A High-Efficiency, Simple-Structure, Compact Wideband Microwave Energy Harvester for Wirelessly Powered IoT Receivers

Abstract

Wireless data links and wireless power transfer (WPT) have become emerging topics in IoT applications. A simple-structure high-efficiency rectenna is the key technology for wirelessly powered IoT receivers. Herein, we explore a unified co-design technique that synergizes wideband circular polarization (CP) antennas with high-frequency Gallium Arsenide (GaAs) Schottky diodes across the 10–20-GHz range. Our approach involves a systematic study of the rectifier’s nonlinear behavior over wide frequency ranges, followed by the identification of an effective antenna candidate for co-design. This strategy effectively obviates the need for matching networks, filters, and extra components typically found in conventional wideband rectennas. Consequently, we present a co-design example: the proposed CP antenna, featuring a measured impedance bandwidth of 11.65–16.9 GHz (36.8%), a 3-dB axial ratio bandwidth (ARBW) of 12.55–16.9 GHz (29.54%), and a measured peak gain of 8.5 dBic. This design integrates CP magneto-electric (ME)-dipole units with rectifier topologies. Measured results show an RF-DC efficiency of over 50% within the 11–14.6 GHz (28%) and 10–18 dBm power range, with a maximum conversion efficiency of 61%. This design approach holds broad applicability for all wideband rectennas, offering notable advantages in terms of simplicity, efficiency, and compactness.