Compact Shared Aperture Metasurface With Power Splitting for Simultaneous Wireless Information and Power Transfer

Simultaneous wireless information and power transfer (SWIPT) with a power-splitting (PS) scheme has been extensively studied for Internet of Things (IoT) applications. However, the PS scheme usually employs a power divider or hybrid coupler for splitting the radio frequency (RF) signal, which makes the receiver structure complex and introduces extra losses. To address this challenge, we propose a novel PS scheme for SWIPT using a shared aperture metasurface (SAM). The SAM includes a rectifying metasurface on the first substrate layer and a communication metasurface antenna (meta-antenna) on the second one. The rectifying metasurface can harvest most RF signals as energy and transmit a small portion for communication, whose ratio can be adjusted by the etched gap width between two substrate layers. A prototype with 8.5:1 ratio of energy to information is designed and fabricated. The measured results show that the rectifying metasurface has a RF to direct current (DC) conversion efficiency over 50% at any polarization direction within a wide reception range of 45° oblique incidence. A maximum data rate of 350 Mb/s for 128-QAM is measured when bit error rate (BER) is lower than $10^{-6}$ and signal-to-noise ratio (SNR) is lower than −30 dB. An SWIPT system demonstration employing the proposed SAM for environmental monitoring sensor nodes is presented. When sensors receive the RF signal from the transmitter, they can convert it to DC power for self-powering and send the environmental data back to the transmitter.