Consideration of impact of GaN HEMT for class E amplifier

This paper demonstrates GaN HEMT as the transistor switch for 13.56 MHz class E amplifier. It is shown that GaN HEMT has capability of realizing very high efficiency class E amplifier at higher frequency than Silicon MOSFETs. Problem of negative threshold voltage, i.e., "normally on" characteristics, is considered. It is considered using second voltage supply, GaN HEMT can be driven properly. Experimental demonstration of 13.56 MHz 1 W class E amplifier achieved 82% efficiency.