A Wideband Electromagnetic Energy Harvester Design for Internet of Things (IoT) applications

In this paper, we propose a wide-band microwave energy harvester that uses concentric split-ring resonators. Numerically simulated using CST and COMSOL Multiphysics, the numerical simulation results are presented here, where wide-band electromagnetic energy harvesting (considering 50% efficiency threshold) is achieved, covering the frequency band from 3 GHz to 5 GHz and beyond. The proposed unit cell consists of a metallic ring with two slits in opposite sides, which resonates well at around 3.7 GHz with its reflection coefficient of −23 dB and peak efficiency reaching 99.3%. The structure will find useful applications in the recharging of ultra-low-power devices, including the Internet of Things sensors.