A Design of Dual-Band Dual-Layer Shoulder Pad Antenna for WBAN Communications

A novel dual-layer shoulder pad antenna is designed for Wireless Body Area Network (WBAN) communications. The proposed antenna design incorporates a half-mode substrate integrated waveguide (HMSIW) cavity backed non-resonant slot for 5 GHz operation band and a ring structure positioned above the cavity for 2.45 GHz. The antenna's bandwidths are about 5.7% in the 2.45 GHz band and 22.1% in the 5 GHz band. In the lower band, the antenna exhibits quasi omni-directional radiation characteristics, while in the higher band a high gain of 6.927 dBi is achieved for high data rate communication. The high free-space efficiency of 84.8% and 55.0% on-body efficiency at 2.45 GHz, along with 95.5% free-space efficiency and 73.1% on-body efficiency at 5.4 GHz embody the antenna to meet the requirements of WBAN communication. Furthermore, simulation on human body (with 0.5 W input power) indicates specific absorption rate (SAR) of 1.32 W/kg at 2.45 GHz, 0.84 W/kg at 5.40 GHz and 0.88 W/kg at 5.95 GHz, confirming compliance with safety regulations.