Patent ID: 7961048

Claim:
A power amplifier system, comprising: a carrier amplifier, wherein the carrier amplifier is connected to a first quarter wave transformer at the input of the carrier amplifier; at least one peaking amplifier connected in parallel with the carrier amplifier; a first differential combining structure, wherein the first differential combining structure includes a first plurality of quarter wave transformers that are configured to combine respective first differential outputs of the carrier amplifier in phase to generate a first single-ended output signal; and a second differential combining structure, wherein the second differential combining structure includes a second plurality of quarter wave transformers that are configured to combine respective second differential outputs of the at least one peaking amplifier in phase to generate a second single-ended output signal, wherein the second plurality of quarter wave transformers are arranged to provide an equivalent cumulative delay and phase shift provided by the first quarter wave transformer and the first plurality of quarter wave transformers such that the first single-ended output signal and the second single-ended output signal are combinable in-phase to provide an overall output.