A triple-mode reconfigurable wearable repeater antenna for WBAN applications

A reconfigurable wearable repeater antenna (RWRA) for wireless body area network (WBAN) applications is proposed. The RWRA can work at triple-mode by controlling the state of PIN diodes, which are repeater, on-body and off-body modes. The antenna is fed by a single port at side instead of bottom for the sake of reducing the profile and improving the coupling strength between the RWRA and an implantable antenna. The total size of the antenna is x28(2)x4.8 mm(3). To validate the performance, the RWRA is fabricated and measured on minced pork. Measured bandwidths at repeater and on-/off-body modes are 5.8, 84, and 54MHz, respectively. Radiation patterns are omnidirectional with vertical polarization at on-body mode and broadside at off-body mode, which measured peak gains are 1.2 and 5.4dBi, respectively. Specific absorption rate (SAR) values at all three modes are analyzed in this article as well. Coupling strength between the RWRA and an implantable antenna is also measured. Besides, the effect of distance and misalignment between them are analyzed.