A flexible 2.45 GHz rectenna using electrically small loop antenna

We present the concept and design of a compact flexible electromagnetic energy-harvesting system using electrically small loop antenna. In order to make the integration of the system with other devices simpler, it is designed as an integrated system in such a way that the collector element and the rectifier circuit are mounted on the same side of the substrate. The rectenna is designed and fabricated on flexible substrate, and its performance is verified through measurement for both flat and curved configurations. The DC output power and the efficiency are investigated with respect to power density and frequency. It is observed through measurements that the proposed system can achieve 72% conversion efficiency for low input power level, −11 dBm (corresponding power density 0.2 W/m
²
), while at the same time occupying a smaller footprint area compared to the existing work.