Effect of offset lines in Doherty power amplifiers

Abstract

In this paper, main and peaking voltages of a Doherty power amplifier are derived by means of the chain parameters of the output section to analyze the effect of the offset lines on the drain efficiency. It is shown that the main branch offset line dominates the drain efficiency. Furthermore, it is exhibited that moderate offset mismatch at the peaking branch has no significant influence on the output power performance of the amplifier. A 100W GaN Doherty power amplifier is realized to experimentally verify the results.