Flexible multivariable design procedure for optimum operation of the Class-E amplifier using state space techniques

The Class-E amplifier is a highly efficient tuned switching power amplifier with a linear drain amplitude modulation characteristic ideally suited for high-efficiency amplifier systems (e.g., Kahn-amplifiers). This brief describes a design procedure to determine the circuit elements for optimum operation of the amplifier using state space methods. Finite feed inductance and quality factor of the resonant circuit are taken into account. It is shown that high efficiency can be sustained for a wide variety of element combinations, allowing relaxed demands on the output capacitance of the active device. This is especially useful for high-frequency amplifiers where the maximum operation frequency of a given device is often limited by its intrinsic drain-source capacitance.