A novel method for designing an inverse Class F power amplifier by controlling up to fifth harmonic

In this paper, a method of shaping waveforms at drain for designing an inverse Class-F power amplifier is presented. The second and fourth harmonics are controlled by a simplified structure by employing the bias circuit. Then by tuning the phase of the second and fourth harmonic, and also third and fifth harmonic components in the load, the de-embedded voltage and current waveforms at drain are shaped into approximate half-sinusoidal and square, respectively. With this kind of waveform, less power dissipation can be achieved because of less overlap between the waveforms. Load pull simulation predicts 82% PAE by this method with optimal load and source impedance. The fabricated circuit is exhibited and measured. PAE reached 72.4% with 38.4 dBm output power at one-tone frequency 2.14GHz.