extracting near-field information from both the
fundamental vibration frequency components (termed
first-order signals) and their harmonic frequency
components (e.g., second-order signals or higher-order
signals), these systems achieve nanometric spatial
resolution.

To address the issue of unstable power supply caused by
the difficulty in maintaining continuous beam alignment
between transmitting and receiving antennas due to the
dynamic changes in drone flight attitude, this study
proposes a design for a beam-steering rectenna array.
First, a pattern-reconfigurable receiving antenna
element was designed by integrating a PIN diode
switching network into the antenna parasitic layer.
Second, a rectifier circuit suitable for wide input
power ranges was designed using a dual-parallel Schottky
diode topology. Finally, the designed antenna element
and rectifier circuit were integrated into a rectenna
element using a bent structure and a shared ground plane
via the antenna’s metal ground. The impact of the DC
bias circuit structure on antenna performance was
analyzed, and a 2×2 beam-steering rectenna array was
constructed. Test results of the rectenna array at
different power transmission distances show that the
array can electrically adjust the receiving antenna beam
direction. When the array is rotated to the
aforementioned three angles, the maximum DC power
received is 1.6 W, 1.2 W, and 1.3 W, respectively.

Near-field meta-steering (NFMS) antennas have emerged
as an effective class of beam-steering antennas for
applications such as high-power microwave systems and
are increasingly extending into the terahertz domain
since their first
introduction in 2017. These antennas have gained
significant interest in both academia and industry due
to their low profile, ease
of implementation, and excellent performance. This
manuscript presents several emerging implementations of
NFMS antennas in
high-power microwave and THz applications. As an example
case study, a simple one-dimensional beam-steering
antenna system is demonstrated to illustrate the
operating principle. The proposed antenna employs a
short horn feed, whose gain is enhanced by
11 dB while the beam is tilted to 19° using a
dual-purpose near-field phase transformation
metasurface. The proposed design is
capable of steering the beam in the azimuth plane from
0° to 360°.

This article presents a single-substrate
Pancharatnam-Berry (PB) phase metasurface capable of
dynamically steering vortex beams carrying orbital
angular momentum (OAM). Based on the Huygens’ resonance
principle, the proposed metasurface achieves an overall
thickness of only 0.125λ₀ and a maximum transmission
coefficient of −0.29 dB at 37.4 GHz. By spatially
translating a left-hand circularly polarized (LHCP)
patch antenna, high-purity OAM beams with a scanning
range of ±10° are realized. The proposed design provides
a compact and efficient solution for generating
steerable vortex waves, showing significant potential
for high-capacity wireless communication and sensing
applications.

This paper reports a low-loss on-chip optically tunable
terahertz (THz) ring modulator (TRM) based on an
all-silicon platform. Optical pumping technology enables
the device to achieve active tunable resonant response
with a minimum through-insertion loss of just 2 dB,
dynamically controlling the coupling state from the
overcoupled region to the critical region and then to
the undercoupled region. At 458.75 GHz, modulation depth
reaches 22.7 dB with an optical control speed exceeding
150 kHz, demonstrating practical value for high-speed
switching and modulation. These findings represent a
significant step forward in THz photonics by introducing
a tunable ring resonator that combines electromagnetic
field manipulation, reconfigurable coupling states, and
on-chip compatibility, opening opportunities for
applications in nonlinear optics, microcavity optics,
and photonic integrated circuits (PICs).

This paper presents a fully integrated 110-150 GHz
on-off keying (OOK) receiver implemented in 65-nm CMOS
technology. To enable high-speed transmission despite
parasitic limitations in the D-band, the proposed design
features a wideband low-noise amplifier (LNA) with
parasitic-aware layout optimization, a gain-boosted
envelope detector (ED), and a bandwidth-extended
baseband amplifier. The LNA achieves a peak gain of 20.3
dB with a 3-dB bandwidth of 40 GHz. The complete
receiver occupies an area of 0.49 mm² and consumes 62.6
mW from a 1.2 V supply. At a carrier frequency of 130
GHz, the receiver supports data rates exceeding 25 Gb/s
with an energy efficiency of 2.5 pJ/bit.

This work proposes a multistage transimpedance
amplifier (TIA) with multiple bandwidth and gain
extension techniques. The
TIA exhibits a high transimpedance gain of 105 dBΩ, a
sensitivity
of −8.2 dBm, and a data rate of 20 Gbps for
non-return-to-zero
(NRZ) scheme. The demonstrated results validate the
proposed TIA
for high-speed and low-noise intelligent optical
communication systems.
Bandwidth extension is achieved through techniques such
as parasitic shunt capacitance splitting and inductive
peaking are applied across
various stages. To maximize gain, the TIA incorporates a
single-input-to-differential circuit implemented using a
simple RL shunt feedback
inverter. Additionally, a differential amplifier
followed by a buffer
circuit contributes an additional gain of 16 dB. The
design achieves an
input-referred noise current density of 2.5 pA/√Hz and
consumes a
total power of 1.5 mW. The proposed TIA is implemented
in a 65-nm
TSMC technology node, operating at a nominal supply
voltage of 1.2
V. The complete chip, including I/O pads, occupies a
compact area of
1 mm2.

To meet the growing ultra-low power demand in
backscatter sensing networks, switching modulation
(e.g., OOK/BPSK) is widely adopted. Yet existing
backscatter modulators confront the challenges of
inherent static power consumption with SPDT switches and
signal crosstalk. To address these issues, this paper
proposes an ultra-low power modulator employing
near-zero static power failsafe SPST switches for
backscatter communication supporting OOK and BPSK with
the quiescent power lower than 1 µW.

This paper presents a millimeter-wave (mm-wave) Doherty
power amplifier (PA) monolithic microwave integrated
circuit (MMIC) fabricated in a 0.1-µm gallium arsenide
(GaAs) process for 5G-NR FR2 applications. To extend
bandwidth, a series voltage combining architecture is
adopted for output power synthesis. A compact
three-coupled-line balun is implemented to realize
low-loss differential-to-single-ended combining. In
addition, an adaptive bias technique is applied to the
peak amplifier output stage to improve AM-AM linearity.
The proposed PA operates at 24-30 GHz. Simulation
results show a small-signal gain of 13.5 dB and a
large-signal gain of 14 dB. The saturated output power
is 27.6-28.3 dBm. A peak power-added efficiency (PAE)
above 35% is achieved, with PAE exceeding 30% at 6-dB
back-off and 25% at 8-dB back-off. The AM-AM distortion
is within ±1.2 and the AM-PM variation is less than 18°.
The chip area is 2.2 mm × 1.6 mm.

A pillbox beamforming network (BFN) based W-band
multibeam antenna is proposed in the paper. The antenna
is composed of a BFN, several phase delay lines, and a
ridged waveguide (RWG) slot array. The phase delay lines
convert the rectangular waveguide output ports of the
pillbox BFN to the RWG, thus reducing the element space
between the adjacent radiation slots and increasing the
beam scanning range. Additional phase compensation is
used to optimize the SLL and gain of beams, which is
realized by the taper width of the RWG. The simulated
results show that the antenna can achieve the beam
scanning range of ±45°, and the gain variation of the
beam switching is below 2.3 dB.

Currently reflective intelligent surface (RIS)
implementations typically rely on semiconductor switches
(e.g., PIN diodes or transistors) hence require
continuous biasing, leading to non-negligible static
power consumption that scales with the number of unit
cells. Here we present an highly energy-efficient,
efficient, intelligent surface enabled by non-volatile
2D-material-enabled RF switches. The switch is
consisting of sandwiched Ag/MoS₂/Ag structure and
exhibits stable non-volatile resistive switching and
favorable RF characteristics, enabling two persistent
states without DC holding power. By integrating these
switches into a 1-bit reflective unit cell, a 6×6 RIS
prototype operating at 3.5 GHz is demonstrated with
programmable reflection patterns under different coding
sequences, validating its capability for beam steering
and wavefront control. Furthermore. system-level energy
benefit of eliminating static bias power, which becomes
increasingly significant for large-scale RIS and sensing
arrays is presented. These results indicate that
non-volatile 2D-material switches provide a practical
pathway toward low-power pro-grammable metasurfaces for
6G wireless communications.

In this paper, a metasurface based on a compact curved
broadside-coupled stripline (BCS) phase shifter is
proposed for gain enhancement applications. The unit
cell consists of a receiving antenna, a BCS phase
shifter, and a transmitting antenna, all fabricated
using standard printed circuit board (PCB) technology.
The proposed metasurface exhibits stable radiation
performance with a boresight gain of approximately 19
dBi and cross-polarization levels below -20 dB, and a
3-dB gain bandwidth of 18% (25 – 30 GHz).

This study presents a thermally actuated, dynamically
reconfigurable FSS utilizing laser-cut Ni-Ti SMA
elements. By exploiting a bistable SMA architecture, the
unit-cell topology is physically reconfigured via
temperature-triggered deformation, thereby re-routing
the surface current paths without the need for complex
voltage-biasing networks or bulky mechanical assemblies.
The proposed FSS seamlessly transitions between two
distinct spectral states: a highly selective
high-frequency narrowband response when the SMA branches
are engaged and a broadband response in the
lower-frequency regime when the branches are disengaged.
Correspondingly, the fractional bandwidth dynamically
expands from 5.66% to 51.72%. The underlying
electromagnetic mechanisms and bandwidth transition are
further elucidated through Babinet’s principle and
Smith-chart impedance trajectories.

A continuously tunable phase shifter based on liquid
crystal from 10 GHz to 60 GHz is presented. In this
design, most of the waves travel through the LC mixture
via a post-wall coplanar waveguide, rather than the
traditionally employed inverted microstrip line,
maximizing the liquid crystal’s tunability.
Additionally, the proposed design offers straightforward
fabrication and improved mechanical stability compared
to the stripline designs. To validate the effectiveness
of the proposed design, three delay line phase shifters
employing inverted microstrip line, stripline, and
post-wall coplanar waveguide are designed and simulated.
The results show that, while all the structures have
reflection coefficients less than -18 dB, the suggested
structure demonstrates figure of merit values between
89.6 Degree/dB and 124.9 Degree/dB, which is, on
average, 35 % greater than those attained by stripline
designs. The enhanced FoM and decreased fabrication
complexity make the proposed structure a promising
candidate for applications in millimeter-wave
beamforming.

The terahertz (THz) frequency band (0.1-10 THz) offers
immense potential for advanced imaging applications due
to its non-ionizing nature, ability to penetrate
non-polar materials, and distinctive spectral
signatures. A critical component of THz systems is the
THz lens, which facilitates high-resolution biosensing,
biological imaging, and the detection of concealed
details. However, traditional dielectric refractive
lenses are bulky, suffer from significant aberrations,
and often fail to achieve the high imaging resolution
required for emerging applications. To overcome these
limitations, metasurfaces have been widely employed in
the design of THz metalenses. Metasurfaces provide a
compact and versatile alternative to traditional lenses.
In this talk, we will present various THz metalens
designs, including achromatic metalenses,
hyper-dispersive metalenses, and super-oscillatory
metalenses, all fabricated using advanced dielectric 3D
printing technology. We will also highlight their
transformative applications, such as THz
super-resolution imaging, axial-scan-free 3D object
imaging, and resilient wireless communications. These
3D-printed metalenses, with their unique
characteristics, pave the way for next-generation
compact, high-resolution, and in vivo THz imaging
systems.

The terahertz (THz) frequency band (0.1-10 THz) offers
immense potential for advanced imaging applications due
to its non-ionizing nature, ability to penetrate
non-polar materials, and distinctive spectral
signatures. A critical component of THz systems is the
THz lens, which facilitates high-resolution biosensing,
biological imaging, and the detection of concealed
details. However, traditional dielectric refractive
lenses are bulky, suffer from significant aberrations,
and often fail to achieve the high imaging resolution
required for emerging applications. To overcome these
limitations, metasurfaces have been widely employed in
the design of THz metalenses. Metasurfaces provide a
compact and versatile alternative to traditional lenses.
In this talk, we will present various THz metalens
designs, including achromatic metalenses,
hyper-dispersive metalenses, and super-oscillatory
metalenses, all fabricated using advanced dielectric 3D
printing technology. We will also highlight their
transformative applications, such as THz
super-resolution imaging, axial-scan-free 3D object
imaging, and resilient wireless communications. These
3D-printed metalenses, with their unique
characteristics, pave the way for next-generation
compact, high-resolution, and in vivo THz imaging
systems.

Owing to their short wavelength and light-like
propagation behavior, terahertz waves require
quasi-optical components to control the flow of
radiation. To meet this need, 3D-printing has evolved
over the past decade from a niche technique to a highly
customizable, general-purpose methodology to produce
terahertz quasi-optics, using consumer-grade hardware.

The field of microwave photonics has evolved
significantly over the last decade, ushered by the
breakthroughs in integrated photonics in realizing
integrated microwave photonic devices with an array of
functionalities packed on a nanoscale footprint. The
combination of photonic integration with microwave
photonics, enables the realization of reproducible,
compact, lightweight, low-power consumption and low-cost
microwave photonic systems that are physically and
economically competitive against their electronic
counterparts. Microwave photonics techniques have
attracted dramatically increased attention. In this
paper, we present recent advances across three
interconnected themes: adaptive RF signal processing,
high performance sensing, and photonic neural computing.

We first discuss adaptive microwave photonic
interference mitigation for dynamic RF environments. By
combining photonic amplitude and phase control, the
system can suppress unknown and time-varying
interference. Experimental results demonstrate robust
recovery of signals of interest under continuous-wave,
phase-modulated and multi-interference conditions. We
then present machine-learning-enhanced microwave
photonic sensing, where integrated photonic sensors
convert optical responses into rich RF spectral
signatures that can be interpreted by machine/deep
learning (ML/DL) models. In our recent work,
ML/DL-assisted microwave photonic sensors have enabled
athermal operation, noise resilience, multi-parameter
detection and extended sensing range. Finally, we
discuss our recent photonic neural network accelerators
based on inverse-designed nanophotonic structures. The
photonic neural network perform classification within
ultra-compact silicon photonic devices. The demonstrated
photonic neural networks achieve a computational density
of approximately 400 million parameters per mm²,
providing a scalable pathway towards energy-efficient
analog photonic computing.

In the information society, consumer electronic devices
naturally possess wearable and portable characteristics.
In light of this, we introduce a vital-sign detecting
system for consumer electronic devices that utilizes
wireless communication signals. Given the proximity of
these devices to the human body, radio frequency energy
is directed into a confined internal region, thereby
facilitating the modulation of backscattered signals
with pronounced bodily vibrations. Consequently, the
received signals exhibit variations corresponding to the
vital signs. After simply filtering out the high-speed
modulated digital information, target signals can be
obtained without complicated demodulation. The
theoretical framework, numerical computations, and
experimental results demonstrate congruence, thereby
validating the efficacy of the proposed methodology for
achieving stable, long-term monitoring across diverse
wearing scenarios. The average heart rate aligned with
the established gold standard, and the root-mean-square
error (RMSE) for instantaneous heart rate was 1.02 bpm.

Textile-integrated antennas have been the subject of
much investigation due in part to their easy integration
into everyday life. There are several methods that have
been established for creating textile-integrated
antennas. Two such methods are embroidery and knitting.
Both employ the use of existing textile manufacturing
methods and conductive threads and yarns. Embroidered
antennas have been studied extensively
and have made use of high precision, computer controlled
embroidery machines (A. Kiourti, C. Lee, and
J. L. Volakis, “Fabrication of Textile Antennas and
Circuits With 0.1 mm Precision,” IEEE Antennas and
Wireless Propagation Letters, vol. 15, pp. 151-153,
2016). Knitted antennas, on the other hand, have not
been as extensively studied. Some work has been done in
characterizing the effective sheet impedance of
knitted antennas and transmission lines, however this
was only done for a single knit pattern (M. A. S. Tajin,
C. E. Amanatides, G. Dion and K. R. Dandekar, “Passive
UHF RFID-Based Knitted Wearable Compression
Sensor,” in IEEE Internet of Things Journal, vol. 8, no.
17, pp. 13763-13773, 1 Sept.1, 2021). A major advantage
of knitted textiles is the ability to design and program
different mechanical properties of the textile
based on the knit pattern (Singal, K., Dimitriyev, M.S.,
Gonzalez, S.E. et al. “Programming mechanics in
knitted materials, stitch by stitch”. Nature
Communications 15, 2622, 2024).
This work will examine and characterize a variety of
textiles with differing knit patterns and will attempt
to establish a relationship between their mechanical and
electrical properties. This will be done using
techniques from metasurface design, where a knit stitch
will be treated as the unit cell and the bulk surface
impedance properties will be extracted from HFSS
simulations (A. M. Patel and A. Grbic, “A Printed
Leaky-Wave Antenna Based on a Sinusoidally-Modulated
Reactance Surface,” in IEEE Transactions on
Antennas and Propagation, vol. 59, no. 6, pp. 2087-2096,
June 2011). Those metasurface simulations will
then be used to design a pattern on a textile, which
will be manufactured and compared against the simulated
results.
This research was supported by an appointment to the
Intelligence Community Postdoctoral Research Fellowship
Program at The University of Illinois Urbana-Champaign
administered by Oak Ridge Institute for
Science and Education (ORISE) through an interagency
agreement between the U.S. Department of Energy
and the Office of the Director of National Intelligence
(ODNI)

Solar radio emissions provide critical insights into
dynamic solar atmospheric processes, including coronal
heating, solar eruptions, and solar wind acceleration.
We present a high-sensitivity, multi-channel receiver
system operating across the 15-36 GHz range,
specifically engineered to bridge observational gaps in
capturing non-thermal phenomena, such as small-scale
microwave bursts in the solar transition region. The
system architecture employs low-noise amplifiers (LNAs)
in the initial stage to minimize the overall noise
figure, followed by multi-band filters and power
dividers that split the signal into three primary
sub-bands-15-22 GHz, 22-29 GHz, and 29-36 GHz-supporting
dual-polarization observations. By integrating frequency
down-conversion with high-speed digital spectroscopy,
the system achieves the temporal and spectral resolution
requisite for characterizing rapid frequency drift and
transient burst dynamics in real-time. Currently, the
system is deployed at the Lenghu Station on the
Qinghai-Tibet Plateau at an altitude of 4,100 meters for
pilot observations. Comparative measurements of solar
and the cold sky demonstrate that the system possesses
high observational sensitivity. This successful
deployment validates the system’s efficacy for
comprehensive solar monitoring and establishes a robust
foundation for future observations aimed at advancing
solar physics and space weather research.

In this paper, the properties, preparation and
applications of PDMS-MWCNT composite is discussed. The
main focus of the paper remains on the applications of
flexible antennas used in wearable electronic devices.
The flow diagram of making of the PDMS and PDMS-MWCNT
composite is given. Moreover, the detailed analysis of
both materials in terms of scanning electron microscope
(SEM) is analyzed. Later, some examples are given from
the literature, which shows the role of these materials
in the antenna designing applications.

This paper presents a power-based direction-finding
(DF) scheme based on a space-time leaky-wave antenna
(STLWA) with fixed-frequency radiation null scanning
capability. The direction of arrival (DoA) can be
estimated by identifying the power-minimum angle between
two lobes in the spatial power spectrum. To be specific,
by programming the 1-bit phase-control unit cells with
distinct time-periodic signals, the amplitude of the
aperture field at the fundamental frequency can be
flexibly controlled. By leveraging space-time
modulation, the STLWA provides steerable radiation nulls
at the fundamental frequency. DF experiments are
conducted to validate the system’s performance. The
proposed approach offers a compact, phase-shifter-free,
fixed-frequency solution for sensing and localization.

This work presents a dual port, dual polarized
shared-aperture (monostatic) based planar antenna with
wideband interport isolation characteristics for sub-6
GHz simultaneous transmit and receive (STAR) or in band
full duplex (IBFD) wireless applications. The presented
compact metasurfaces antenna offers wider impedance
bandwidth and excellent interport isolation levels
across its entire operating bandwidth. The wideband
impedance bandwidth characteristics have been achieved
through combination of parasitic feeding and
electromagnetic band gap (EBG) radiator excited through
proximity feeding from modified four-pointed star shaped
driven patch. The high interport isolation levels across
entire operational bandwidth of the antenna have been
established through balanced transmit and receive modes
operation. The presented EBG antenna with unidirectional
radiation characteristics resonates at center operating
frequency of 3.75 GHz with -10 dB impedance bandwidth of
1.5 GHz (40%) spanning over 3 GHz to 4.5 GHz. The
isolation between transmit and receive ports of
presented antenna is better than 62 dB across the entire
operating bandwidth of 1.5 GHz. The presented dual port,
dual polarized antenna offers superior gain performance
for each port excitation attributed to the differential
excitation of EBG patch. The proposed unidirectional
antenna offers wider impedance bandwidth and high port
to port isolation levels across wider impedance
bandwidth compared to the earlier reported
unidirectional antennas intended for IBFD or STAR
applications.

This paper presents a low-profile beam-scanning
antenna, where the monopole antenna and metasurface are
integrated on the same plane for ultra-compact
configuration. A 7-mm-tall monopole antenna serves as
the feed to excite surface waves (SW), while the
metasurface generates Pancharatnam-Berry (PB) phase and
propagation (PG) phase to regulate SW radiation.
Specifically, the PB phase is fixed as a preset
component, and the PG phase features 1-bit
reconfigurable phase resolution. The broadband phase
responses of both phases endow the antenna with
excellent broadband radiation capability. At the
boresight direction (0 °), the antenna achieves a 16.6%
3-dB gain bandwidth spanning 10.5-12.4 GHz. Furthermore,
two-dimensional beam scanning over a range of ± 60 ° is
realized within the operating band, with a scanning loss
of less than 3 dB. Owing to its advantages of low
profile, high integration, and broadband radiation
performance, the proposed design is expected to be a
promising candidate for mobile communication
applications.

This paper presents a method for achieving scanning of
self-accelerating beams by simply reversing the phase
from 0 degree to 180 degree. Building upon conventional
approaches, this method leverages both gradient
amplitude and abrupt phase profiles, requiring only
phase manipulation to achieve beam scanning. A waveguide
slot antenna array is designed based on this principle,
and simulated results demonstrate its effectiveness and
feasibility

This paper presents a compact resonant cavity antenna
(RCA) enhanced by a single-layer negative-epsilon
surface (NEPS) metasurface operating at 300 GHz for
terahertz communication systems. The proposed
metasurface is composed of periodic circular patch
resonators engineered to exhibit a stable reflection
magnitude together with an effective negative
permittivity (ε<0) around the target frequency. These
electromagnetic characteristics enable efficient
manipulation of the reflection phase and control of the
electromagnetic wave propagation inside the Fabry-Perot
cavity. By regulating the reflection phase distribution,
the metasurface improves the near-field phase uniformity
and promotes constructive interference at the partially
reflective aperture, resulting in enhanced radiation
collimation and power radiation efficiency. Full-wave
numerical simulations demonstrate that the proposed
antenna achieves a maximum directivity of approximately
20 dBi with an aperture efficiency of about 40% while
maintaining a compact and low-profile structure. The
proposed NEPS-assisted RCA provides a promising
high-gain antenna platform for terahertz and future 6G
communication applications.

Terahertz wave possesses wide available high frequency
spectrum bandwidth and thus has potential applications
in high-resolution imaging sensing and high-speed
communication. Due to limitations in terahertz
integration technologies and MMIC manufacturing
processes, terahertz radar and communication systems
still face bottlenecks such as low power output, high
noise, and difficulties in array integration. The
front-end SiP integration is still one of the key
terahertz microsystem technologies. In the session, the
newly proposed integration solutions, such as the
planner transmission line and waveguide interconnection,
3D multilayer module, and multi-channel integration,
will be presented, and terahertz SiP arrays will be
further introduced for the high-speed communication.

Approaching the terahertz band from the electronics
side is of great technological importance, with the
promise of advancing next-generation wireless
communication systems toward 6G and beyond [1]. However,
inherent limitations of high-speed transistors, the
primary building blocks of monolithically integrated
high-frequency circuits, have hindered the realization
of high-performance terahertz electronics [2], [3].
Electrical metastructures offer an alternative paradigm,
in which electrical control of the conductivity of a
semiconducting layer manipulates collective
quasi-electrostatic responses within a device layout,
enabling electronic functionalities such as switching,
mixing, and parametric amplification. Compared with
conventional transistors, electrical metastructures
enable ultra-low contact resistances, leading to
record-high switching cutoff frequencies beyond 10 THz
in a compact device platform, referred to as electronic
metadevices [4]-[7].
The first part of this talk highlights recent advances
in III-nitride electronic metadevices operating up to 1
THz and introduces a new generation based on
quasi-one-dimensional electrical metastructures with
enhanced electrical performance [8]. We present
theoretical insights into the collective responses
governing the operation of electronic metadevices and
elucidate their ultimate performance limits. In the
second part, we introduce a metastructure-based paradigm
for directly realizing high-performance millimeter-wave
and terahertz components with ultracompact footprints,
demonstrated the compatibility of metatronic devices
with commercial silicon processes [9].

References
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“What should 6G be?” Nat. Electron., vol. 3, pp. 20-29,
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[2] K. Sengupta, T. Nagatsuma, and D. M. Mittleman,
“Terahertz integrated electronic and hybrid
electronic-photonic systems,” Nat. Electron., vol. 1,
pp. 622-635, 2018.
[3] W. Cao, H. Bu, M. Vinet, M. Cao, S. Takagi, S.
Hwang, T. Ghani, and K. Banerjee, “The future
transistors,” Nature, vol. 620, pp. 501-515, 2023.
[4] M. Samizadeh Nikoo and E. Matioli, “Electronic
metadevices for terahertz applications,” Nature, vol.
614, pp. 451-455, 2023.
[5] M. Samizadeh Nikoo and H. Wang, “Theoretical
foundation of electronic metadevices,” IEEE Electron
Device Lett., vol. 45, no. 3, pp. 456-459, Aug. 2023.
[6] M. Samizadeh Nikoo, C. Chu, B. Lin, Y. Liu, Y. Kim,
and H. Wang, “Active and integrated electronic
metadevices for future telecommunication circuits,”
Commun. Eng., vol. 4, Art. no. 49, 2025.
[7] A. Abushawish, Z. Huang, and M. Samizadeh Nikoo,
“Strong collective responses in quasi-1D metadevices for
millimeter-wave electronics,” IEEE J. of Microw., Early
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[8] A. Abushawish, Z. Huang, and M. Samizadeh Nikoo,
“Quasi-1D Electronic Metadevices With Enhanced
Electrical Properties,” IEEE Electron Device Lett., vol.
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[9] M. Samizadeh Nikoo, M. Eleraky, B. A. Abdelmagid, D.
Lee, F. Jazaeri, A. Wang, B. Lin, and H. Wang,
“High-power millimetre-wave switches on silicon using
displacement fields and tunnelling currents,” Nat.
Electron., vol. 9, pp. 84-92, 2026.

This paper presents a high-performance 510 GHz
monolithic GaAs Schottky barrier diode (SBD) frequency
tripler for terahertz local oscillator (LO)
applications. As the operating frequency extends into
the sub-millimeter-wave regime, traditional multipliers
are often limited by inaccurate parasitic modeling and
significant substrate-induced dielectric losses. To
address the parasitic modeling issue, a deterministic
two-port, four-structure parasitic extraction method is
proposed. Compared with conventional equivalent-circuit
modeling or empirical fitting methods, it enables
clearer separation of extrinsic parasitics and supports
more accurate parasitic modeling and Schottky diode
structure optimization.
Four specifically designed test structures-Single Pad
(SP), Pin-Open (PO), Diode-Short (DS), and Diode-Open
(DO)-are employed to systematically extract pad-related
parasitics (Lpad, Cpad), finger-related components (Lf,
Rf), and inter-electrode coupling effects (Cpp). By
de-embedding these extrinsic parasitics from
Y-parameters, a more accurate parasitic model of the SBD
can be established, which helps reduce the adverse
impact of overall parasitic effects on multiplier
performance and provides a basis for optimizing the
Schottky diode structure. The tripler is implemented
using a 3-μm-thick GaAs membrane process with backside
substrate etching, which removes the bulk GaAs to form a
thin-film structure and effectively reduces
substrate-induced dielectric loss and suppresses
parasitic substrate modes at 510 GHz. A balanced
topology is also adopted to suppress even-order
harmonics.
Experimental characterization was performed using a
frequency multiplier chain and an Erickson power meter.
The fabricated MMIC demonstrates robust performance
across the 490-530 GHz band. Under an input drive power
ranging from 63 to 104 mW, the tripler achieves a peak
output power of 3.72 mW at 508 GHz, with a maximum
conversion efficiency of 4.2%. Milliwatt-level output
power is maintained across the entire measured
bandwidth, although the upper end of the band approaches
the operating limit of the test equipment. These results
demonstrate that the proposed four-structure extraction
method and 3-μm thin-film technology together provide an
effective means of improving the output performance of
terahertz frequency triplers.

This paper presents the design and analysis of a
circular hollow polymer waveguide (CHPW) operating at
W-band (75-110 GHz). The proposed structure consists of
an air core surrounded by a polymer cladding, which
effectively reduces dielectric loss compared to solid
polymer waveguides. Mode analysis reveals that the
designed CHPW supports single-mode propagation
throughout the entire W-band, with the fundamental HE11
mode and higher-order TM01 mode identified. Parametric
studies show that increasing the inner radius or polymer
thickness raises both the phase and attenuation
constants, with polymer thickness exhibiting a more
significant influence. Material comparison indicates
that PTFE offers lower loss and wider single-mode
bandwidth than HDPE and PMMA, making it a promising
candidate for terahertz (THz) applications. Compared
with circular solid polymer waveguides (CSPW), the CHPW
demonstrates lower attenuation and broader single-mode
bandwidth but suffers from weaker field confinement.
This work provides a useful guidance for the development
of polymer waveguides at THz frequencies.

Terahertz field-effect transistors integrated with
metasurfaces (TFsurfaces) hold significant promise for
high-sensitivity chemical detection and imaging.
However, optimizing the asymmetric interdigitated
grating gate (AIGG) structure remains challenging due to
complex near-field coupling effects and a
high-dimensional parameter space spanning periodicity,
gate number, asymmetry coefficient, and structural
dimensions. Conventional empirical design methods are
inefficient and struggle to globally optimize these
detectors. This paper proposes a hybrid intelligent
modeling framework that combines a Feature Tokenizer
Transformer (FT-Transformer) with Extreme Gradient
Boosting (XGBoost) to accurately predict the
electromagnetic spectral response of TFsurfaces from
structural parameters. Structure-frequency joint inputs
are encoded by the FT-Transformer to capture complex
nonlinear feature interactions; the resulting deep
embeddings are then concatenated with original
structural parameters and fed into XGBoost for
regression. Evaluated on an independent test set, the
proposed model achieves an (R^{2}) of 0.9985 and an MSE
of (1.8 \times 10^{-5}), outperforming single-model
baselines. This data-driven framework significantly
accelerates the design of high-sensitivity THz detectors
and offers a scalable solution for complex metasurface
optimization.

High-temperature superconducting (HTS) technologies
have many potential applications, such as power
transmission, medical imaging, quantum computing,
military and aerospace, etc., due to their significant
advantages of high energy efficiency, easy cooling as
well as high reliability and stability. High-temperature
superconducting technologies also play a critical role
in wireless communications as they offer unique
advantages for applications in high-frequency
electromagnetic domains. High-sensitivity and broadband
nature of superconducting devices can be applied for
high-speed wireless communication systems, especially
the heterodyne mixers are highly desirable for high-gain
and low-noise RF receivers. This talk will introduce a
series of monolithic microwave integrated circuits
(MMICs), mainly heterodyne mixers and on-chip antennas,
which are used in microwave and millimeter-wave RF
receivers. The MMIC mixers are developed based on the
quantum tunnelling effect of Josephson junctions and
will significantly reduce power consumption and enhance
the sensitivity of RF receivers. Besides, advanced
antenna technologies, including the packaging techniques
of a high-gain waveguide antenna with MMICs and a
frequency-scanning leaky-wave antenna, will also be
touched in this talk.

Reconfigurable filters are key components in the
development of agile multi-standard receivers.. This
talk starts by addressing the needs for using multi-band
and tunable filters in wireless communication systems
and in flexible satellite payloads. It then addresses
existing tuning technologies, providing a comparison
between piezoelectric, Semiconductor, MEMS and PCM
tuning elements in terms of linearity, insertion loss,
suitability for use at millimeter-wave frequencies and
ease of integration with high-Q filters. It outlines
major design considerations for tunable filters
presenting techniques to realize tunable filters with an
absolute constant absolute bandwidth and a constant
frequency spacing between transmission zeros, over a
wide tuning range. The talk also illustrates examples of
tunable filters and diplexers tuned only a by single
tuning element, while exhibiting a constant absolute
bandwidth. It then addresses approaches for realizing
multi-band filters including dual-band and triple-band
filters. Finally, it presents techniques for realizing
multi-band filters where the various bands are tunable
in both center frequency and bandwidth. Very recent work
on realizing reconfigurable acoustic filters is also
presented.

Microwave and RF design engineers always seek to
develop a design that will meet specifications the first
time that the circuit is fabricated. To do so requires
that as many elements and phenomenon as possible
associated with the control devices and circuit be
accurately modeled. In the case of the microwave and RF
semiconductor control circuits, accurate modeling of the
solid-state control components over frequency, voltage,
current and power is key to successful control system
design. This talk will cover material that will provide
the RF and microwave design engineer insight into the
physical operation and modeling of semiconductor devices
for high-speed reconfigurability: PIN diodes and
field-effect transistors (FETs) as control components
and their use in microwave and RF control circuits. The
talk will briefly cover basic RF and microwave control
circuits for reconfigurable electronics, and then focus
on linear and nonlinear models for PIN diode, MESFET and
MOSFET control elements to implement these circuits. The
talk will conclude with control circuit examples using
these models for use in reconfigurable RF and microwave
electronics.

High-performance waveguide filters are critical
components in space communications, where mass reduction
and signal integrity are paramount. This presentation
explores the design and realization of these devices,
comparing traditional high-precision CNC milling with
emerging Additive Manufacturing techniques. By
evaluating experimental results, we analyze how
different fabrication perspectives influence design
flexibility, surface roughness, and overall RF
performance in demanding space environments.

Since its seminal publication in 2017, The Near Field
Meta-Steering (NFMS) technology, which is also known as
Near-Field Phase Transformation or Risley Prism Method,
has become popular worldwide to find solutions to
beam-steering challenges from microwaves through
millimeter-wave to Terahertz, in both academia and
industry. Especially it has significant advantages over
alternatives at millimeter-wave, sub-Terahertz and
Terahertz frequencies in which alternative methods for
steering narrow beams have significant challenges.
Another advantage is its very high radio-frequency
efficiency relative to alternatives when steering high
power microwave beams. This invited semi-plenary speech
will review the progress of this technology since its
invention, and outline what can be expected in the
future.

This talk presents the development of printable
nonlinear passive tags and portable harmonic radar
systems for clutter-resilient contactless monitoring and
tracking across object localization and biomedical
sensing applications. The research integrates compact
nonlinear tag design, scalable fabrication strategies,
and high-linearity harmonic radar architectures
operating at 4-8 GHz and 8-16 GHz. By exploiting
second-order harmonic generation from passive
diode-based tags, the system selectively detects
nonlinear responses while inherently rejecting linear
environmental reflections, enabling reliable operation
in electromagnetically complex and motion-rich
environments.

At the tag level, lightweight, battery-less nonlinear
transponders were designed using Schottky diodes
embedded within dipole-based and multi-element antenna
geometries optimized for harmonic radiation. Early
prototypes were fabricated using laser-cut masks and
conductive coatings, enabling rapid, low-cost
implementation of passive tags capable of meter-scale
detection without onboard power. Multi-element
configurations increased effective aperture and enhanced
harmonic signal strength, significantly improving
signal-to-noise ratio. Subsequent implementations
advanced toward inkjet-printed and materials-dispensed
structures on flexible substrates such as paper and PET,
producing compact millimeter-scale tags suitable for
conformal attachment to curved surfaces, including the
human chest. Full-wave electromagnetic simulations were
employed to optimize impedance matching, radiation
characteristics, and antenna-diode integration at both
fundamental and harmonic frequencies, ensuring efficient
nonlinear conversion and stable backscatter performance.

At the system level, two harmonic radar platforms were
developed. The 4-8 GHz harmonic radar system transmits a
4 GHz fundamental tone and receives the 8 GHz second
harmonic generated by the nonlinear tag. The
architecture incorporates frequency multiplication,
cascaded filtering, and carefully distributed
amplification stages to maintain transmit-receive
isolation and suppress harmonic leakage. The 8-16 GHz
harmonic radar system follows the same nonlinear
detection principle, transmitting at 8 GHz and receiving
at 16 GHz. Implemented on a multilayer PCB platform,
this configuration employs high-linearity gain stages,
low-pass and high-pass filtering networks, and coherent
down-conversion to baseband for signal processing. Both
systems operate in continuous-wave mode and emphasize
spectral purity and harmonic isolation to ensure robust
detection of weak nonlinear returns.

For biomedical applications, battery-free wearable tags
attached beneath clothing enabled accurate, noninvasive
respiratory monitoring with strong agreement with
ground-truth measurements, even in the presence of
nearby moving subjects and high radar cross-section
reflectors. Beyond healthcare, the same nonlinear
tagging principle supports lightweight object
localization and tracking without onboard power.

Collectively, this presentation establishes a scalable
framework that combines printable nonlinear tags with
compact harmonic radar devices, enabling selective
clutter-resilient detection for healthcare monitoring,
asset tracking, search applications, and emerging
nonlinear IoT sensing systems.

Magnetostatic surface waves (MSSWs) have been widely
utilized in microwave ferrite devices due to their
nonreciprocal propagation and ease of excitation.
Conventional MSSW-based devices typically employ a
single propagation channel. However, as microwave
ferrite devices move toward higher integration density
and multi-channel operation, unwanted reflections within
a single MSSW channel and coupling between adjacent
channels can lead to signal interference and performance
degradation. Therefore, effective suppression of MSSW
reflections and isolation between channels become
crucial. In this paper, MSSW termination using metallic
patterns is proposed to achieve both reflection
suppression and inter-channel isolation. The termination
mechanism is analyzed based on the dispersion relation
of MSSWs. Bowtie- and zigzag-shaped metallic patterns
are introduced to redirect waves and achieve MSSW
termination. A test device incorporating two MSSW
channels is designed and fabricated for validation.
Measurement results confirm that the proposed structures
effectively suppress reflections within a channel and
reduce coupling between adjacent MSSW channels.

This paper presents an ultra-wideband (UWB)
millimeter-wave energy selective surface (ESS) designed
for adaptive electromagnetic protection in complex
environments. The core innovation lies in the
utilization of a symmetrical bow-tie topology that
achieves an exceptionally broad transmission window. By
loading adaptive GaAs PIN diodes at the center of the
resonators, the surface dynamically reconfigures its
impedance based on the incident power level. Simulation
results demonstrate that the ESS provides a
low-insertion-loss (IL < 1 dB) transparent window
from 4 GHz to 16.7 GHz. Under high-power microwave (HPM)
incidence, the surface provides robust shielding
effectiveness (SE) exceeding 10 dB from 4 GHz to 12 GHz.
The proposed ESS effectively balances the requirements
of wideband communication and high-intensity
interference mitigation.

This paper presents a reflection-type true time-delay
(TTD) phase shifter based on propagation-controlled
reflective loading, combining the compactness of
conventional reflection-type phase shifters with
frequency-linear phase response. By switching the
electrical length of short-circuited reflective
transmission lines, the proposed architecture achieves a
constant group delay, satisfying the fundamental TTD
condition. Simulated results across 3GHz-8 GHz
demonstrate maximum phase range exceeding 360 deg, group
delay variation within 20 ps, insertion loss below 0.3
dB, and return loss exceeding 10 dB.

This work proposes a wideband dual-polarized bandpass
frequency selective surface (FSS) with ultra-large-angle
stability for application scenarios under large-angle
incidence. To overcome the inherent TE-TM wave impedance
mismatch at large incident angles, a
polarization-decoupling design methodology is employed.
Based on this strategy, individual TE- and TM-polarized
FSSs are developed, featuring stable wideband
performance across 0-75° incidence and low
cross-polarization interference. The desired
dual-polarized FSS is then obtained by orthogonally
combining the two types of FSSs, and further dimensional
adjustment ensures an excellent polarization consistency
in both transmission magnitude and phase. Simulation
results show that across 45-75° incidence, the proposed
FSS achieves a dual-polarization −3-dB passband of 7-13
GHz (60%), with a transmission phase difference of less
than 25° between TE and TM polarizations. These
simulations effectively validate the feasibility and
superiority of the proposed design strategy.

In this paper, spatial coupling is introduced in the
design of a three-dimensional (3-D) bandpass frequency
selective surface (FSS). The 3-D configuration naturally
establishes additional spatial coupling paths among the
ports and resonators. As a result, both the source and
load are coupled to each resonator as well as to each
other, allowing an N-th-order FSS to generate N
transmission zeros (TZs). This behavior enhances the TZ
generation capability compared with conventional filter
synthesis theory. To demonstrate this concept, a
third-order 3-D FSS is designed, which exhibits three
TZs. The resonant elements are realized using microstrip
resonators, leading to a compact implementation with
structural simplicity. The simulated results confirm the
feasibility of incorporating spatial coupling into the
design of 3-D bandpass FSSs

This invited talk provides a focused overview of
plasma-based reconfigurable frequency selective surfaces
(FSS) for adaptive high-power microwave (HPM) shielding.
Unlike conventional metallic FSS, plasma elements
exhibit inherently power-dependent behaviour, enabling
self-actuated reconfiguration without dedicated DC bias
networks. We outline how plasma confined in commercially
available gas-discharge tubes (GDTs) can be modelled as
a dispersive medium, and highlight the key design
levers: collision frequency primarily governs loss and
reflectivity (with reduced pressure improving
selectivity), while electron density drives tunability
toward a highly conductive state.

Building on these fundamentals, two experimentally
validated FSS architectures are presented, supported by
equivalent-circuit modelling and full-wave simulations.
A double-layer GDT-loaded FSS provides a wide, flat-top
bandpass centred at 4 GHz with low insertion loss in the
low-power state, then transitions to strong isolation at
high power due to resonance-driven field enhancement and
plasma ignition. A second, cross-topology
energy-selective surface autonomously shifts its
stopband from 6 GHz (OFF) to 3 GHz (ON) without external
bias. Waveguide measurements up to 50 dBm confirm robust
high-power handling, alongside stable performance under
oblique incidence and pressure-dependent quality factor.
These results position plasma-FSS as a practical route
to adaptive electromagnetic protection for satellite and
aeronautical platforms, telecom infrastructure, and
high-power medical and industrial environments.

This paper presents a reconfigurable tightly coupled
transmit-reflect-array (TRA) antenna for broadband
wireless communication applications. The antenna
features an active unit cell comprising tightly coupled
dipole elements interconnected by PIN diodes and a
polarizer grid for polarization selection, facilitating
1-bit phase reconfiguration. The reflection layer
operates in reflection mode for x-polarized waves, while
the transmission layer operates in transmission mode for
y-polarized waves. By employing different coding
sequences to control the ON and OFF states of the PIN
diodes, the reflection and transmission phases can be
precisely configured, enabling accurate independent beam
steering at desired angles. With an F/D ratio of 0.8 and
a 16×16 element array, the antenna achieves high gain
and low sidelobe levels for both polarization modes.
This reconfigurable TRA antenna is ideally suited for
advanced wireless communication systems requiring
simultaneous dual-mode operation.

This work proposes an ultrathin bandpass
angularselective
surface (ASS). Unlike most previously reported
structures
relying on multilayer configurations, the proposed
design
employs a metallic pattern printed on a single
substrate, resulting
in a significantly reduced profile. The operating
mechanism
is interpreted using an equivalent circuit model in
which the
incident angle is treated as the independent variable to
realize
the desired angular-domain bandpass response. Full-wave
simulations demonstrate that the passive ASS achieves
angularselective
filtering over a wide incidence range within the
operating
band. Moreover, a reconfigurable ASS is realized by
integrating
PIN diodes into the metallic-slot structure, enabling
dynamic
switching between bandpass and stopband states.

This paper presents two reconfigurable antennas loaded
with anisotropic impedance surfaces. The first one
achieves reconfigurable frequency and bandwidth with a
76.6% tuning range in the narrowband mode and 82.9%
bandwidth in the wideband mode. The second antenna
features 360° beam scanning with a step of 11.25° in the
S-band. A semi-analytical mode expansion method is
developed for the inverse-design of these two antennas
by predicting accurate impedance bandwidth and radiation
patterns.

A physics-guided Conditional Variational Autoencoder
(cVAE) framework for the rapid inverse design of
high-aperture-efficiency reflectarray antennas is
proposed in this paper. Addressing the ill-posed nature
of mapping electromagnetic responses to complex
topologies, we incorporate structural symmetry,
manufacturability constraints, and morphological
filtering as prior rules to regularize the unit topology
and enhance dataset quality. A high-precision Residual
Network (ResNet), is embedded into the cVAE loop to
enforce physical consistency, is trained as a forward
proxy to replace time-consuming full-wave simulations.
In this way, model efficiency enhancement is achieved
through the regularized unit design, while antenna
efficiency is ensured by the accurate proxy-constrained
generative model. To validate the method, an 18×18
element reflectarray operating at 10 GHz is designed.
Full-wave simulations demonstrate a realized gain of
23.9 dB, a sidelobe level of −19.6 dB, and an aperture
efficiency of 60.4%. The proposed approach accelerates
design iterations while maintaining engineering
feasibility, providing a practical tool for advanced
metasurface systems.

This invited paper presents our recent progress in
translating semiconductor-grade nano-island-coating
technology into high-value functional materials for 6G
millimeter-wave substrates. The core concept is to
engineer silica-based carrier powder with PVD-based
nanoscale Al-nanoparticle island coating, followed by
controlled conversion into AlN/Al₂O₃
nanoparticle-island-coated fillers. These engineered
fillers are integrated into a non-fluorinated thermoset
composite system to achieve low dielectric constant, low
loss tangent, and improved thermal/mechanical
reliability for high-frequency substrate applications.
By combining powder surface modification, vacuum mixing,
tape casting, and vacuum hot pressing, the proposed
platform provides a practical pathway from
nano-engineered particles to the fabrication of 250 mm ×
250 mm panel-scale substrates with thicknesses ranging
from 100 μm to 100 mm. The target performance of the
developed materials is Dk = 1.6-2.4 and Df < 0.0009
at 10 GHz, making them attractive for advanced RF
packaging, satellite communications, radar sensing, and
future THz devices. This work highlights how a
coating-centered materials platform can bridge advanced
processing, scalable manufacturing, and next-generation
microwave system requirements.

Terahertz technology, characterized by its extensive
development potential and broad application prospects,
has emerged as a significant trend in future
technological development. The radio-frequency (RF)
front – end of a terahertz superheterodyne receiver is
predominantly comprised of a mixer and a local
oscillator (LO). Consequently, the LO, serving as the
core component of the RF front-end, is critical for
ensuring the proper operation of the entire
superheterodyne system. The solid-state terahertz LO,
which typically utilizes a Schottky diode-based
multiplier as its core component, offers notable
advantages such as high reliability, room-temperature
operation, simple architecture, and low cost. These
characteristics have led to its application in various
fields such as meteorological detection, radio
astronomy, and security inspection, solidifying its
status as a vital branch of terahertz source research.
The architecture of a solid-state terahertz LO typically
comprises a pre-stage driver source and a final-stage
multiplier. Given that the driver source, as the initial
part of the entire LO chain, mainly functions to supply
input power to the final – stage multiplier in the
chain, effectively enhancing its output power is of
great significance.
To enhance power-handling capacity and
thermal-dissipation performance, a 120 GHz driver source
based on a GaN monolithic integrated multiplier is
developed. Due to the advantages of GaN material, such
as high thermal conductivity, high voltage withstand
capability and high electron saturation rate, when
utilized in Schottky diodes for frequency doublers, its
defect in electron mobility is avoided. For the research
on the 120 GHz driver source based on GaN monolithic
integrated frequency doubler, a reasonable overall link
composition scheme is proposed. The overall frequency –
generation chain adopts a frequency multiplication
scheme of 10 GHz microwave signals through a x6x2
cascade.
Through an analysis of GaN material properties and their
applicability to doubler design, a novel GaN Schottky
diode design is conceived. The Schottky barrier diodes
applied to terahertz frequency doublers usually have a
relatively high input power, and the internal
self-heating effect is quite obvious. Under actual
operating conditions, material properties such as
electrical conductivity, thermal conductivity, and heat
capacity for each diode layer will change with
temperature. Meanwhile, the internal temperature and
parameters such as current, parasitic capacitance and
parasitic resistance will affect each other. Therefore,
the saturation current and series resistance parameters
in the commonly used SPICE model of Schottky diodes are
not constant, but should be temperature-related
variables. The intrinsic and extrinsic parameters of
Schottky barrier diodes related to temperature change
with the working state, which will have a significant
impact on the I-V characteristics of the diode.
Therefore, the study of the thermal effect of Schottky
barrier diodes cannot be ignored, which is crucial for
improving the accuracy of the Schottky barrier diode
model. To this end, a thermal resistance matrix is
integrated into the diode model. The physical
electrothermal model is composed of the drift-diffusion
equation and the heat conduction equation. Furthermore,
analyze the impact of adjacent metallized components in
the matching structure on heat dissipation.
The design of the 120 GHz monolithic doubler adopts a
balanced circuit structure, mainly consists of WR15
input waveguide, WR8 RF waveguide, GaN Schottky diode,
DC bias filter and matching circuit structure. For the
fundamental frequency matching network, matching
performance is optimized by tuning the lengths of the
reduced-height and reduced-width waveguide sections and
the position of the input short-circuit termination. The
optimal output impedance value extracted from the chip
is substituted into the lumped port of the diode. For
the design of the output end model, the bias circuit
adopts an improved compact microstrip resonator (CMRC)
filter, which has a more compact structure compared to
the high and low impedance filters. This design
effectively confines the second-harmonic signal to the
output waveguide port while preventing it from leaking
from the DC bias circuit, thus meeting the design
requirements.
The measured results demonstrate that incorporating the
thermal resistance matrix into the core diode model
significantly reduced the discrepancy between simulated
and experimental results. Within the frequency range of
109-129 GHz, the maximum output power of the driver
source measured is 35.56 mW. This research provides
beneficial ideas for the manufacturing and design of
Schottky diodes, and also lays a model foundation for
the subsequent realization of high-performance terahertz
frequency conversion devices.

Resonant tunneling diodes (RTDs) can oscillate at
frequencies exceeding 2 THz at room temperature and
generate milliwatt-level output power above 800 GHz. In
the frequency range above 300 GHz, RTDs have
demonstrated relatively high DC-to-RF conversion
efficiency compared with other electronic devices. RTDs
also exhibit unique functionalities, such as
frequency-comb generation and signal detection, which
are useful for terahertz sensing applications. This
paper reviews recent developments in RTD oscillators.

This paper presents a hybrid decoupling strategy that
synergistically integrates defected ground structures
and metallic reflectors to address the strong
long-distance mutual coupling problem in dual-antenna
systems sharing a common ground plane over the 0.8-2.0
GHz band, where surface creeping waves dominate. Through
full-wave simulations, we first characterize the surface
current propagation on the metallic ground plane,
identifying the central region between the two antennas
as the critical coupling path. Based on this analysis,
we design a transverse slotted defected ground structure
(Mode 1) that perturbs the surface current distribution
to effectively suppress low-frequency coupling.
Concurrently, we introduce a folded metallic reflector
(Mode 2) that modifies the propagation paths of
high-frequency spatial waves, enhancing energy
dissipation through reflection and phase manipulation.
The synergistic integration of both mechanisms (Mode 3)
is rigorously validated through full-wave simulations,
demonstrating an average isolation enhancement exceeding
17 dB across the entire 0.8-2.0 GHz band. Our results
reveal the complementary nature of the proposed
approach: the defected ground structure outperforms the
reflector at lower frequencies, while the reflector
exhibits superior decoupling at higher frequencies. The
combined strategy achieves broadband synergistic
decoupling, offering a structurally simple and
cost-effective engineering solution for high-isolation
integration of multi-antenna systems on metallic
platforms.

The rapid growth of 5G/6G, satellite communications,
and AI-enabled edge devices is driving strong demand for
compact, high-efficiency, and scalable antenna
platforms. This presentation presents recent
developments in surface-mounted Antenna-in-Package (AiP)
technologies at MILLIBEAM, focusing on antenna radiation
engineering, low-profile array architectures, RF
materials, and integrated packaging approaches. The
presentation highlights how advanced surface-mounted AiP
platforms can enable intelligent RF systems for
next-generation wireless infrastructure, sensing,
Physical AI, and edge applications through vertically
integrated “Silicon to Intelligent RF Systems” design
strategies.

This paper presents a novel attention-augmented
dual-branch convolutional neural network (DBA-Net) for
classifying monostatic radar cross-section (RCS)
characteristics of six typical artificial structures. A
large-scale dataset is generated by computing
full-azimuth RCS distribution and converting them into
2D heatmaps. The DBA-Net employs dual branches to
extract multi-scale features and a dual-attention
mechanism to focus on discriminative patterns.
Experiments show the model achieves perfect
classification accuracy with rapid convergence,
demonstrating strong robustness and generalizability for
intelligent electromagnetic target recognition.

Accurately and efficiently analyzing the
electromagnetic characteristics of large finite periodic
structures (LFPSs) has always been a challenging problem
in computational electromagnetics. In the past decade,
several artificial neural networks (ANNs) based studies
have been proposed to alleviate this challenge. However,
with the rapid development of quantum technologies, the
performance of ANN-based predictive models still
exhibits significant potential for further improvement.
In this paper, the hybrid quantum model proposed in
previous work is enhanced by incorporating the residual
architecture, enabling more accurate prediction for the
phase of the expansion coefficients in sub-entire domain
basis functions. Numerical experiments demonstrate that
the improved hybrid quantum model exhibits faster
learning capability and higher prediction accuracy.

This paper proposes a learning-driven synthesis
framework for RF transformer-based matching networks
with three-dimensional electromagnetic (EM) structures.
Unlike conventional methods that derive EM structures
from target circuit element values and topologies, the
proposed method directly synthesizes passive networks
from desired performance metrics and given topologies.
Using on-chip transformer impedance matching networks as
a case study, the model first extracts key features from
input impedance and load capacitance via neural networks
to predict initial geometric parameters of the
transformer’s 3D EM structure in 28-nm TSMC CMOS
technology. Subsequently, Bayesian optimization (BO)
refines these geometric parameters for precise
performance tuning. The resulting structures achieve
arbitrary impedance matching while simultaneously
accommodating two load capacitances. As a proof of
concept, multiple transformer designs were synthesized
and validated by Cadence simulations, confirming their
compliance with the targeted impedance characteristics.

Terahertz optical cavity is one of the major elements
to enhance and control the weak interaction between the
atom-thick layer and normal incident terahertz light.
Here we present a hybrid metal-optical Tamm state cavity
with a Nb5N6 microbolometer detector embed, exhibiting a
Q value of 1529 for direct detection. The cavity is
formed by sandwiching a silicon substrate with the
detector between two Si/air distributed Bragg reflectors
(DBR), one of which is capped with an Au layer. The
resonant frequency can be flexibly tuned by adjusting
the substrate’s thickness. The substrate and DBRs can be
fabricated separately and assemble easily, which paves
the way to effectively realize versatile high
performance terahertz devices and strong interaction
between terahertz light and matter.

In this paper, a hybrid chip combining a film bulk
acoustic resonator (FBAR) chip and a glass-based
integrated passive device (IPD) chip is proposed. The
inductors in the hybrid circuit are implemented using
through-glass via (TGV) as vertical spiral inductors.
Such implementation can provide a high-Q inductor
compared to a conventional planar spiral inductor, but
also decrease the influence between the vertically
stacked chips. Compared with the filter chip based on
the same circuit implemented by conventional Si-based
IPD technology, the insertion loss of the hybrid chip is
lower while showing higher integration.

Interdigital capacitors, composed of multiple metal
layers, exhibit superior performance in compact form due
to their high integration. In this paper, a scalable
equivalent circuit model tailored for multilayer
interdigital capacitors is proposed. The circuit
parameters are accurately derived and the
characteristics can be predicted based on the finger
dimensions. The accuracy of the scalable model has been
validated with an accuracy exceeding 92% across a
frequency range of up to 40 GHz. This makes it highly
significant for the modeling of on-chip passive devices.

This talk presents a unified approach to the design and
integration of high-temperature superconducting (HTS)
Josephson mixers across microwave, millimetre-wave, and
sub-terahertz frequencies. A systematic design
methodology is developed, combining circuit modelling,
impedance matching, harmonic mixing techniques, and
experimental validation to ensure predictable and
scalable performance. The study emphasizes the
importance of optimising Josephson junction parameters
and demonstrates how accurate modelling can bridge the
gap between simulation and measurement. Beyond circuit
design, the work introduces advanced integration
strategies, including compact waveguide transitions and
antenna-coupled architectures, enabling efficient
coupling between superconducting devices and radiating
structures. By combining harmonic mixing concepts with
frequency-scanning antenna technologies, the research
establishes a pathway toward compact, low-noise, and
energy-efficient superconducting receiver systems. The
results provide a foundation for scalable HTS mixer
technologies suitable for high-sensitivity
communication, sensing, and imaging applications from
microwave to sub-terahertz regimes.

This paper presents the design of a Ku-band metasurface
antenna for near-field millimeter-wave radar imaging.
The proposed antenna features a three-layer structure.
The slot-coupling feeding network integrating a
Wilkinson power divider is employed to ensure amplitude
and phase consistency across all radiating elements.
Simulation results demonstrate that the antenna achieves
a compact profile with an average gain exceeding 11 dBi
and a 3-dB beamwidth confined within 35º across the
Ku-band, fully satisfying the requirements for
high-precision near-field millimeter-wave imaging, and
the proposed digital imaging system based on metasurface
antenna is expected to play a greater role as a key
solution in next-generation personnel security screening
and non-destructive testing.

This paper presents a fully integrated 30-W tri-mode
gallium nitride (GaN) high power amplifier (HPA)
supporting ultra-wideband (0.03-6.5 GHz),
single-narrowband (SNB) (2.7-3.3 GHz), and concurrent
dual-narrowband (DNB) operation. A dual-path
single-transistor-driven distributed architecture with a
shared-drain artificial transmission line enables
broadband power combination. Frequency reconfiguration
is achieved through gate artificial transmission lines,
while switchable harmonic tuning enhances narrowband
efficiency. The PA achieves over 44.8 dBm saturated
output power across UWB and up to 53% peak
power-added-efficiency (PAE) in SNB mode. Fabricated in
0.25-μm GaN-on-silicon carbide (SiC) process, the design
maintains high efficiency under continuous-wave
operation.

This paper presents a 5-GHz Doherty power amplifier
(PA) implemented in a cost-effective 180-nm 1P6M CMOS
technology with only one ultra thick metal (UTM) layer.
To enable practical integration in legacy nodes with
limited passive quality factors, an integrated
transformer-based triple-coil network is adopted to
realize signal splitting and load combining within a
unified passive structure, reducing interconnection
complexity and layout parasitics.
The PA employs a differential cascode architecture with
double neutralization to enhance gain and stability.
Designed for 5-GHz applications, the simulated results
show a small-signal gain of 12.7 dB, a PSAT of 21.4 dBm,
a PAEmax of 23.0%, and a PAE6dB of 13.8%. The core
circuit area is 1.42 mm2.

A design method for realizing a wideband filtering
power divider (FPD) by adjusting the line-width of the
resonators is proposed in this paper. Due to the
slow-wave characteristic of the D-CRLH resonator, a
compact circuit size is achieved. In addition, a
stopband rejection exceeding 10f0 with a suppression
level of better than 20 dB is realized by cascading a
low-pass structure with the D-CRLH resonator. A wideband
FPD with center frequency of 0.66 GHz and the fractional
bandwidth of 44.2% is designed, fabricated and measured.
The measured insertion loss is less than 4.05 dB and the
isolation between two output ports is better than 21.5
dB from DC to 4.42 GHz (6.7f0). Simulated and measured
results are in good agreement, validating the proposed
approach

While magnetic resonant wireless power transfer (WPT)
offers significant convenience, its performance
typically degrades under misalignments. To address this,
an optimized hybrid multi-coil transmitter array was
designed for enhanced robustness. The proposed approach
optimizes the array topology by removing redundant,
weakly coupled elements and incorporating auxiliary gap
coils to bridge magnetic nulls. This structural
refinement not only intensifies the magnetic field but
also achieves a more uniform field distribution.
Simulation results indicate that the proposed WPT link
delivers a power transfer efficiency of 81% at a
transfer distance of 30 mm, exhibiting high tolerance to
lateral and angular offsets. This compact transmitter
configuration provides a practical solution for
maintaining high-efficiency power delivery in
misalignment-prone near-field charging scenarios.

The up-conversion spread spectrum module, which can
shift low-frequency signals to extremely high
frequencies within the usable bandwidth, is a critical
hardware component for enabling next-generation
high-capacity communications, high-rate sensing, and
other cutting-edge applications, and is of great
significance to modern communication. As the application
frequency of electromagnetic waves extends into the
millimeter-wave and even terahertz bands, the
requirements for signal sources as signal testing
instruments are also gradually increasing. There is an
urgent need to extend measurement frequencies to higher
bands, which can be achieved by integrating an
up-converter at the front end of the system. This paper
conducts research based on up-conversion technology for
50GHz to 75GHz broadband signals. Several key devices in
the frequency conversion system were developed,
including a wide-stopband waveguide filter for splitting
the 50GHz to 110GHz signal and suppressing image
frequency signals, and a local oscillator based on a
frequency multiplier and amplifier module. A 50GHz to
75GHz broadband signal up-conversion system was also
constructed to down-convert a 28.95GHz to 30.15GHz
broadband signal to the 50GHz to 75GHz range.
Experiments show that the output power of the
up-converted signal is not less than 13 dBm, the link
gain is not less than 20 dB, and the output spurious
suppression is greater than 40 dBc, meeting the system
specifications.

This paper presents a formula-based synthesis and
design method for bias tees capable of superimposing
low-frequency AC signals onto DC path while maintaining
sharp frequency selectivity. By modeling the bias tee as
a parallel connection of lowpass and highpass sections,
closed-form expressions are derived to directly relate
the element values of the RF path highpass section to
those of the DC path lowpass section, allowing
systematic circuit synthesis with reduced design
complexity. The proposed approach enables the
introduction of finite-frequency transmission zeros,
resulting in a steep skirt response beyond those of
conventional first-order bias tees. The fabricated
prototype demonstrates an RF insertion loss better than
1 dB above 2.7 GHz and maintains acceptable matching.

This paper focuses on the transient
electromagnetic-thermal-fluid coupling analysis of
microchannel cooling in electronic packages using the
finite difference method. Complex geometric models are
comprehensively modeled and analyzed, with numerical
discretization and iterative computation implemented
through the finite difference scheme. The effectiveness
and efficiency of the proposed method are validated
through case studies and
comparisons with the commercial software COMSOL.

In this work, a physics-informed attention network
(PIAN) is proposed for the rapid analysis of scattering
problems in large-scale finite periodic structures
(LFPSs). The encoder captures the relationship between
array features and global coupling with self-attention
mechanism, which guides the decoder to generate the
final current coefficients of LFPSs based on the NASED
initial current coefficients with cross-attention
mechanism. The introduction of initial current
coefficients enables the characterization of cell
structure for different cells. The well-trained network
can generalize to various cell structures, which
significantly reduces the cost of dataset generation.
Numerical experiments validate the accuracy,
generalization capability, and efficiency of the
proposed method.

This paper proposes a fast solution method to analysis
the electromagnetic scattering characteristics of the
complex electromagnetic structures with lossy dielectric
materials. In this method, the characteristic mode (CM)
formulation for complex electromagnetic structures with
lossy dielectric materials is first established based on
the energy theory and the surface integral equation.
Utilizing the modal reconstruction property of the
theory of characteristic mode (TCM), the surface induced
electromagnetic currents of individual array elements
are accurately solved, and the scattering fields are
obtained. The scattering field of the array is then
rapidly acquired through phase superposition, enabling
the calculation of RCS. Numerical examples demonstrate
that the proposed method significantly reduces
computation time and memory overhead while maintaining
accuracy.

In indoor Radar Cross Section (RCS) test ranges,
multipath signals generated by reflections from fixed
structures such as walls and ceilings severely
contaminate the true measured values of targets. This is
particularly prominent in low-frequency band
measurements and for low-RCS targets. Traditional
background subtraction or time-gating methods often fail
to isolate interference that is coherent or closely
spaced with the target echo. To effectively suppress
background clutter in indoor testing environments, this
paper conducts an in-depth study on background
separation and cancellation techniques. A
target-background coupling model based on the Target
Translation Processing (TTP) method is proposed. By
utilizing a single translation of the target between two
measurements, the phase of the multipath signal is
actively altered, thereby achieving the separation of
the target echo from the background multipath at the
signal level. Simulation analysis determines that the
optimal translation range is between 0.2λ and 0.3λ to
minimize the ill-conditioning of the solution matrix.
Experimental results on a flat plate demonstrate that
the proposed algorithm can effectively suppress
significant false interference peaks introduced by fixed
wall reflections in the expected multipath directions,
significantly improving the accuracy of target
measurements and recovering the true RCS
characteristics.

The Efficiency Maximum Multiple-Input Multiple-Output
(E-MIMO) approach has recently been proposed as an
effective beamforming technique for array antennas [1].
Practical implementation of E-MIMO requires accurate
knowledge of the coupling matrix between transmitting
and receiving elements, typically represented by the
S-parameter or Z-parameter matrix. In realistic
environments, however, direct measurement of the full
multi-port matrix is time-consuming and often difficult,
particularly when the receiving antennas are located far
from the transmitting antennas. This paper proposes a
method for estimating the coupling matrix using pilot
signals. In the proposed approach, the mutual admittance
or impedance matrix between the transmitting and
receiving ports is derived from measured port voltages
under known termination conditions at the transmitting
side induced by pilot signal excitation. Numerical
simulations are conducted to validate the proposed
estimation method.

Passive radar is a type of radar system that offers
several advantages over traditional active radar
systems. Unlike active radar, passive radar does not
require a dedicated transmitter and instead uses
existing signals from the environment, like radio or
television signals as a source of illumination, making
it low cost, low power and portable.
With advancements in receiver technology and
computational power, passive radar has become an
increasingly attractive option in many applications
where active radar would have been used. However, the
detection range and accuracy of passive radar are
limited by the geometry of a single receiver scenario
and the signal-to-noise ratio of the received signal.
One way to overcome these limitations is to use multiple
receivers to triangulate the position of a target, which
provides increased coverage and the ability to detect
smaller targets.
To fully make use of the signals, coherent detection
provides the opportunity to maximally combine the
signals from all of the receivers. However, this depends
on accurate synchronisation between receivers. In
practice, this is challenging, as differences in
receivers caused by both manufacturing defects as well
as temperature fluctuations, can degrade the level of
synchronisation.
This work investigates the effect of synchronisation
through experimental modelling of RF receivers and then
looks at how these effect radar signal processing in
terms of localisation performance in a virtual radar
environment. Using the Generalised Canonical Correlation
Analysis (GCCA) detector, a high-performance coherent
detector is used. The key output of this work
demonstrates that synchronization errors significantly
affect localization performance, particularly where the
detection performance is relying on coherent detection.
However, when conditions, particularly temperature,
remain stable, a calibration process can be used to
mitigate most of the error.
Understanding the impact of synchronization errors is
crucial for improving and developing future
multi-receiver passive radar and distributed beamforming
systems.

Electrically large phased arrays for satellite
communications often exceed anechoic-chamber (AC)
test-zone dimensions, motivating subarray-based pattern
reconstruction realized through subarray stitching for
OTA characterization. However, conventional stitching
tiles an isolated-subarray pattern and implicitly
assumes identical embedded behavior across the aperture.
This assumption produces systematic boundary-induced
errors that accumulate in the reconstructed pattern,
particularly at wide zenith angles. This paper proposes
a multi-template differential correction method that
uses one isolated subarray and four representative
embedded templates (middle, two edges, and one corner).
The method models template deviations as differential
fields, propagates them across the aperture via symmetry
mapping, and applies an angle-dependent least-squares
weight for direction-selective compensation. Numerical
simulations show up to a 53% reduction in full-angle
gain MSE and a 65% reduction in wide-zenith MSE,
validating improved wide-angle reconstruction under
test-zone constraints.

A multi-material additively manufactured wideband
dual-linear polarized (dual-LP) antenna with high
isolation is proposed in this paper. The structure
integrates a magnetoelectric-dipole (ME-dipole) and a
quasi-Yagi antenna. The ME-dipole utilizes a
slot-coupled feed to produce horizontal polarization
(HP), while the quasi-Yagi features two pairs of
symmetrical dipoles with obliquely angled feed lines to
realize vertical polarization (VP). The antenna is
realized using multi-material additive manufacturing in
a single integrated process, resulting in a highly
compact design. Simulation results demonstrate that the
antenna achieves a shared impedance bandwidth (IMBW) of
48.71% in the millimeter-wave (mm-wave) band, while
maintaining an isolation level below −34.5 dB. Owing to
its compact configuration, wide bandwidth, and high
isolation, the proposed antenna is well-suited for a
variety of modern communication and sensing
applications.

Owing to their short wavelength and light-like
propagation behavior, terahertz waves require
quasi-optical components to control the flow of
radiation. To meet this need, 3D-printing has evolved
over the past decade from a niche technique to a highly
customizable, general-purpose methodology to produce
terahertz quasi-optics, using consumer-grade hardware.

This work presents a layout-only phase-tapered bus
bar combiner for Gallium Nitride (GaN) MMIC power
amplifiers (PAs) in foundry compatible form. The
approach
improves power-added efficiency (PAE) by introducing
asymmetry in drain-feed without increasing circuit
complexity or addition of extra components. A graded
drain
feed taper is used to introduce controlled phase delays
of 18.2°
for the edge devices, 7.1° for second-edge devices and
less than
1° for center devices at 4.65 GHz. This results in 12.5
percent
reduction in DC current while maintaining excellent
vector
combining efficiency (ηcomb= 99.2 percent). Second, a
single
output-per-four-transistor topology reduces the required
impedance transformation thus lowering the matching loss
as
well as avoiding closed metal loops. EM co-simulations
carried out using UMS GaN technology (0.25 µm) with
eight
GH25-10 HEMTs (total periphery of 20 mm) results in a
PAE
of (44.5-46.3) percent in CW mode (improved by 5-points
over conventional bus-bar), an output power of 47.6W and
(21-22.7) dB of gain with a negligible linearity
degradation
over (4.35-4.97) GHz.

This study explores the use of surface acoustic wave
(SAW) phononic crystals (PnCs), specifically square
pillar-based PnCs reflectors in SAW resonators. The PnC
generate acoustic band gap that reflects the wave to the
resonator body, which enhances the stored energy and
Bode Q in comparison to a traditional reflector. In this
work, we propose a square-shaped titanium PnC
implemented on a 15 ° Y-X LiNbO₃/SiO₂/Si layered
substrate. The proposed design generates a wide acoustic
bandgap that. To evaluate the practical impact of PnCs
in SAW devices, two SAW resonators employing PnC and
reflector designs are compared and analyzed. From the
simulated frequency responses, we find that using the
Square-PnC as the reflector reduces resonator energy
loss and enhances the stored energy

In this work, we propose and demonstrate an S-shaped
Mach-Zehnder modulator (MZM) on a silicon substrate. As
global data traffic demands surge, thin-film lithium
niobate on silicon has emerged as a premier platform due
to its high electro-optic coefficient and seamless
integration with CMOS-compatible processes. However,
conventional straight-path traveling-wave electrodes are
often limited by severe conductor losses and velocity
mismatch at millimeter-wave frequencies. By utilizing an
innovative S-shaped topological layout, we effectively
mitigate microwave transmission loss by alleviating
high-frequency current crowding at the electrode edges.
This geometry also provides the added benefit of
increasing the optical group index, thereby enhancing
both velocity matching and modulation efficiency. We
fabricated a prototype with a 5 mm interaction length,
and experimental results-which align well with numerical
simulations-show a 1 dB reduction in electrode loss
compared to traditional straight-path designs of the
same length. Consequently, the device achieves a record
EO bandwidth exceeding 110 GHz. This silicon-based
S-shaped MZM offers a high-performance and scalable
solution for the next generation of ultra-broadband
photonic integrated circuits.

There is a growing interest in spectrometer-based
techniques to measure and characterise particulate media
across diverse fields, including medicine, environmental
monitoring, and manufacturing. Spectrometers provide
broadband measurements in a non-destructive manner,
potentially enabling the extraction of rich spectral
information that can enhance the characterisation of the
medium. In this paper, we present a new dataset of
transmission measurements through dynamic dust clouds
acquired using an optoelectronic frequency-modulated
continuous-wave (FMCW) spectrometer. The experimental
results demonstrate that simultaneous broadband
magnitude and phase measurements enable the estimation
of the effective refractive index of the particulate
air-dust mixture. These findings highlight the potential
of FMCW spectrometry for quantitative characterisation
of dynamic mediums.

Metasurface inverse design usually relies on numerical
targets and therefore cannot directly use
natural-language requirements. The inverse mapping from
spectra to structural parameters is also non-unique. To
address these issues, we propose a semantics-guided
cross-modal framework for intelligent design of
high-performance metasurface absorbers. The framework
combines vision-language alignment, forward surrogate
modeling, and probabilistic inverse design in a unified
pipeline built on a four-modal dataset. Specifically, we
use a CLIP-based module for text-spectrum alignment, a
spatially varying multi-channel attention Fourier neural
operator for forward prediction, and a mixture density
network for inverse design. The forward model achieves
(R^{2}=0.9954) on the test set and (R^{2}=0.9939) on the
validation set. The inverse model achieves MAE =
0.024855, RMSE = 0.046434, and (R^{2}=0.960359), while
the semantic alignment module reaches (88.24%) Top-1
accuracy and (100.00%) Top-5 accuracy.

The terahertz frequency band offers great potential for
ultrahigh-speed wireless communications and
high-resolution sensing in 6G and beyond systems.
However, compact and scalable terahertz frontends are
still limited by the lack of a unified integration
platform that supports both low-loss propagation and
efficient active devices. In this work, we present a
photonic-electronic co-integration framework combining
effective medium silicon waveguides with resonant
tunneling diodes. The platform enables low-loss,
broadband propagation and compact nonlinear
functionalities, including oscillation, detection, and
phase control. Integrated transceivers and
beam-steerable antennas at the 300-GHz band are
demonstrated. This approach can be expected to promise
fully integrated, reconfigurable terahertz frontends for
next-generation communication and sensing systems.

THz applications have been increasing over the years.
These applications include both space-based remote
sensing as well as ground-based industrial applications
such wireless communications. For communication systems,
the THz frequency range is attractive as it provides
larger bandwidth and smaller apertures. This talk will
focus on the recent advancement in the development of
room-temperature based wideband, compact sources and
detectors in the THz range for space communication
systems.

Terahertz sensing is often cited as a transformative
solution for non-destructive evaluation, offering
millimeter-scale spatial resolution and unique
see-through capabilities. Despite the availability of
various photonic and electronic systems, significant
challenges remain. Photonic-based systems are often
hampered by inherent laser drift and phase noise, while
electronic systems suffer from phase noise amplification
through high-order frequency multiplier chains. These
issues compromise sensitivity, which is typically
improved through temporal averaging at the expense of
measurement speed. Furthermore, high-performance
components remain costly and delicate, whilst their
limited output power often restricts the effective
sensing range. Sensitivity can be dramatically enhanced
by comparing the probe signal with a reference of the
original carrier, a technique known as self-homodyning.
In this presentation, we discuss two quadrature (I/Q)
self-homodyne detection systems operating around 300
GHz, a strategic band for extended-range sensing due to
minimal atmospheric absorption. One architecture
utilizes I/Q interferometry, while the other employs I/Q
mixing. Both systems achieve nanometer-scale vibration
sensitivity with a theoretical measurement bandwidth
reaching gigahertz rates. This detection scheme
suppresses both external noise and source phase noise,
enabling the use of high-power terahertz oscillators to
further extend sensing range. We will demonstrate
successful applications in acoustic eavesdropping,
non-contact chip sensing, and vital-sign detection.
assumption.

Energy efficient materials, devices, technologies and
systems will play a major role with the evolution of
sensing and communication network architectures in the
AI era. The progress in compound semiconductor devices
combined with silicon technologies and 3D heterogeneous
integration (3DHI) are defining the microelectronics
future in the industry.

This talk will present the recent advancements in
semiconductor and microelectronics integration
technologies. The challenges and opportunities of the
system-oriented compound semiconductor-based
microelectronics in the Agentic AI era will also be
discussed.

Millimeter-wave (mm-wave) and sub-terahertz (sub-THz)
frequencies are key technologies for future wireless
systems such as 6G, enabling ultra-high data rates and
massive connectivity. However, implementing
reconfigurable RF components at these frequencies
remains challenging because conventional semiconductor
switches suffer from parasitic effects and performance
degradation. Phase-change materials such as vanadium
dioxide (VO₂) offer a promising alternative due to their
reversible insulator-metal transition and large
resistance change.

This work explores screen-printed VO₂ switches as a
scalable platform for reconfigurable antenna and
metasurface applications across microwave, mm-wave, and
sub-THz frequencies.

First, a frequency-reconfigurable metasurface absorber
is proposed using a large-area VO₂ layer integrated with
a resistive metasurface pattern. Unlike conventional
designs that require discrete RF components, the
proposed structure achieves dynamic switching of
absorption bands by modulating the sheet resistance of
VO₂, demonstrating a simple and scalable approach for
reconfigurable metasurfaces.

Second, a screen-printed VO₂-based intelligent
reflective surface (IRS) operating at 100 GHz is
demonstrated for sub-THz wireless communication. The IRS
employs high phase-changing-ratio VO₂ switches to
control the reflection phase and beam direction,
enabling large-area beam steering while avoiding the
parasitic limitations of conventional semiconductor
switching devices.

Third, a VO₂-switched leaky-wave antenna operating in
the V-band is presented to realize reconfigurable beam
steering in mm-wave antenna systems. By switching the
VO₂ elements between insulating and metallic states, the
antenna dynamically alters its phase constant and
radiation characteristics, enabling distinct
beam-scanning behaviors within the operating band.

These three demonstrations collectively show that
screen-printed VO₂ switches enable low-cost, large-area,
and parasitic-free reconfigurable electromagnetic
structures, highlighting their strong potential for
adaptive antennas and metasurfaces in future mm-wave and
sub-THz communication systems.

This paper presents the Meta-Screen, a novel
reconfigurable indoor partition for full-space
millimeter-wave environment control. Utilizing a highly
integrated Rx-Gnd-Tx unit cell with only two PIN diodes,
the proposed architecture achieves 1-bit phase
quantization for both transmission and bi-directional
reflection modes. Simulations show wide fractional
bandwidths of 27.1%, 23.8%, and 8.3% for transmissive,
+z-reflective, and -z-reflective modes, respectively,
with a common operational bandwidth of 4.1%.
System-level validation of a 14×14 array at 24 GHz
confirms robust beam-scanning up to 60° and peak gains
of 17.94 dBi. This design offers a low-complexity,
high-efficiency solution for 360° coverage in future 6G
smart radio environments.

This paper proposes a low-rate digital predistortion
(DPD) technique. In this DPD technique, a
switch-estimated method is applied to estimate the power
amplifier (PA) output signal with low-complexity model
extraction iteratively by a single real undersampling
feedback signal. Furthermore, the band-limited DPD model
is used to reduce the sampling rate of digital-to-analog
converters (DACs). A 400 MHz 5G NR signal at the center
frequency of 3.6 GHz is used to verify the proposed
technique. The measurement results show that the
proposed DPD technique can effectively reduce the
hardware resources consumed during the model extraction
process while maintain good linearization performance.

This work presents a 15-40 GHz ultra-broadband metalens
based on height-controlled meta-atoms and compatible
with hybrid-material 3D printing fabrication. The
proposed three-dimensional meta-atom introduces an
additional vertical degree of freedom that governs
multi-order mode evolution within the unit cell. By
tuning the structural height, the evolution and
interaction of higher-order modes are controlled,
enabling effective phase control over a broad frequency
range. Unlike conventional planar phase-shifting
elements that rely primarily on two-dimensional
geometric variations, the proposed 3D configuration
leverages vertical structural modulation to extend the
operational bandwidth while maintaining phase
tunability. A prototype is fabricated and experimentally
validated. Measured results demonstrate broadband
operation from 15 to 40 GHz with a peak gain of 25.3 dBi
at 25 GHz, corresponding to approximately 90% relative
bandwidth. The proposed design provides a manufacturable
route toward ultra-broadband metalenses.

This paper presents a switchable dual circularly
polarized (CP) 4×4 patch array system for CubeSat
communications. The CP element uses a slot-coupled feed
to achieve wideband matching and a low axial ratio (AR).
A mirror transformed element is employed to realize
right-hand circular polarization (RHCP) and left-hand
circular polarization (LHCP) with similar performance. A
sequential rotation feeding (SRF) network is used in the
4×4 arrays to improve the impedance and AR bandwidths.
Simulation results show that the 4×4 RHCP and LHCP
arrays achieve an overlapped bandwidth (|S11| < −10
dB, AR < 3 dB) of 48.7% (28.4-46.2 GHz), with
realized peak gains above 16.6 dBic. Finally, the RHCP
and LHCP arrays are collocated on the CubeSat top panel,
providing a compact switchable dual CP antenna system
for polarization diversity and reduced polarization
mismatch.

A pattern-reconfigurable metasurface is proposed, which
enables dynamic switching between Orbital Angular
Momentum (OAM) vortex beams and dual-beam radiation
patterns. The proposed metasurface is constructed using
a multi-layer Printed Circuit Board (PCB), with its
aperture phase distribution determining the radiation
characteristics. The phase distribution for
x-polarization consists of focusing phase and vortex OAM
phase, while that for y-polarization comprises focusing
phase and a periodically alternating phase of 0° and
180°. Simulation results demonstrate that the proposed
metasurface can efficiently achieve dynamic switching
between an OAM beam with a topological charge of 1 and
dual-beam patterns.

A textile antenna with dual-band dual-mode operation is
proposed for on- and off-body communications. An
omnidirectional radiation pattern is achieved by loading
shorting pins to excite the TM00 mode at the 2.45-GHz
band for on-body communication, while a broadside
radiation pattern with high gain is realized by etching
slots to modify the TM30 mode at the 5.8-GHz band for
off-body communication. Both bands can be tuned
independently. A prototype was fabricated using textile
materials, allowing it to conform to the human body. The
measured results indicate that the antenna can fully
cover the 2.45- and 5.8-GHz WBAN bands, achieving
measured peak gains of 1.31 dBi in free space and -1.09
dBi on a three-layer human tissue model for the 2.45-GHz
band, as well as 9.97 dBi in free space and 9.62 dBi on
the phantom for the 5.8-GHz band. The demonstrated
properties confirm that the proposed antenna is suitable
for wearable applications.

A compact wideband dual-circularly polarized (dual-CP)
antenna with isolation enhancement is proposed in this
paper. First, a compact antenna element is designed,
exhibiting a 27.66% dual-CP bandwidth in the Ka-band. By
employing a downward-folded electric-dipole (E-dipole),
the footprint of the antenna is significantly reduced,
leading to a highly compact structure. However, the
isolation between the two ports is low, reaching only
6.5 dB across the operating bandwidth. To address this
issue, two dielectric layers are introduced above the
radiator, with a cavity etched in the center of the
lower dielectric layer. With the cavity-loaded
structure, the port isolation is improved by up to 15
dB. Owing to its wideband dual-CP, compact
configuration, and high port isolation, the proposed
antenna element is well suited for satellite
communication antenna arrays.

This paper presents a novel circularly polarized
coplanar waveguide (CPW)-fed antenna designed for
integration into vehicle roof glass for satellite
navigation applications. The antenna utilizes an
asymmetric ground plane to achieve broadband circular
polarization. A key feature is the seamless integration
of a coplanar frame structure within the blackout border
region of the roof glass, which effectively suppresses
surface wave propagation. Measurement results
demonstrate that the prototype achieves an impedance
bandwidth of 36.04% (1.16-1.67 GHz) and a 3-dB axial
ratio (AR) bandwidth of 34.29% (1.16-1.64 GHz).
Furthermore, the antenna exhibits a boresight right-hand
circularly polarized (RHCP) gain exceeding 2 dBic across
the B3 and L1 navigation bands. These characteristics
satisfy the stringent requirements for modern automotive
Global Navigation Satellite System (GNSS) antennas.
Keywords-Broadband, circular polarization, CPW feed,
surface wave suppression, GNSS application

This paper proposes a low profile and high
front-to-back ratio millimeter-wave array based on
electromagnetic bandgap ground (EBGG). The proposed
array consists of two SIW slot antenna elements
operating in the 24 GHz ISM band. In order to enhance
gain and the front-to-back ratio (FBR), a π-shape EBGG
is introduced on both sides of the array, while
maintaining an ultra-low profile of only 0.04λ0.
Compared with the original array, the peak realized gain
of the proposed array is enhanced from 8.0 dBi to 9.0
dBi at 24.0 GHz, a reduction in the 3-dB beamwidth from
105° to 91°, and a significant enhancement in FBR from
17.34 dB to 30.17 dB. These results demonstrate that the
proposed π-shape EBGG is an effective solution for
achieving gain and FBR enhancement in low-profile
millimeter-wave antenna arrays.

This paper presents a millimeter-wave (mmW) rotary
traveling-wave oscillator (RTWO) integrating distributed
varactors and common-mode high-impedance techniques to
mitigate dispersion-induced flicker noise upconversion.
Fabricated in TSMC 65nm CMOS, the 16-phase RTWO achieves
a tuning range from 19.3 GHz to 23.7 GHz with phase
noise of −130.2 dBc/Hz at 10-MHz offset. With a power
consumption of 9.6mW, peak Figure-of-Merit (FoM), FoMT
and FoMP reach 187.8, 193.9, and 199.9 dBc/Hz,
respectively.

This paper proposes a dual-core series resonance
voltage-controlled oscillator (SRVCO) designed for
wideband communication applications. The dual-core SRVCO
topology is utilized to achieve a wide tuning range
(TR), significantly lower the power consumption of SRVCO
while still maintaining a decent PN and FoM performance.
By manipulating the coupling coefficient between the
primary and secondary coils of the transformer, mode
ambiguity is eliminated. Implemented in TSMC 28-nm bulk
CMOS process, the VCO achieves a simulated continuous
oscillation frequency range of 8.8 to 12.5 GHz (tuning
range of 34.7%). This SRVCO operates at a 0.7 V supply
with a power consumption of 13.1 mW. The simulated
results demonstrate a best phase noise of -137.8 dBc/Hz
at 10-MHz offset, corresponding to a figure-of-merit
(FoM) of 190.5 dBc/Hz and a FOM of tuning range (FoMT)
of 201.3 dBc/Hz.

Broadband and multiband antenna decoupling is often
associated with the joint contribution of multiple
characteristic modes. This paper presents a
super-mode-group (SMG) framework for reduced-order
analysis of symmetric multi-mode antennas. Starting from
the characteristic-mode expansion of the port admittance
matrix, the relevant modes are grouped into odd and even
groups according to structural symmetry. Two grouped
descriptors, namely the total excitation weight and the
weighted modal eigenvalue, are introduced to describe
the overall contribution of each group. The formulation
shows that decoupling is favored when the odd and even
groups remain balanced in grouped-power/conductance
contribution and synchronized in near-resonant behavior.
Numerical parametric results support this
interpretation. The framework provides a reduced-order
view for symmetric multi-mode antenna analysis.

For millimeter-wave applications in short-range
wireless communication, this paper proposes an LNA based
on a three-stage cascode. To expand the input-matching
bandwidth, the input-matching network introduces another
pole at a higher frequency, thereby achieving a wider
S11 bandwidth. Moreover, two transformers were used to
connect the transistor drain in the previous stage to
the transistor source in the subsequent stage. This
enables the transistor to exhibit enhanced conductivity
in the latter stage, thereby increasing its gain. The
increase in gain suppresses noise. Under a 1V power
supply, the power consumption is 17.6mW. This low-noise
amplifier has a peak gain of 21.1 dB at 61.1 GHz within
a 3-dB bandwidth of 45.7-68.9GHz and achieves the lowest
noise of 3.67dB at 55.9GHz. Meanwhile, this LNA is
unconditionally stable across the entire frequency
range. The area of this LNA is 0.17mm2.

As the input power of rectifiers decreases to below -30
dBm, the rectifier exhibits a highly capacitive complex
impedance, leading to a dramatic increase in power loss
within the impedance matching network during energy
transmission. To minimize the equivalent series
resistance (ESR) of the matching structure, this paper
proposes a low-ESR distributed spiral inductor, which is
synergistically integrated with a T-junction microstrip
structure to construct the matching network. Compared to
the conventional impedance matching networks, this
structure effectively minimizes parasitic ohmic losses
within the matching network, achieving higher power
conversion efficiency. Simulation results demonstrate
that at an operating frequency of 900 MHz and an input
power of -35 dBm, the rectifier circuit utilizing the
proposed matching network achieves a power conversion
efficiency (PCE) of approximately 10.97%.

The wideband impedance mismatch is main critical
challenge to improve the efficiency. This paper presents
a multi-mode tunable matching network. The matching
performance can be improved with the flexible
combination of tuning excitation modulus and phase.
Across the 0.1-10 GHz range, the return loss is less
than 10 dB. The prototype occupies an area of only
200×140μm².

To address the limitations of conventional lumped
element matching networks in broadband applications,
this paper
investigates the broadband mechanism and tuning
characteristics of magnetically coupled matching
networks. Based on a tunable transformer structure, a
matching network with adjustable bandwidth and ripple is
proposed. The frequency and impedance tuning mechanisms
of in-phase and out-of-phase configurations are
systematically analyzed, thereby extending the
theoretical framework of magnetically coupled matching
networks.

This paper presents a 6.425-7.125 GHz filtering power
amplifier (FPA) implemented using a 0.1-um GaAs pHEMT
process integrated with glass-substrate inte-grated
passive device (IPD) technology. A two-stage
architecture is adopted, where multiple transmission
zeros are introduced to realize a bandpass filtering
response. To minimize insertion loss, the output
match-ing network (OMN) is fabricated using high-Q
through glass via (TGV) IPD technology. Simulation
results show that the proposed PA achieves a gain of
20.5-21 dB over the frequency range of 6.425-7.125 GHz
with a strong out-of-band rejection. The output power
reaches 32.2-32.9 dBm with a saturated power-added
efficiency (PAE) of 46.5-49.5%.

This paper presents a novel wideband phase shifter (PS)
architecture featuring a dual-state multi-resonator
response, where both states integrate an admittance
inverter (J-inverter) model with lossy coupling. In
addition, the transistors are not only used as switches
but also reused to form the resonators. Implemented in a
0.25-μm GaAs IPD process, a representative 90° PS is
designed for the 22-32 GHz band. Post-layout
electromagnetic simulations demonstrate a phase shift of
91.5° ± 1.5°, a maximum insertion loss of 3 dB in both
states, and an amplitude imbalance below 1 dB. The
proposed architecture provides a compact and robust
solution for millimeter-wave phased-array systems.

This paper presents a metasurface design that
integrates polarization conversion and reconfigurable
frequency selective surface (FSS) technologies to
achieve ultra-wideband radar cross section (RCS)
reduction with a continuously tunable transmission
window. The structure comprises a tunable low-frequency
polarization conversion metasurface (PCM) loaded with
varactors and resistors, a high-frequency PCM
orthogonally stacked to avoid Fano resonance, and a
reconfigurable FSS. By adjusting varactor capacitance,
the transmission window can be tuned from 4.6 GHz to 7.1
GHz with insertion loss <1 dB, while maintaining
polarization conversion absorption ratio (PCAR) >0.9
in stopbands. A checkerboard array achieves >10 dB
RCS reduction from 5 GHz to 26 GHz (135.5% bandwidth).
This design offers unique flexibility for adaptive
stealth antennas.

Metal additive manufacturing has emerged as a
transformative fabrication technique for microwave and
millimetre-wave waveguide components, yet challenges
persist due to degrading surface conductivity from high
surface roughness, particularly in low-conductivity
metals and alloys. Copper is one of the most
electrically conductive metals. Its nominal bulk
conductivity is 53% higher than aluminium. However,
copper printing is not as well developed and utilised
due to process difficulties that arise from the poor
absorption of infrared laser commonly used in Laser
Powder Bed Fusion (L-PBF) Additive Manufacturing (AM).
This work investigates the application of pure copper
printing to waveguide devices. A monolithic copper
waveguide bandpass filter is fabricated using L-PBF
technology, leveraging copper’s superior electrical and
thermal properties for high-power microwave
applications. This filter employs a step-impedance
low-pass design and exploits waveguide cut-off
characteristics for passband frequency selectivity. The
filter is designed for Q-band ground segment network
applications, with a passband from 37.5 to 42.5 GHz.
Optimized L-PBF processing parameters overcome copper’s
high reflectivity to infrared laser. RF measurements
show excellent agreement with simulations, yielding a
0.45 dB insertion loss and an 18 dB worst-case return
loss, with minimal frequency shift confirming high
manufacturing accuracy. This study demonstrates the
potential of copper 3D printing for waveguide filters.

This paper presents a method for designing a broadband
unequal power divider to achieve an arbitrary
power-dividing ratio. The divider is realized by
reducing the height of the narrow edge of a waveguide,
without affecting the phase consistency between the two
output ports. Formulas for determining the power ratio
and a design methodology to compensate for
discontinuities in the waveguide-using irises, a septum,
and a matching section-are introduced. Moreover, a 2:1
unequal power divider operating in the frequency range
of 25-31 GHz is designed and fabricated. The measured
bandwidth is approximately 21%, featuring an input
return loss exceeding 25 dB, an insertion loss below
0.15 dB, and a phase difference between the output ports
of less than 5°.

This paper presents the design and cryogenic
characterization of on-chip millimeter-wave
ultra-wideband (UWB) bandpass filters (BPFs) optimized
using advanced algorithms. First, an on-chip mm-wave UWB
BPF is designed, which demonstrates a 0.12 dB insertion
loss improvement and a 0.3 GHz frequency shift when
cooled from 300 K to 77 K. Based on this design, a
flip-chip InP-based balanced UWB BPF utilizing
electromagnetic-circuit co-optimization with the grey
wolf optimization (GWO) algorithm is designed. The
filter is fabricated with spiral inductors and
metal-insulator-metal capacitors on an alumina
substrate, and maintains stable differential mode
performance (center frequency: 15.45 GHz, bandwidth:
101.9%, common mode rejection: 20 dB over 0-24.5 GHz)
across 300 K, 70 K, and 5 K. Notably, the minimum
insertion loss decreases from 1.02 dB to 0.72 dB when
cooled from 300 K to 70 K, with 0.3-0.8 dB improvements
across the passband. Analysis reveals that enhanced gold
conductivity at cryogenic temperatures is the primary
mechanism for insertion loss reduction, significantly
exceeding the adverse effects of dielectric loss and
structural deformation. The GWO algorithm successfully
extracts equivalent circuit parameters, enabling
temperature-dependent performance prediction for
cryogenic mm-wave applications.

This paper proposes a design scheme for a broadband
highly selective bandpass filter branch line coupler
(BHFC) applicable to the C-band. By integrating a
broadband coupling structure-comprising parallel
coupling lines, high-impedance transmission lines, and
parallel open-circuit branch lines-at each port of a
single-section branch line coupler, it achieves bandpass
filtering characteristics with excellent selectivity and
a wide operating bandwidth. The circuit design has been
validated through electromagnetic simulation.
Experimental results demonstrate an operating frequency
range of 4.02 GHz to 7.88 GHz, with a relative bandwidth
reaching 64.9%. The power imbalance is ±0.6 dB, return
loss exceeds 13 dB, phase imbalance is ±6.6° and
selectivity exceeding 73.2%.

This paper presents an ultra-high-sensitivity microwave
planar sensor for biological permittivity sensing based
on a conductor-backed coplanar waveguide (CPW)
integrated with a modified complementary electric-LC
(CELC) resonator. The proposed structure incorporates
meandered frames and an interdigital capacitor (IDC)
into the CELC resonator etched on the bottom ground
plane to enhance the effective inductance and
capacitance of the resonant structure. The proposed
sensor achieves peak and average sensitivities of 3.58%
and 2.58%, respectively, demonstrating its potential for
biological permittivity sensing applications.

We present the integration of phase transition
materials -PTM (e.g. VO2) with volatile metal-insulator
transition (MIT) and of chalcogenides (GeTe, Ge2Sb2Te5…)
phase change materials (PCM)- showing a non-volatile,
reversible structural and electrical state changes, as
agile elements for switching, frequency reconfiguration
and amplitude modulation of devices operating at
millimeter-waves and THz frequencies.

This letter proposes an amplifier antenna that
integrates gain amplification and pattern
reconfigurability. Using two transistors not only
amplifies the antenna gain but also enables pattern
switching among three states. The antenna and the
microstrip-to-slotline transition serve as the input and
output matching networks of the amplifier, respectively,
which reduces the circuit size. This design achieves the
highly efficient integration of the antenna and the
amplifier. Two integrated antenna elements placed on the
same dielectric substrate form a pattern reconfigurable
antenna. Simulation results show that the designed
pattern reconfigurable amplifier antenna operates over
the frequency band 5.8 GHz to 10.3 GHz. The gain varies
from 11.38 dBi to 16.88 dBi. The gain amplification over
a wide operating frequency band and the radiation
patterns in three states demonstrate the feasibility of
the integrated design.

To address the critical need for modular and flexible
integration in reconfigurable RF integrated systems, a
substrate interconnect model based on standard packaging
is designed and validated for the 32 GT/s Universal
Chiplet Interconnect Express (UCIe) standard. In
reconfigurable architectures, the bandwidth consistency
and electromagnetic isolation of the underlying
interconnects are essential for enabling dynamic
functional scheduling. This work establishes a full-link
model incorporating pillars, vias, and traces on an
organic substrate. Frequency response simulations
demonstrate that at the 16 GHz Nyquist frequency,
Voltage Transfer Function (VTF) loss remains above -7.5
dB and crosstalk is suppressed below -26 dB, satisfying
UCIe specifications for standard packages. Furthermore,
system robustness is verified via statistical eye
diagram analysis, achieving an eye width of 0.925 UI at
a low Bit Error Rate (BER). This study validates the
feasibility of utilizing mature standard packaging
processes to build high-performance, cost-effective
communication platforms for reconfigurable RF chiplet
integration.

This paper proposes a sub-THz conductive-bridging
memristive switch implemented on high-resistivity
silicon for reconfigurable RF front-end applications.
Driven by the increasing demand for low-power, compact,
and non-volatile reconfigurable hardware in beyond-5G/6G
systems, the proposed device explores the feasibility of
extending conductive-bridging memristive switching
mechanisms toward the sub-THz frequency range. The
switch is developed based on a parasitic-aware compact
model, in which the ON/OFF-state resistance transition
is jointly considered with the intrinsic shunt
capacitance and series inductance introduced by the
device geometry and interconnect layout. To suppress
high-frequency degradation, the structural design is
optimized to minimize OFF-state capacitive coupling and
parasitic inductive effects while maintaining a compact
footprint compatible with high-density integration on
silicon platforms. Compared with conventional
semiconductor or volatile switching technologies, the
proposed conductive-bridging memristive switch is
expected to offer near-zero static power consumption,
non-volatile state retention, and enhanced scalability
for large-scale reconfigurable front-ends. The proposed
concept provides a promising device-level solution for
future sub-THz switches, switch matrices, and
programmable passive networks in reconfigurable
transceivers and intelligent RF systems.

This paper presents the on-body characterization of a
horseshoe-slot microstrip antenna with an elevated
ground plane fabricated using flexible MXene conductors
and a PDMS substrate. The design incorporates two
previously developed efficiency-enhancement techniques:
radiator optimization to reduce conductor loss and an
elevated ground plane to mitigate dielectric loss. These
methods improve radiation efficiency by approximately
14% without altering the antenna size or bandwidth. In
this work, the optimized antenna is evaluated under
on-body conditions to assess its suitability for
wearable applications. The results show close agreement
between simulation and measurement, with stable
impedance characteristics, preserved broadside radiation
patterns, and minimal gain degradation when placed on
the body. These findings confirm the robustness of the
efficiency-driven design for wearable applications.

The accurate extraction of material properties from
free-space methods is dependent on several assumptions,
including that the sample has parallel, flat surfaces,
and constant thickness, and that the material is
homogeneous. In reality, none of these are satisfied for
standard samples probed with THz due to the usual
non-negligible surface roughness in the range of tens of
microns. This invited talk will give an overview on the
work done at the University of Birmingham to develop
methodologies that pivot around quasi-optical time- and
frequency-domain spectroscopy systems to deal with rough
samples

A branch-independent computational method is proposed,
permitting dielectric material characterization by
extracting its real relative permittivity ɛr from a
propagation factor. The propagation factor, which
describes the interaction between a dielectric and an
electromagnetic wave, is widely employed in material
characterization. However, ɛr extracted from the
propagation factor suffers from phase ambiguity due to
the multi-valued nature of the logarithm operation. The
resulting multiple phase branches correspond to
different ɛr, making it difficult to determine the
correct value. A computational method based on the first
derivative of the phase branch is developed with
closed-form formulas, producing the correct ɛr.
Simulation validation in the 12-18 GHz band is conducted
to demonstrate the method under ideal conditions; an
experimental measurement on PTFE samples follows. Unlike
traditional wideband characterization methods, which
focus solely on a single frequency, the
branch-independent method considers the propagation
factor’s overall behavior in wideband dielectric
material characterization.

This contribution concerns resonator-based
characterization of materials. First, the relevant
physical principles are discussed and illustrated with
EM modeling. Then, industrial round-robin results are
summarized, assessing the commercially available
techniques from the viewpoint of 5G/mmWave applications.
The presentation then focuses on the novel Q-Choked
resonators and their advantages for materials’
characterization in the forthcoming FR3 frequency band.

This paper presents a high-sensitivity microwave probe
for broadband dielectric characterization, achieving
improved accuracy compared to conventional open-ended
coaxial probes based on RG405 coaxial cable. The
proposed design employs a series inductive loading at
the probe tip, implemented using a via-connected
circular patch structure, to enhance electromagnetic
interaction with the material under test. An analytical
circuit model is developed to quantify amplitude and
phase sensitivities, confirming significant improvement
over standard probes. A fabricated prototype
demonstrates superior performance across 1-7 GHz,
validated through measurements of water-ethanol mixtures
with up to 15% water content.

This paper presents a high-sensitivity dielectric
characterization method for thin-film materials using a
ridge gap waveguide resonator. The ridge structure
enhances the electric field interaction with the
material under test (MUT), achieving a 20.5% improvement
in sensitivity. The method requires no vias or metal
plating, offering reusability and broadband operation.
It is verified in Ka-band with RO4350B and in W-band
with quartz film, showing good agreement with
manufacturer data and simulations.

Radiative wireless power transfer (WPT) via microwaves
and millimeter waves is considered a promising
technology to expand the application of electricity. A
lot of historical excellent research and development of
the WPT via microwaves were carried out in 1960s and in
1970s. Recently, advanced WPT business has started in
the world based on the WPT radio wave regulations.
Especially in Japan, new legal WPT radio wave
regulations at 920MHz, at 2.4GHz, and at 5.8GHz was
published in 2022. After the 2022, over 800 WPT base
stations has already installed and are working in
Japanese buildings mainly for battery-free Billing
Energy Management System (BEMS). In Japan in 2026, we
will update the Japanese WPT regulation for more
conveniency. In 2026 in IEEE, discussion for new IEEE
WPT regulation has already started as IEEE Standard
WG3735 originally supported by MTT-S.
Current WPT business is based on the wide beam WPT
technology, in which wireless power is provided widely
to multi-users without beam forming like conventional
wireless communication system. Key technology in the
wide beam WPT is a high efficiency rectenna, rectifying
antenna with diode or CMOS. For the wide beam WPT,
advanced diode or SMOS with high efficiency is required.
In the next step of the WPT, novel beam forming
technology with a phased array antenna is expected. In
this talk, current R&D and business of the WPT via
microwaves and millimeter waves are introduced. The
expectation for the advanced materials for next step WPT
is also explained in this talk.

Oscillator-based sensing offers compact
implementations, with autonomous operation, simple
readout mechanisms, and the possibility of exploiting
nonlinear dynamical phenomena. These phenomena can
significantly enhance sensitivity and provide new
sensing modalities that go beyond conventional
frequency-shift measurements. The central idea is to
deliberately operate oscillators in specific nonlinear
regimes in which measurable quantities-such as
oscillation frequency, locking bandwidth, beat
frequency, spectral structure, or switching
thresholds-exhibit a strong dependence on the properties
of the material under test. The presentation will first
provide an insightful study of how the sensing behavior
of a resonant structure is affected when it is
incorporated into a loop containing an active nonlinear
block. We then address oscillator sensors based on
injection locking, using the boundaries of the locking
band as the sensing observables. We additionally
investigate the high sensitivity of the beat frequency
near the locking edges, which is compared with that of
the original free-running oscillator. In a different
configuration, we synthesize a low-frequency
self-oscillation that, through its coupling to the main
one, enables sensing based on multiple spectral lines.
Using self-injected configurations, we demonstrate
extremely sensitive operation near the hysteresis limit,
as well as the deliberate use of hysteresis to trigger a
state change only when the measurand crosses specific
thresholds. A key aspect is the use of rigorous
nonlinear analysis and design methodologies that combine
analytical modeling, bifurcation theory,
describing-function techniques, and harmonic-balance
simulations, enabling a systematic understanding of the
various dynamical behaviors on which these sensors are
based. Experimental implementations based on transistor
oscillators operating in the microwave range demonstrate
the practical feasibility of these concepts. They
illustrate how nonlinear dynamical phenomena, often
regarded as undesired effects, can instead provide
powerful sensing mechanisms and open new opportunities
for the design of compact, highly sensitive microwave
sensors.

This paper presents a low-loss tunable bandpass filter
(BPF) based on a boundary-reconfigurable patch
resonator. Frequency tuning is realized by reconfiguring
the resonator boundary conditions without using
conventional lumped elements such as varactor diodes,
thereby maintaining low insertion loss. The fabricated
filter demonstrates a center-frequency tuning range from
0.45 to 1.15 GHz, corresponding to a tuning ratio of
2.56. Across the entire CF tuning range, the measured
minimal insertion loss is maintained below 1.35 dB. In
addition, bandwidth reconfigurability is realized, with
the fractional bandwidth adjustable from 20.5% to 32.0%.
Moreover, transmission zeros are generated at both sides
of the passband which enhance the BPF’s selectivity.
Therefore, the proposed filter provides a practical
solution for low-loss tunable filtering applications.

This paper presents a compact tunable bandpass
filter（TBPF）realized using Through-Silicon Via (TSV)
technology. The controlled tunable transmission zeros
(TZs) are introduced to achieve bandwidth tuning. The
area of the filter is 720×510um2. The result
demonstrates a wide continuous bandwidth tuning range
from 10 GHz to 14.92 GHz, with a minimum insertion loss
of 0.113 dB.
Index terms: Tunable, BPF, RF front-end, 3d integration

This paper presents a wideband dual-linear polarization
Ku-Band phased-array meta-antenna that eliminates the
need for an air cavity. By incorporating a metasurface,
the proposed antenna achieves a broad operational
bandwidth from 10.7 GHz to 14.5 GHz with a realized gain
exceeding 1.7 dBi. The wideband performance is realized
without an air cavity, thereby simplifying the
fabrication process. By leveraging this antenna design,
a method for achieving both dual-linear and
dual-circular polarization is demonstrated. Implemented
on a cost-effective PCB platform, the proposed phased
array offers a low-cost solution well-suited for
satellite communication applications.

Multibeam scanning capabilities are essential for
modern wireless communication systems, including 5G/6G
MIMO and satellite technology. This paper presents a
novel approach to implementing a 3-beam feeding network
using a compact planar six-port regular hexagonal hybrid
coupler. Compared to conventional Nolen matrix (NM)
designs that rely on a cascaded arrangement of multiple
couplers and phase shifters, the proposed design
integrates these functionalities into a single planar
component. This approach achieves a significant size
reduction of over 70% while maintaining excellent RF
performance. To verify the concept, a prototype
operating at 2.45 GHz was designed and fabricated. The
measured results demonstrate an equal power division of
5±0.9 dB and phase differences of ±120 deg and ±0 deg
across the 2.28–2.61 GHz band. The simplicity and
effectiveness of this approach make it highly suitable
for compact, scalable beamforming systems.

This paper presents a novel design framework for
3rd-order on-chip bandpass filters (BPFs) based on
short-circuited ring patch (SCRP) resonators fabricated
using through-glass via (TGV) technology on fused silica
substrates. The filter units are implemented using
1/n-mode SCRP resonators. To achieve efficient and
precise structural optimization, a multilayer perceptron
(MLP)-based model is employed, trained on
electromagnetic simulation data to map geometric
parameters to S-parameter responses. The optimized
design, targeting 5G n257/n258 bands, and filter
prototypes were designed, fabricated, and experimentally
characterized. Both filters exhibit excellent
performance, with measured insertion loss (IL) below 1.5
dB and return loss (RL) exceeding 15 dB. The measured
results show strong agreement with simulations,
validating the effectiveness of the proposed
MLP-assisted design methodology.