High efficiency and high power GaN HEMT inverse class-F synchronous rectifier for wireless power applications

Abstract

Experimental results are shown for a high power GaN RF synchronous rectifier configured in an inverse class-F circuit topology. The rectifier is constructed from an inverse class-F amplifier by adding feedback from the output to the input and then driving the output node as a RF input and replacing the DC drain supply with a DC load resistance. Both the amplifier and rectifier duals are tested under identical source power conditions. The amplifier has a drain efficiency of 84.3% for an output power of 10 W, while the rectifier has a rectification efficiency of 85% for a DC output power of 10.15 W. To the best knowledge of the authors, this is the highest reported power for a RF synchronous inverse class-F rectifier. The rectifier has a large dynamic range, and at 20 dB back-off, the efficiency is 48.5% for 100 mW of RF input power.