A Novel Approach to Studying Class E Power Amplifiers with a Complex Impedance Load

In contrast to the known publications devoted to the design of class
$E$
power amplifiers (PAs) and limited to the consideration of a particular case of a real load, this paper considers an analytic method of calculation of class E PA when operating on a complex load. The relations allowing to determine real and imaginary parts of the input impedance of the load proceeding from the transistor soft-switching condition are obtained. The adequacy of the analytic model is confirmed by simulation, which shows that the relative error in the calculation of the main characteristics of the PA does not exceed 1.5%. The obtained relations can be used to synthesize a matching circuit that ensures high efficiency of the PA when operating in the frequency band.