This work presents a planar circularly polarized (CP) magneto-electric (ME) dipole antenna array with sequential rotation (SQ) feeding, designed for robust mm-wave Internet-of-Vehicles (IoV) applications. In vehicular environments, antenna performance is affected by orientation variations, reflections, and fabrication tolerances, making stable polarization and structural robustness essential. To address these challenges, a planar and fabrication-tolerant architecture is proposed, eliminating multilayer structures, air cavities, and complex geometries. The antenna employs an asymmetric configuration to generate CP while maintaining stable performance under practical variations. Sensitivity analysis confirms consistent impedance matching and axial-ratio performance under typical fabrication tolerances. The single element achieves an impedance bandwidth (IBW) of 38%, axial-ratio bandwidth (ARBW) of 9.35%, and a gain of 5.5 dBic. To enhance gain while preserving robustness, 2×2 arrays using a simplified SQ feeding network are implemented, achieving a measured IBW of 21.56–43.03 GHz (66.5%), ARBW of 22–31 GHz (34%), and a gain of ~12 dBic. The antenna also demonstrates stable performance on a vehicular platform and supports seamless integration with mm-wave front-end systems, making it suitable for V2V, V2I, and V2N IoV applications.

A K-/Ka-band high-power single-pole-double-throw (SPDT) switch featuring absorptive characteristic for mobile satellite communication (SATCOM) phased arrays is presented in this work. Conventionally, the operating bandwidth of the absorptive RF switches were limited due to the adoption of two quarter-wavelength transmission lines for the reflective and absorptive branch. Through theoretical analysis, a wideband absorptive SPDT switch was realized using the 0.12-μm GaN/SiC high-electron mobility transistor (HEMT) technology. The experimental results have demonstrated an insertion loss of less than 3.2 dB, an isolation of greater than 26.2 dB, and an input 0.1-dB compression point (P0.1dB) of better than 32.6 dBm from the 17-30 GHz, respectively.

A highly linear power amplifier (PA) utilizing stacked-FET configuration and harmonic-tuning technique targeting for millimeter-wave applications is presented in this work. Fabricated using standard 150-nm GaN/SiC device technology, a small-signal gain of 23.7 dB, a peak power-added-efficiency (PAE) of 37.7%, and a saturated output power (Psat) of 30.8 dBm was evaluated with continuous-wave (CW) excitation at 38 GHz, respectively. With the characterization using a standard 200 MHz 64-quadrature-amplitude-modulation (QAM) 5G new-ratio (NR) signal, the fabricated PA exhibited an error-vector-magnitude (EVM) of -27.9 dB with an average PAE of 21.4% while delivering an average output power of 25.1 dBm at 38 GHz. The experimental results have evidenced that the design technique is capable of achieving wide harmonic-tuning range for millimeter-wave amplifiers requiring high linearity and enhancement in overall efficiency.

A 4-port MIMO antenna, featuring transparency and flexibility with a low profile of$0.47\lambda \times 0.58\lambda \times 0.010\lambda $(at 3.19 GHz) is proposed. Transparency and flexibility of the antenna are achieved by utilizing materials like PET and silver oxide. The fundamental antenna comprises a semi-hollow circular structure with notches on the upper side and a lower side consisting of a partial ground to attain an ultrawideband response. To enable MIMO capability, four identical elements are strategically positioned in a sequential rotational arrangement, effectively realizing the diversity performance. A centrally positioned circular slotted structure, linked by vertical lines, establishes the ground connection between the elements. By upholding a shared reference, the isolation surpasses 20 dB. The antenna exhibits a peak gain of 2.49 dBi and maintains an efficiency greater than 40%. It also achieves an impressive 10-dB impedance bandwidth (IBW) spanning (97.83%) from 3.19 to 9.30 GHz, while maintaining an envelope correlation coefficient (ECC) of under 0.1. The decent results of S-parameters and ECC assessments under bending conditions, as well as a comprehensive time-domain analysis, all of which underscore its outstanding performance. The UWB flexible transparent MIMO antenna fulfills crucial criteria for IoT applications, offering high data rates, spectrum efficiency, adaptability, and easy integration. This technology holds significant promise for the rapidly growing IoT ecosystem.

Abstract This article proposes an electrically small, probe-fed Ultra-Wideband (UWB) monopole antenna on a slotted truncated ground plane for breast cancer detection. The physical footprint of the proposed antenna element is 33 mm × 35 mm × 0.5 mm. This element is designed on the low-cost FR4 Epoxy substrate with a thickness of 0.5 mm. The proposed antenna has an electrical size of 0.33λ × 0.35λ × 0.005λ at the lowest frequency of operation; the radiator offers an impedance bandwidth of 8.34 GHz, which implies a fractional bandwidth of 115.5%. A compact dual-polarized antenna topology with two orthogonally placed probe-fed monopole antennas is proposed to achieve polarization diversity. The impedance characteristics of the individual radiating elements are maintained in spite of the electrical proximity of the radiators. The numerically computed and experimentally measured results of dual-polarized electrically small UWB antenna agree quite well. The proposed dual-polarized antenna topology is investigated for its utility in breast cancer detection in simulation.