Dual-Polarized Wearable Antenna/Rectenna for Full-Duplex and MIMO Simultaneous Wireless Information and Power Transfer (SWIPT)

Owing to the mobility of a wearable antenna and the unpredictable body-centric communications environment, dual-polarization antennas are essential for both communications and energy harvesting. This paper presents a dual-polarized four-port textile antenna/rectenna for wearable simultaneous wireless information and power transfer (SWIPT) applications. The proposed antenna utilizes dual ports for both off-body communication and energy harvesting from horizontal and vertical polarizations. The antenna maintains a 100 MHz bandwidth with an S11 under -10 dB around 2.4 GHz in the presence and absence of the human body, and at least 10~dB small-signal and large-signal isolation between all ports. The antenna maintains a 70-88% measured total efficiency and 8.4--9.6 dBi gain for various on-phantom positions across both communication ports. The measured mutual coupling is under -10 dB between co-polarized rectenna/antenna ports, and under -16~dB between orthogonally-polarized ports. A high RF to DC peak power conversion efficiency of over 70% (+-5%) is achieved with a broadside harvesting pattern. Based on the proposed antenna's performance, SWIPT microstrip antennas can be adopted for both full-duplex and MIMO applications, significantly reducing the complexity of future battery-free networks for both wearable and non-wearable applications.