Input-Power-Synchronous Adaptively Biased Wide-Dynamic-Range High-Efficiency Rectifier with Zero-Threshold GaAs HEMTs

A wide-dynamic-range high-efficiency rectifier configuration has been developed for microwave wireless power transfer systems. The high-efficiency operation is shifted to a higher input power region by decreasing the gate-bias voltage of the transistor rectifier, whose circuit is carefully adjusted. Thus, according to an input power increase, a suitable gate-bias voltage was supplied to the high-efficiency transistor rectifier from a transistor rectifier circuit generating a negative DC voltage. The fabricated rectifier with zero-threshold GaAs HEMTs exhibited RF-to-DC power conversion efficiencies of more than 60% and 70% for input powers from 0 to 25 dBm and 9 to 24 dBm, respectively.