Subnominal Operation of Class-E Nonlinear Shunt Capacitance Power Amplifier at Any Duty Ratio and Grading Coefficient

This paper presents an analytical model to design a class-E power amplifier under only zero-voltage-switching (ZVS) term with the MOSFET nonlinear drain–source shunt parasitic capacitance that is named as the subnominal operation. The presented analysis is performed under any grading coefficient m of MOSFET body junction diode and any duty ratio D . The grading coefficient m along with the switching duty ratio D are implemented as tuning variables to satisfy design specifications and ZVS term simultaneously. The restriction of selecting the value of m and D for the subnominal operation has a major effect on simultaneously satisfying of load-resistance, operating frequency, and junction capacitance, which is the main result from this study. The obtained laboratory experiment from the fabricated typical circuit under the required output power 6.2 W with the satisfied duty ratio D = 0.4 is used to show the validity of the theoretical predicted expressions.