Effect of the loaded quality factor on power efficiency for CMOS class-E RF tuned power amplifiers

An analytical expression for the harmonic distortion and power efficiency for class-E power amplifiers is derived. By considering the nonideal behavior of the switching device, we explore the dependence of power efficiency on the quality factor of the resonant circuit, as well as the current decay angle of the active device. The result is very useful since it predicts the power efficiency in terms of circuit parameters. The analytical expression is supported by good agreement with circuit simulations.