A Compact RF Energy Harvesting System With an Improved Impedance Matching Network

Abstract

This paper presents a compact RF energy harvesting (RFEH) system with an improved impedance matching network. The antenna includes a matching network consisting of periodic stubs, making it possible not only to adjust S11 when it changed due to fabrication errors but also to design the antenna to be more compact. We initially analyzed the effects of the fabrication errors and variations of S11 with respect to an adjustment of the matching network using an EM simulation. The antenna dimensions overall are 14.5×18.5 mm2 , and it is integrated with an RFEH circuit consisting of a rectifier and power management unit (PMU), which compose the RFEH system. The proposed system was implemented, charging a load capacitor at the received power of -15 dBm and -5 dBm; therefore, the proposed system with the impedance matching network contributes to compactness and can be utilized as the power source for compact Internet of Things (IoT) sensors.