A Broadband High-Performance Wearable Antenna for Next-Generation Radar-Based Imaging

A high-performance wearable antenna array for next-generation radar imaging and electronic travel aid (ETA) systems is presented, addressing a gap not covered by existing millimeter-wave antenna solutions. The proposed design provides robust performance across the majority of the 22 GHz–26 GHz band while meeting stringent requirements for detection at 24.05 GHz–24.25 GHz, such as approximately 30∘–40∘ beamwidth, gain sufficient to enable short–medium-range detection, and a high radiation efficiency and front-to-back ratio (FTBR). Toward this aim, a two-element dielectric resonator antenna (DRA) array is engineered. To isolate the antenna from the user (or the radar mechanical assembly), an artificial magnetic conductor (AMC) optimized for the target frequency band is integrated beneath the array, simultaneously enhancing its performance. Moreover, a tailored Y-shaped power divider is engineered to provide balanced power distribution while minimizing insertion losses at the operating frequency. Together, the optimized structures enable the array to meet the stringent performance requirements. The resulting device dimensions are 36.5 × 32.78 × 4.732 mm3 and it provides a wide bandwidth (14.30%), a gain of 8.5 dBi, 93.5% radiation efficiency and a front-to-back ratio (FTBR) close to or exceeding 20 dB across the detection band, in the free space. The experimental characterization of the manufactured prototype, based on the measurement of impedance matching, validates the proposed architecture, confirming its suitability for compact, wearable radar ETA systems. This work represents a significant advancement towards an optimal antenna solution for wearable sensing, filling a gap in the current antenna literature.