A 915-MHz RF-EH with Varactor-Based Adaptive Impedance Matching for ULV Batteryless Devices

Abstract

Harvesting energy from RF signals is a relevant strategy to power ultra-low voltage (ULV) devices. This article presents an RF-EH system with a varactor-based adaptive impedance matching approach to improve the energy conversion from RF-EH to devices without battery. The proposed circuit was designed on a 65-nm CMOS process and is able to generate a stable supply voltage of 0.4 V from a frequency of 915 MHz while reaching a sensitivity of −18.7 dBm and power conversion efficiency of 58.5% in the target operation.