A 2.45 GHz High Efficiency CMOS RF Energy Harvester with Adaptive Path Control

In this research work, a reconfigurable 2.45-GHz RF-DC converter realized in a 180-nm complementary metal-oxide semiconductor (CMOS) technology is proposed to efficiently harvest electromagnetic energy. The proposed circuit is composed of a low-power path rectifier, a high-power path rectifier, and an adaptive path control (APC) circuit. The APC circuit is made-up of a comparator, two switches, and an inverter. The APC circuit senses the output voltages of the low-power path and the high-power path rectifiers and generates a control signal to automatically switch the proposed circuit between the lower-power path and the high-power path operation depending upon RF input power level. The proposed circuit obtains more than 20% measured power conversion efficiency (PCE) from −6 dBm to 11 dBm input power range with maximum efficiencies of 41% and 45% at 1 and 6 dBm input powers, respectively, for 5 kΩ load resistance. In addition, the proposed circuit shows excellent performance at 900 MHz and 5.8 GHz frequencies.