Modeling and implementation of high efficient Class-F−1 power amplifier

In this paper, the physical constraint effects imposed on the knee voltage along with the variation of optimum load resistance for high efficient Class-F^-1 amplifier are analyzed. For the accurate analysis, the new current waveform models are identified, and the realistic approach incorporating with a non-zero knee voltage and a voltage dependent-nonlinear capacitance is employed to derive the voltage waveforms of the amplifiers. With this knowledge, we provide the direction to optimize the design and the ultimate comparison of performances. The analytic result is further verified by the measured results of 3.54GHz Class-F^-1 amplifier using a commercial 60W PEP GaN device. The experiment results show that a Class-F^-1 amplifier operates at drain efficiencies of 69.9% at saturated output powers of 47.4dBm. This performance has excellent agreement with the predicted analysis in our operation frequency.