Effect of Nonlinearity of Parasitic Capacitance on Analysis and Design of Class E/F3 Power Amplifier

In this paper, the analysis and comparison of a Class-E/F-3 power amplifier with nonlinear and linear shunt capacitance at 50% duty ratio are presented. An analytical analysis for nonlinear and linear shunt capacitance is presented, and its effects on the performance of the power amplifier are discussed. The different parameters, such as series reactance, peak switch voltage, and power output capability are compared for power amplifiers with linear and nonlinear shunt capacitance. Two design examples of the Class-E/F-3 power amplifiers with IRF530 MOSFETS and lumped elements at an operating frequency of 4 MHz are analyzed. The PSpice simulation and measurement for the power amplifier with nonlinear shunt capacitance have been done. The results agree with the analytical expressions that show the validity of the analytical expressions derived at zero-voltage switching and zero derivative voltage switching conditions.