Power losses and efficiency of class-E power amplifier at any duty ratio

This paper presents an analysis of the effect of duty ratio on power loss and efficiency of the Class-E amplifier. Conduction loss for each Class-E circuit component is derived and total amplifier losses and efficiency are expressed as functions of duty ratio. Two identical 300-W Class-E amplifiers operating at 7.29 MHz are designed, constructed, and tested in the laboratory. Dependence of total efficiency upon duty ratio when using real components is derived and verified experimentally. Derived loss and efficiency equations demonstrate rapid drop in efficiency for low duty ratio (below approximately 30%). Experimental results very closely matched calculated power loss and efficiency.