Comprehensive Analysis of Input Waveform Shaping for Efficiency Enhancement in Class B Power Amplifiers

Over the years, different high efficiency power amplifier (PA) design techniques have been proposed and implemented which eliminate input non-linearity considering its negative impact on PA output power and efficiency. This work rather exploits input non-linearity to improve PA efficiency. A generic analysis of a Class B PA under input non-linearity is presented opening the scope of input second harmonic manipulation to improve PA performances. This renders extended and new design space of second harmonic source termination to high efficiency PA design. Theoretical analyses are well supported with load-pull measurement results of a 0.7 mm and a 24 mm GaN devices where about 4.5% drain efficiency improvement compared to conventional Class B PA is observed.