A Dual-Mode Multi-Polarization Millimeter Wave Wearable Antenna for WBAN Applications

A dual-mode multi-polarization millimeter wave wearable antenna working at 28GHz for wireless body area network (WBAN) applications is presented. Series feed antenna array is proposed to achieve high gain. Feeding network is elaborately designed in order to satisfy the radiation pattern and polarization requirements of on-body mode and off-body mode in WBAN. Series feed antenna array and feeding network are then integrated together to form the dual-mode multi-polarization wearable antenna. The wearable antenna can operate at on-body mode and off-body mode by exciting different ports. When the wearable antenna operates at on-body mode, it has omni-directional radiation pattern with vertical polarization (VP). Additionally, broadside radiation pattern with left hand circularly polarization (LHCP) and right hand circularly polarization (RHCP) can be generated when it works at off-body mode. Simulated bandwidth is 2.68GHz with reflection coefficients lower than -10dB. Additionally, bandwidth of axial ratio lower than 3dB exceeds 4GHz. Maximum simulation gain of on-body mode and off-body mode is 2.1dBi and 5.3dBic, respectively.