A Reconfigurable Hybrid RF Front-End Rectifier for Dynamic PCE Enhancement of Ambient RF Energy Harvesting Systems

This paper presents a reconfigurable hybrid Radio Frequency (RF) rectifier designed to efficiently convert AC RF power to DC voltages for an energy harvesting system. The proposed reconfigurable rectifier adopts the advantage of low conduction loss in the switch-connected rectifier and low reverse current loss in the diode-connection rectifier topology to enhance its power conversion efficiency (PCE). Capable of reconfiguring into different rectifier topologies, the proposed circuit can reconfigure into a switch-based cross-coupling differential drive (CCDD) at low input power and a diode-based hybrid rectifier at higher input power for a wide dynamic range operation. Designed and implemented on a CMOS 65 nm technology, the post-layout result records a peak PCE of 88.7% and a wide PCE dynamic range (PDR) of 16 dBm for PCE >40%. The proposed circuit also demonstrates a -21 dBm sensitivity output across a 1 M ohm output load.