Generalized Analytical Design Equations for Variable Slope Class-E Power Amplifiers

The Class-E power amplifier is widely used because of its high efficiency, resulting from switching at zero voltage and zero slope of the switch voltage. In this paper, we extend our general analytical solutions for the Class-E power amplifier to the ideal single-ended Variable Slope Class-E (Class-E_VS) power amplifier which is switching at zero voltage but not necessarily at zero slope. It is shown that a Class-E_VS power amplifier can have higher tolerance to switch (transistor) output capacitance compared to the normal Class-E power amplifier; this higher tolerance can be exchanged for higher drain efficiency. The presented design equations for Class-E_VS power amplifiers give more degrees of freedom in the design and optimization of switching RF power amplifiers.