A Compact Microwave Rectifier for Wireless Power Transfer and Energy Harvesting Applications

This paper presents a microwave rectifier with compact size and high efficiency for radio frequency (RF) energy harvesting and low-power internet of things (IoT) applications. The proposed rectifier consists of a matching network, a doubler rectifier, a lowpass (LPF) structure and a low-power electronic circuit. An LPF structure is employed to pass a direct current (DC) rectified signal and to control harmonics which increases the output voltage (V OUT-DC) as well as power conversion efficiency (PCE). The proposed rectifier is designed to operate at f = 1.8 GHz which shows a maximum PCE of 62% for an RF input power (PIN) level of 8 dBm and optimum load (RL) of 820 Ω. A DC-DC boost converter and an energy storage capacitor (COUT = 370 µF) are employed to deliver sufficient DC voltage to power a low-power electronic circuit. The proposed rectifier is demonstrated to be capable of powering a low-power circuit at varying PIN levels. The developed rectifier can be used in RF energy harvesting and wireless power transmission systems to power sensor nodes and IoT devices.