Generalised frequency-domain analysis of microwave Class-E power amplifiers

A frequency-domain method is formulated for the analysis of arbitrarily loaded Class-E circuits based on the harmonic balance technique. General loading requirements for optimum Class-E mode of operation are derived. Essential design information such as effects of turn-on resistance, harmonic terminations and idealised load-pull contours are given. The theoretical findings are then transformed into a straightforward design procedure. A 1.8 GHz experimental amplifier was constructed, which shows a state-of-the-art drain efficiency of over 90% from a 0.5 to 4 V supply voltage