Design of rectifier with comparator using unbalanced body biasing for wireless power transfer

This paper presents a rectifier with comparator using unbalanced body biasing for wireless power transfer in 0.11μm RF CMOS process. The proposed rectifier is composed of MOSFETs and two comparators. The comparator is used to reduce reverse leakage current occurring when the load DC voltage is higher than input RF voltage. For this purpose, unbalanced body biasing is devised. 0.837V sinusoidal RF input is rectified to 0.755V DC voltage, leading to 90% voltage conversion efficiency (VCE) at maximum. 13.56 MHz signal is used for input, and this circuit works up to 150 MHz signal keeping above 80% VCE.