Due to its favorable balance between coverage and bandwidth availability, the upper mid-band frequency range (7 to 24 GHz) is expected to play a key role in sixth-generation (6G) networks. This paper presents an independently controllable dual-polarized reconfigurable intelligent surface (DP-RIS) operating in one of the candidate upper mid-band segments for 6G, namely 14.8 to 15.35 GHz. The proposed unit cell is based on the diagonal placement of mutually orthogonal tunable radiators loaded with varactor diodes, combined with static dual-polarized radiators. Full-wave electromagnetic simulations demonstrate up to 60 dB cross-polarization isolation (XPI) within the operating band. A simulation technique that significantly accelerates the unit-cell analysis and design process is also introduced. For experimental validation, a 16 × 16 DP-RIS prototype is fabricated and characterized. The measured results show good agreement with simulations. A continuous reflection-phase range of approximately 297° is achieved. By applying independently controlled reverse-bias voltages to the varactor diodes through a dedicated control board, the reflected beam can scan up to ±60°. Owing to its high polarization isolation and dual-polarized operation, the proposed DP-RIS is well-suited for full-duplex, integrated sensing and communication, and RIS-assisted wireless communication systems.

This paper presents angle-resolved radio channel measurements at 3.9 GHz and 28 GHz conducted in a densely packed industrial production hall. The channel was captured at 87 positions with 3D distances ranging from 13 m to 87 m. The power, delay, and angular characteristics are evaluated and compared with the 3GPP TR 38.901 Indoor Factory model. Frequency-dependent models for path loss, $K$-factor, RMS delay spread, and azimuth spread of arrival are extracted and crosscorrelations between the parameters are analysed. The results show that the $K$-factor and delay spread are nearly frequency independent, while the angle spread increases with frequency.

This paper presents the sensing capabilities of an integrated communication and sensing (ICAS) capable cylindrical phased array (CPA) prototype and proposes a super-resolution azimuth angle of arrival (AAoA) estimation algorithm to perform accurate sensing and localization. The CPA operates at 26.5 GHz, supports full 360° azimuth coverage by electronic beamforming with 48 overlapping beams and a directivity of 18 dBi. To verify the sensing capabilities of the CPA, controlled experiments are conducted both in an anechoic environment with corner reflectors and an indoor open office. Then, to enable comparison, the experiments in the anechoic environment are repeated using an established setup that employs a uniform circular array and a variant of MUSIC for AAoA estimation. The experiments demonstrate time-of-flight/ranging estimation accuracy on the order of 0.1 ns and localization accuracy on the order of 1° for both arrays. Thus, the CPA prototype can perform monostatic 6G ICAS in real-world.

This study presents the development of a 3D-printed, wideband, dual-polarized magneto-electric dipole antenna. The proposed antenna demonstrates exceptional cross-polarization isolation (XPI) between its two mutually orthogonal RF ports, achieved through innovative feeding probes, specifically an inverted Gamma-shape and a conventional Gamma-shape probe. The analysis reveals that misalignment between probes can impair XPI; this phenomenon is systematically examined through electromagnetic full-wave simulations. A practical remedy is provided using four plastic rods strategically positioned through the probes and posts. Measurements indicate that XPI exceeds 50 dB across the common operating frequency range of 3.05-4.13 GHz (30%). The maximum realized gain is approximately 7.9 dBi, with a nearly flat response and stable radiation patterns across both ports throughout the bandwidth. The proposed antenna offers a cost-effective, 3D-printed design, wideband radiation performance, and exceptional port-to-port isolation, demonstrating significant potential for full-duplex wireless communication and ICAS applications.

This paper presents a novel, independently controllable dual-polarized reconfigurable intelligent surface (RIS) unit cell for 6G upper mid-band ( 7.125 $7.125$ 7.125 - 24.25 GHz $24.25\,\mathrm{GHz}$ 24.25 G H z ) applications. The proposed unit cell is based on the diagonal placement of mutually orthogonal tunable radiators (loaded with varactor diodes) alongside static dual-polarized radiators. Full-wave electromagnetic simulations of the unit cell demonstrate a phase shift range of 270 ring $270<^>{\circ}$ 270 degrees , a maximum reflection loss of 4.5 dB $4.5\,\mathrm{dB}$ 4.5 d B , and 61 dB $61\,\mathrm{dB}$ 61 d B cross-polarization isolation (XPI) within a 400 MHz $400\,\mathrm{MHz}$ 400 M H z frequency range centered at 15 GHz $15\,\mathrm{GHz}$ 15 G H z . Furthermore, full-wave simulations of a 16 times 16 $16 imes 16$ 16 & times; 16 RIS panel were conducted for various reflection angles under both TE- and TM-polarized illuminations. The results demonstrate a wide-angle beam-steering capability of plus or minus 60 ring $\pm60<^>\circ$ +/- 60 degrees , with a maximum beam-pointing error of only 1.7 ring $1.7<^>{\circ}$ 1.7 degrees . The proposed RIS also exhibits accurate and stable reflection control under wide-angle excitation. A 3 times 3 $3 imes 3$ 3 & times; 3 prototype was fabricated to validate the unit cell's performance. Measurement results agree with the simulations, yielding a 270 ring $270<^>{\circ}$ 270 degrees phase shift, approximately 7 dB $7\,\mathrm{dB}$ 7 d B reflection loss, and 24 dB $24\,\mathrm{dB}$ 24 d B XPI. The proposed RIS is a promising candidate for future 6G communication systems.

This paper presents metrics and measurement methods for the experimental characterization of helicopter rotor blade modulation of the wireless propagation channel. Broadband bistatic channel measurements were conducted at three widely separated carrier frequencies (302 MHz in the UHF band, 4.9 GHz in the C-band, and 27.1 GHz in the Ka-band) for three military helicopters (CH-53, Tiger, and UMAT) at the Bundeswehr Technical and Airworthiness Center for Aircraft in Manching, Germany. The time-variant channel was analyzed in terms of the Doppler Power Spectrum and the RMS Doppler spread, the Doppler spectrogram, and the Power Time Profile. The RMS Doppler spread values were found to be moderate (up to 106 Hz), which is attributable to the predominantly lateral blade motion relative to the line-of-sight path. The Power Time Profiles revealed periodic blockage attenuations of up to 15 dB at Ka-band, increasing significantly with the carrier frequency; at 302 MHz, the blockage attenuation does not exceed 2.3 dB and the RMS Doppler spread stays below 10 Hz. The measured blockage attenuation was modeled using the double knife-edge diffraction model, showing good agreement with the measurements. The distinct micro-Doppler signatures visible in the spectrograms are identified as a potential resource for helicopter classification and passive radar applications.

This paper presents the Geometrical Optics (GO) and Physical Optics (PO) techniques for calculating the radiation pattern of a dielectric lens mounted on top of an open-ended WR6 waveguide. A ray tracing tool is used, and the far-field radiation pattern is calculated by applying Kirchhoff's Diffraction Theory on the lens surface. The results from the asymptotic methods are compared with full-wave simulation and far-field measurements at 160 GHz, with good agreement of the main lobe.

This paper presents results of a channel measurement campaign carried out in a production hall of Rohde & Schwarz in Memmingen, Germany. The channel measurements were performed with a novel time-domain correlative channel sounder operating in the D-Band at a carrier frequency of 160 GHz. The channel measurements were performed and an-alyzed with respect to the topic of beam-steering and macro-diversity gains. It was found out that an average macro-diversity gain of 3.2 dB for line-of-sight and 5.7 dB for non-line-of-sight is achieved.

This paper presents the design and implementation of novel dual-channel (MIMO hybrid) beamforming wireless front-ends operating in the D-band (sub-THz range), optimized within the 150 to 170 GHz frequency spectrum. The development incorporates analog beamforming networks realized through two 16x16 microstrip Rotman microwave lenses and dual sets of 1to-16 RF MMIC switches, in conjunction with a 16x2 antenna array comprised of low-profile on-silicon patch antenna elements and a PTFE elliptically extruded dielectric lens. The resulting architecture produces 32 distinct RF beams bifurcated into two sets of 16 beams, each oriented at two elevation angles. Each set is characterized by beams spaced 4 degrees apart in azimuth, collectively resulting in a 64-degree azimuthal scanning capability. Furthermore, the transmit front end is outfitted with 32 parallelized power amplifiers distributed across 8 InGaAs MMIC chips, equipping it to yield approximately 50 dBm effective isotropic radiated power (EIRP). In parallel, the receive front end comprises 32 low-noise amplifiers (LNAs) similarly arrayed across 8 InGaAs MMIC chips, each delivering an active gain exceeding 30 dB, which augments the overall passive antenna array gain of 25 dBi.

This paper presents two units of Y-band (325-500 GHz) and two units of D-band (110-170 GHz) all-pole inline Chebyshev band-pass filters (BPFs) using high-precision computer numerically controlled milling. The filters are based on six-coupled resonant cavities and are designed for a 20 dB return loss in a 10 GHz bandwidth centered around 470 GHz and 160 GHz with two taper sections at the input and output. Statistical analyses of the design parameters are performed to estimate the manufacturing tolerance. Microscope measurements are done and it is seen that machine tolerance on cavity lengths of about 3.5 microns causes a 2 GHz center frequency shift in Y-band. Measurements validate the analyses. The fabrication repeatability in the D-band is more consistent than in the Y-band. Indeed, two Y-band BPF units have a center frequency shift difference of 6 GHz while the the D-band BPF units have almost identical responses.

In this paper, we introduce a novel time domain correlation based channel sounder that operates at 485 GHz. The channel sounder targets the Y-band ($330 \text{GHz}-500 \text{GHz}$) and covers a center frequency up to 500 GHz. The setup has been validated in the laboratory for conducted and over-the-air measurements. The conducted measurements report a dynamic range of around 80 dB without spurious peaks, and a linear behavior between added attenuation and dynamic range with constant relative noise floor. The over-the-air measurements report a match of the line-of-sight path's propagation length and normalized received power.

This paper presents a D-band (150-170 GHz) $16 \times 2$ planar patch antenna array, integrated with a dielectric lens, designed to facilitate dual-beam (hybrid) beamforming capabilities. The configuration employs both the array factor and the lens to achieve beam collimation across distinct focal planes. The patch antenna array elements are designed based on a band-pass filter topology on high-resistive silicon substrate, and optimized for the PTFE dielectric lens material situated atop the array. The extruded elliptical dielectric lens with the patch antenna array reported in EM simulation a gain of 26.8 dBi and scan angle of +/−30° at 150 GHz. Furthermore, an asymptotic analysis method has been employed to investigate the variations in beam tilt relative to the size of the dielectric lens.

This paper proposes a novel independently controllable dual-polarized 2-bit unit cell with excellent cross-polarization isolation (XPI) for reconfigurable intelligent surface (RIS) applications with $\mathbf{4 0 0} \text{MHz}$ bandwidth centered around 15 GHz. The proposed RIS unit cell is based on orthogonally placed slotted bowtie elements loaded with varactor diodes, square rings to increase phase shift range, and dummy square patches to minimize the reflection loss. The full-wave electromagnetic simulation results of the unit cell demonstrate the reflection phase shift up to 270 degrees, a maximum reflection loss of 4.1 dB, and 55 dB of XPI within the operating bandwidth. Furthermore, $16 \times 16$ element panel simulations of the RIS have been performed for different reflection angles under TE and TM-polarized illuminations. The results indicate a wide-angle scanning range within -60 to +60 degrees with a maximum of 1.7 degrees of beam pointing error. The proposed RIS also demonstrates precise control under wide-angle excitation.

This paper demonstrates the remarkable flexibility, ultra-broadband capabilities, and high dynamic range of state-of-the-art photonic terahertz (THz) systems for high-frequency measurement and test applications in the (sub-)THz range. We present transmission measurements conducted on two hollow core waveguide filters operating in the D- and Y-bands. Coupling into the waveguide is accomplished through quasi-optical free-space to waveguide coupling. Both filters are characterized using the same photonic system, achieving dynamic ranges exceeding 80 dB in the D-band and 75 dB in the Y-band. These performance levels are primarily limited by cross-talk rather than the system's inherent capabilities.

In this paper, we present an architecture for neuromorphic device-edge co-inference, with application to radio sensing for environment mapping in networked robotics scenarios. The developed demonstration setup integrates a radar sensor, radar preprocessing unit and neuromorphic processing unit (NPU) implemented on-device, while the sensing task (object detection, tracking and environment mapping) is completed at the edge server (access point).

This paper evaluates the performance of a WR6.5 rotary joint utilizing two 3D-printed TE01 mode transducers. The rotary joint, fabricated from AL6061 alloy, was tested in a measurement setup using a vector network analyzer across a frequency range from 140 to 170 GHz. The findings indicate that the rotary joint demonstrates an average insertion loss of approximately -2 dB over a usable bandwidth of 15.85 GHz ranging from 145.25 to 161.1 GHz with phase angle variation of less than 15.3° over a full rotation. The results highlight the viability of 3D printing for creating waveguide structures while also acknowledging limitations in surface finish and dimensional accuracy.

This study investigates the application of adaptive beamforming techniques within D-band sub-terahertz (sub-THz) communication systems tailored for 6G applications. We present a hardware-in-the-loop transmission system utilizing newly developed prototypes of transmit and receive front ends operating in the frequency range from 150 to 170 GHz. The front ends' analog beamforming architecture enables the generation of eight distinct beams with 6 degrees separation in azimuth, thus creating a field of view with 48 degrees one dimensional angular scanning range on either side of the link. The system implements dynamic beamforming based on the 5G New Radio (NR) waveform's design principles for the initial access/beam acquisition procedure. Experimental performance assessments conducted in an indoor environment prove the system's potential to support mobility and mitigate the effects of signal blockage. Specifically, when encountering a line-of-sight link blockage event, the system successfully transitioned to a reflected propagation path, incurring approximately 4 dB of loss. Additionally, a mobile receiver could be tracked while maintaining a 1 dB variation in the wireless link budget. These results demonstrate the feasibility of D-band adaptive beamforming.

The paper showcases a real-time demonstration of an ultra-broadband (4 GHz) integrated sensing and communications (ISAC) operating in the upper D-band at 160 GHz. The demonstration illustrates quasi-monostatic sensing by measuring and estimating delay-Doppler maps, while also maintaining a 4.9 Gbit/s communication link to a remote receiver located 4 meters away, utilizing a single carrier quadrature amplitude modulation (16-QAM) signal. The results of the demonstration indicate that the D-band is suitable for ISAC applications in future mobile communications, especially in the context of 6 G technologies.

This paper presents channel measurements and modeling at 28 and 160 GHz in an industrial-style open office environment with angular information at the receiver. Channel impulse response snapshots are captured at 135 measurement positions for both frequencies and are evaluated in terms of power metrics, delay, and angular characteristics. Frequencydependent models for path loss, delay, and angular spread of arrival and K-factor are estimated, and large-scale parameter cross-correlations are evaluated. The results show that delay and angle spread are not frequency dependent in this environment although twice as many multi-path components were identified at 28 GHz compared to 160 GHz.

This paper presents the design and implementation of an agile sub-terahertz (sub-THz) broadband time-domain photonic channel sounder, capable of characterizing wireless propagation channels within the 100 GHz to 500 GHz frequency range. The sounder employs a hybrid architecture that combines photonic carrier generation through heterodyne mixing of continuous-wave lasers locked to a frequency comb, along with electronic components for broadband sounding sequence synthesis and digitization. This design enables precise and tunable carrier frequency generation, overcoming the limitations of traditional electronic-only systems. Experimental evaluations highlight the system's high temporal resolution, phase stability, and broadband performance, including over-the-air calibration and monostatic channel measurements across three sub-THz bands (160 GHz, 300 GHz, and 450 GHz). The results establish the feasibility of the time-domain photonic channel sounder as a powerful and versatile tool for measuring various, widely scattered, and spread sub-THz bands.