A Dual-Band Dual-Mode Wearable Antenna with Different Beam Directions for Off-Body Communications in Emergency Rescue Scenarios

This work presents a dual-band dual-mode textile wearable antenna with different beam directions for off-body communications in emergency rescue scenarios. The hybrid architecture combines a quasi-Yagi structure with a patch element, excited by a shared microstrip feeding line. This integrated design achieves dual-band operation with corresponding dual-beam spatial coverage patterns optimized for horizontal plane and elevated hemisphere radiation when deployed on human body. A hand-made prototype demonstrates stable on-body performance with -10 dB impedance bandwidths of 14.3% (2.21-2.55 GHz) and 15.5% (3.27-3.82 GHz). Experimental validation confirms gains exceeding 5.5 and 3.7 dBi in free space and 3.5 and 3.8 dBi in on-body deployment. The measured results achieved satisfactory agreement with numerical simulations, validating the practical applicability of this design in body-worn emergency communication scenarios.