Class BJF⁻¹: Pushing the boundaries of the performance of RF Power Amplifiers.

A new design space of contiguous mode amplifiers straddled in the centre of the Smith Chart, by Class J at one end and Class CCF⁻¹ at the other, is presented. The waveforms require tuning of the second harmonic of the voltage and upto the third harmonic of the current, to derive the full benefit of harmonic tuning. This class is naturally realised by tuning the output capacitance C_DS of a GaN transistor, compared to the counterpart in class CCF. We have demonstrated several prototypes in this class with outstanding performance of efficiency, output power, bandwidth, and linearity.