Basem Abdelaziz Abdelmagid

Joint Communication and Sensing (JCAS) platforms are emerging as a foundation of next-generation mmWave (MMW) and sub-THz systems, enabling both high-throughput data transfer and angular localization within a shared signal path. This paper investigates multibeam architectures for JCAS that simultaneously optimize waveform shaping and beamforming across the time, frequency, code, and direct analog/ radio frequency (RF) domains. The paper compares Orthogonal Frequency-Division Multiplexing (OFDM), Frequency Modulated Arrays (FMA), Time-Modulated Arrays (TMA), direct RF/MMW modulation, and Code-Division Multiple Access (CDMA)-based systems with respect to spectral efficiency, beam orthogonality, latency, and Angle-of-Arrival (AoA) estimation accuracy. The results highlight architecture-specific trade-offs among beam agility, efficiency, accuracy and resolution, and complexity. It also provides a framework for selecting JCAS front ends optimized for power, latency, inter-beam and multi-user interference, and rapid system reconfiguration.

This work presents a 120-GHz $4 \times 4$ active reconfigurable reflective relay array that can enable D-band non-line-of-sight (NLOS) wireless communication links in scenarios with heavily blocked line-of-sight (LOS) paths. The relay array employs orthogonally linear-polarized on-chip $4 \times 4$ transmitting/receiving antenna arrays, and is 2-D scalable on a $\lambda $ / $\times \lambda $ /2 grid. In addition, mixed-signal and low-latency loops are integrated within the front ends of the relay’s channels to detect the angle-of-arrival (AoA) of the external incident beam in both 2-D azimuth/elevation planes. These detection loops operate on the fly, at the carrier frequency, without the need of down-conversion, which avoids lossy mixers, complex local-oscillator (LO) distributions, and additional signal delays, ensuring a low-complexity and a high-scalability relay array design. The relay array operation is analyzed in the presence of non-idealities, including the finite isolation between the transmitting/receiving antennas and the channels’ mismatches. The $4 \times 4$ reflective relay array is implemented in GlobalFoundaries 22-nm CMOS fully-depleted silicon-on-insulator (FD-SOI) technology with a total area of $5\times 5$ mm. Each channel achieves a measured average gain of 23.6 dB with a 3-dB bandwidth from 110 to 125 GHz, while offering a 360° reconfigurable phase range with a step of 11.25°. Without any prior knowledge of the AoA of the external incident beam, over-the-air (OTA) measurement results demonstrate successful 120-GHz 1.3-m NLOS wireless links through the relay array achieving 64-QAM 2.4, 4.8, and 6 Gb/s with corresponding EVM_rms of 3.4%, 4.6%, and 5%, respectively.

This work presents a compact 110 to 140 GHz bi-directional D-band passive phase shifter based on combining a 5-stage capacitively-loaded reflective-type phase shifter (RTPS) with a wideband 0∘/180∘ stage. The design achieves a 360∘ phase range with a resolution of 11.25∘. By applying: (1) a wideband RTPS design methodology on the stage level, (2) frequency/switching-staggering techniques among the RTPS stages, and (3) a balun-staggering technique into the 0∘/180∘ stage, the design achieves calibration-free operation with frequency-invariant codes over 24% fractional bandwidth (FBW). The design is implemented in GlobalFoundaries 22-nm CMOS FD-SOI technology with a compact core area of 130 μm × 480 μm. It achieves measured RMS phase and magnitude errors lower than 2.38∘ and 0.63 dB respectively across the entire operating bandwidth using the same frequency-invariant codes.

Fast and safe charging in electric vehicles at low temperatures is a significant challenge for traditional methods that often separate the heating and charging processes. This study presents a strategy to coordinate heating and charging optimization by integrating heating with alternating current and charging with direct current while adhering to battery safety needs. Additionally, a dynamic weighting mechanism is introduced to flexibly adapt to various scenarios, such as prioritizing charging speed or energy efficiency. At -20°C, with a weight coefficient of 0.9, charging from 20% to 80% state of charge takes only 2650 s—four times faster than the current charging after preheating—with an energy consumption of 5597 J. When the weighting coefficient is 0.1, the charging duration extends to 5030 s, while energy consumption drops to 4816 J. The proposed strategy provides a flexible, high-performance solution for charging at low temperatures, greatly enhancing its applicability in real-world scenarios.

This article presents a scalable D-band active reflective relay array that can enable nonline-of-sight (NLOS) wireless communication links with multibeam reception and broadcasting capabilities, targeting 6G distributed MIMO (D-MIMO) applications. By adopting two time-modulated linear periodically time-varying (LPTV) arrays at the receiving and transmitting frontends of the relay, the proposed relay concurrently receives/transmits multiple beams with multiple independent data streams from and to multiple spatially distinct wireless nodes. The local oscillator (LO)-less scheme of the proposed relay further obviates the losses and power consumption of mixers and LO distribution, ensuring a low-cost, low-complexity, and scalable relay array design. As a proof of concept, a D-band 120-GHz relay array prototype with eight-element transmitter (TX) array and eight-element receiver (RX) array is implemented in GlobalFoundaries (GF) 22 nm complementary metal-oxide–semiconductor (CMOS) FD-SOI technology. The prototype relay implementation is fully integrated with on-chip orthogonally-polarized RX/TX antenna arrays. By postprocessing the fabricated chips, substrate grooves are created at the back side of the chips to partially suppress the substrate modes and enhance the isolation between the RX and TX antenna arrays. Over-the-air (OTA) measurement results demonstrate successful 120-GHz 16-QAM 1 and 2 Gbps per beam NLOS wireless links through the relay with an EVM_rms of 6.4% and 8.9%, respectively, in the case of one external transmitting node communicating through the relay with up to six receiving nodes. The measurements also demonstrate an EVM_rms of 9.5% and 12.2%, respectively, in the case of two external transmitting nodes communicating through the relay with up to five receiving nodes.

This work presents a $D$ -band multi-input multi-output (MIMO) transmitter (TX) array with a four-element joint static/dynamic beamformer. The proposed beamformer combines a static beamformer and a space-time modulated dynamic array to produce a large number of concurrent beams with fewer array elements and multiple independent data streams, essentially achieving RF-domain beam number multiplication. Consequently, the beamforming system only requires low-overhead RF/analog chains and simple digital computation, making it conducive to low-cost applications. More importantly, the concurrent multiple beams are formed at distinct carrier frequencies at various spatial angles. This allows easy discrimination of adjacent beams, which is essential for MIMO communication for high link throughput as well as MIMO radar operations for rapid situational awareness sensing of surroundings and one-shot localization. Traditional $N$ -element analog beamforming arrays require an $M$ set of independent beamformers to generate $M$ independent beams. The proposed $N$ -element beamformers can generate up to $M\times (N+1)$ concurrent beams by cascading $M$ -beam beamformers with $N+1$ time-modulated array (TMA) operation, which offers a new operation freedom to trade off among number of concurrent beams, array gain, spectral efficiency, and beam angle dependency. As a proof of concept, a $D$ -band 125-GHz four-element TX array is implemented in a GlobalFoundaries 22-nm CMOS FD-SOI process with a flip-chip package. With the beam-multiplication effect, the four-element TX array radiates a total of concurrent 20 beams with a unique space-to-frequency mapping over $\pm$ 60 $^{\circ}$ total beam field-of-view (FoV). Through over-the-air measurement, the TX array demonstrates concurrent four beams with 4-Gb/s 16-QAM modulation and reconfigurable space-to-frequency mapped 20 beams, each with 100-MHz bandwidth frequency-modulated continuous-wave (FMCW) chirping to support joint MIMO communication and sensing.

This letter presents a novel 3-dB transformer-based quadrature coupler (TFQC) that is based on lumped inductors connected between the coupler ports. Compared to previously reported 3-dB TFQCs that strictly require a coupling coefficient ( $k$ ) of 0.707, the proposed coupler can be designed with any arbitrary $k$ for the transformer (TF), offering a much-expanded design space and scalability across frequency and different technologies. In addition, the required TF’s inductance of the proposed coupler is reduced compared to previous TFQC designs, allowing for a further size reduction. To validate the theory of the proposed coupler, a 48–63 GHz prototype is implemented in a 22-nm CMOS FDSOI technology, occupying an area of 0.017 mm $^2$ with an average insertion loss (IL) of 1.81 dB.