A 5.8-GHz Bidirectional and Reconfigurable RF Energy Harvesting Circuit With Rectifier and Oscillator Modes

A bidirectional circuit that can be reconfigured as a receiver for rectifying radio-frequency (RF) power for energy harvesting, and as a power oscillator for transmission, is proposed. The circuit is compact and suitable for integration in time-division multiplexed wireless sensors. A design concept based on time-reversal duality theory is employed to reuse the same circuit elements for both the oscillator and the rectifier modes by reconfiguring power How between the dc and RF ports. A proof-of-concept prototype circuit using a high-efficiency class-DE circuit topology is implemented in a 65-nm CMOS technology. The circuit operates at a frequency of 5.8 GHz, and the measured peak efficiency is greater than 50% in both operating modes.