Simulation and optimization of class-E power amplifiers with extended impedance method

This article introduces a novel perspective to the study of class-E power amplifier by extending the scope of electrical impedance. Owing to this extension, the electrical property of the active switch in a class-E circuit is taken as a special kind of impedance. Consequently, it is possible to regard a whole class-E circuit as combination of impedances, whose total impedance is obtainable according to the existing circuit laws. When subjected to a DC supply voltage, the steady-state response of the total impedance can be directly obtained with the Ohm´s law, regardless of the transient state. In addition, based on the formulation, regarding maximum power conversion efficiency as its design objective, class-E optimization is also carried out. Since no waveform equation is required for both simulation and optimization, these simulation and optimization are more concise and efficient than those in all of the previous studies.