Photovoltaic-assisted CMOS rectifier circuit for synergistic energy harvesting from ambient radio wave

In this study, we realized efficient energy harvesting from ambient radio waves using a photovoltaic (PV) assisted CMOS rectifier. The rectifier operates truly synergistically. A p-n junction diode acting as a PV cell converts light energy to a dc bias voltage, which compensates the threshold voltage of the MOSFETs and enhances the RF to DC power conversion efficiency (PCE) of the rectifier even under extremely low input power condition. Under ambient light conditions, a PCE greater than 20% was achieved at an RF input power, frequency, and output load of -20 dBm, 920 MHz and 47 kΩ, respectively, which is twice the value obtained from a conventional rectifier without PV assistance.