Idealized Operation of the Class E Tuned Power Amplifier

Absfracr-The class E tuned power amplifier consists of a load network and a single transistor that is operated as a switch at tbe carrier frequency of tbe output signal. ‘zbe most simple type of load network consists of a capacitor shunting tbe transistor and a series-tuned output circuit, which may bave a residual reactance. Circuit operation is determined by tbe transistor when it is on, and by the transient response of the load network when tbe transistor is off. The basic equations governing amplifier operation are derived using Fourier series techniques and a high-Q assumption. These equations are then used to determine component values for optimum operation at an efficiency of 100 percent. Other combinations of component values and duty cycles which result in lOO-percent efficiency are also determined. ‘fbe barmouic structure of tbe collector voltage waveform is analyzed and related amplifier configurations are discussed. While tbis analysis is directed toward the design of bigbefficiency power amplifiers, it also provides insight into tbe operation of modern solid-state VHF-UHF tuned power amplifiers.