The use of parasitic nonlinear capacitors in class E amplifiers

Abstract

The most common class E amplifier configuration uses a single transistor with a shunt capacitor and a series resonant output filter. Until now a linear shunt capacitance has been assumed. However, to achieve operation at 900 MHz and above, it is of interest to rely solely upon the nonlinear parasitic collector-substrate capacitance of the transistor. An analytical theory for operation at 50% duty cycle and nonlinear capacitance is presented in this correspondence, and the effects on the power capability of the amplifier are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>