An On-Body Flexible Wireless Energy Harvesting Metasurface Operating in 5.8 GHz Band

An on-body flexible energy harvesting system oper-ating in the 5.8 GHz ISM band is proposed, which is comprised of an energy harvesting metasurface (EHM) and three rectifiers. The proposed EHM is composed of $3\times 3$ unit cells cascaded into three columns, and a direct-current (DC) domain combination is adopted to collect the energy harvested by the three columns of unit cells by using three rectifiers. A flexible substrate is used for implementation of both the EHM and rectifiers to achieve flexibil-ity. The simulation results show that the proposed EHM achieves an energy harvesting efficiency of 82.8% for the EHM in plane form and $> 60\%$ in bending form with a bending radius $> 40$ mm, demonstrating good on-body robustness. The designed rectifier achieves a rectification efficiency of 33.4 % with 1 V voltage output under 0 dBm input. The proposed EHM has a small size of 66 ${}^{*}66^{*}1.22 \text{mm}^{3}$, suitable for daily wearing on the chest or back by humans for house care or hospital monitoring applications.