Efficient supply power control by PWM technique for microwave wireless power transfer systems

A pulse-width modulation (PWM) technique has been applied for efficient supply power control in microwave wireless power transfer systems. For this evaluation, a high-efficiency GaN HEMT amplifier and rectifier operating at the 5.4-GHz band have been fabricated, which are used as a DC-to-RF and RF-to-DC converter, respectively. The fabricated amplifier and rectifier delivered a maximum drain efficiency of 82% at 5.43 GHz and a maximum RF-to-DC efficiency of 78% at 5.45 GHz, respectively. In the evaluation of the supply power control, a total system efficiency of more than 47% was maintained for a supply power change from 90 to 860mW by using the PWM technique.