Codesign of Differential-Drive CMOS Rectifier and Inductively Coupled Antenna for RF Harvesting

An effective codesign approach for harvesting systems is described in this article, which is based on a CMOS differential-drive rectifier and an inductively coupled loop (ICL) antenna. The proposed approach acts on both the rectifier and the antenna and aims at optimizing the system performance in terms of efficiency and input sensitivity for a given load specification. Moreover, a rectifier solution is also proposed to enhance the circuit performance by properly driving the transistor bulks without additional components. An RF harvesting system operating at 868 MHz was implemented, which is made up of an ICL antenna on FR-4 substrate and a rectifier fabricated in the 0.13-μm CMOS technology. Measurements in the anechoic chamber show an overall efficiency performance of 34% with an RF input power as low as -21.5 dBm while considering 2.4 V and 1 μA as load specifications.