Analysis of Gate-Voltage Clipping Behavior on Class-F and Inverse Class-F Amplifiers

This paper describes the influence of gate-voltage clipping behavior on drain efficiency in case of class-F and inverse class-F $(\mathbf{F}^{-1})$ operations under saturated regime. Numerical analysis using a simplified transistor model was carried out. As a result, we have demonstrated that the limiting factor for $\mathbf{class}-\mathbf{F}^{-1}$ operation is the gate-diode conduction rather than knee voltage. On the other hand, class-F PA is restricted by the knee voltage effects. Furthermore, nonlinear measurements carried out on a GaN HEMT support our analytical results.