Outside Nominal Operation Analysis and Design Considerations of Inverse-Class-E Power Amplifier

In this paper, design and analysis using analytical expressions for the inverse class-E power amplifier (PA) operating at the outside nominal operation, i.e., class- $\text{E}_{\mathrm{n}}$ PA, is presented. This operation is defined as nonzero current switch (n-ZCS) and nonzero-derivative-current switch (n-ZDCS) conditions. The generalized design equations as a function of design specifications, load resistance, and a given dc-supply voltage are derived. Two degrees of the design freedom achieved thanks to n-ZCS and n-ZDCS that are utilized for the simultaneous satisfaction of design specifications, such as peak-switch-voltage and peak-switch-current along with a given load resistance. The output power capability is affected by n-ZCS and n-ZDCS conditions, which can be obtained in the desired value using the controlled adjustment of introduced deviation parameters. In order to prove the validity of the proposed design methodology, an inverse class-E PA operating in 2 GHz with output power of 23 dBm is implemented in 0.25- $\mu \text{m}$ AlGaAs–InGaAs pHEMT technology. There is a close agreement between the theoretical and simulation results and the measurements of the fabricated prototype PA, which proved the validity of the obtained design expressions.