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 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(VOUT-DC)</tex> as well as power conversion efficiency (PCE). The proposed rectifier is designed to operate at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$f=1.8$</tex> GHz which shows a maximum PCE of 62% for an RF input power <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(PIN)</tex> level of 8 dBm and optimum load <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(RL)</tex> of 820 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ω</tex> . A DC-DC boost converter and an energy storage capacitor <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(COUT=370μ F)</tex> 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 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">PIN</tex> levels. The developed rectifier can be used in RF energy harvesting and wireless power transmission systems to power sensor nodes and IoT devices.