Design of high-efficiency circularly polarized wideband energy harvesting rectenna using characteristic mode analysis

This paper presents a compact wideband rectifier system for wireless energy harvesting. The presented rectifier system is completed in two stages. In the first stage, a crescent-shaped wideband circularly polarized antenna (CPA) is designed to receive and transmit RF signals using characteristic mode analysis (CMA). And the CPA consists of a monopole antenna at the top and a slot antenna at the bottom, which control the higher and lower operating bands, respectively. In the second stage, a wideband rectifier is designed using a HSMS-2860 Schottky diode and a three-stage matching network. The HSMS-2860 Schottky diodes improve rectification efficiency at medium-power density, and the three-stage matching network effectively increase the operating bandwidth, filter out the output RF signal, and cancel out and stabilizes the impedance. To validate the proposed rectifier system, a crescent-shaped CP receiving antenna and a rectifier operating in C-band are fabricated, and the rectification performance is measured. The measurement results indicate that the proposed rectifier system harvests RF signals on the broadside and backside of the CPA over a wide input power range (8-13 dBm input power).