Improved design technique of a microwave class-E power amplifier with finite switching-on resistance

The class-E amplifier is a highly efficient amplifier for microwave power applications. Due to the complexity involved, previous analytical efforts assumed either zero switch resistance and/or infinite drain (collector) inductance, which resulted in less than optimum designs. In this paper, we take the effect of both the finite switching-on resistance and finite drain inductance into account, and present an improved and optimized design technique. A 1.9 GHz CMOS class-E power amplifier, which can deliver 0.25 W of output power, was analyzed as an example of this new design technique. Excellent agreement between the theoretical analysis and simulation results is reported, pointing the way towards the optimized design of the class-E stage for microwave applications.