RF-to-DC Conversion Circuit with Configurable Impedance Matching Circuit for RF Energy Harvesting in 65nm CMOS Technology

This paper presents a multiband rectifier with a configurable impedance matching circuit and a low-dropout (LDO) voltage regulator for RF energy harvesting applications at 1.8GHz, 2.1GHz, and 2.4GHz frequency bands. The configurable impedance matching circuit allows the shifting between the three target impedance settings to optimize the system performance in each frequency band. The rectifier circuit is coupled with an auxiliary PMOS transistor for threshold voltage cancellation, enhancing the DC extraction efficiency of the conventional circuit. The LDO voltage regulator circuit is designed with Miller compensation to ensure stability and prevent oscillations in the control loop and a feedback capacitor to improve its transient response. Simulation results show that the overall efficiency of the proposed RF -to-DC conversion circuit is 75.4 % with power dissipation of 6.71 mW, average peak PCE of 63.7 %, and average APE of 9.4 % at the three target frequencies for a regulated DC output voltage of 1V with an output load resistance of 50k Ω. The proposed conversion circuit is implemented using 65nm CMOS technology.