Integrated power amplifiers for use in wireless communication devices

A power amplifier system, comprising:

• a single carrier amplifier, wherein the single carrier amplifier is connected to an input quarter wave transformer at the input of a carrier amplifier;
• at least one peaking amplifier connected in parallel with the single carrier amplifier;
• a first differential combining structure, wherein the first differential combining structure includes a second quarter wave transformer and a third quarter wave transformer that are each respectively connected at one end to respective first differential outputs of the carrier amplifier and at another end to each other to form a first single-ended output, wherein the second and third quarter wave transformers operate substantially 180 degrees out of phase with respect to each other;
• and
• a second differential combining structure, wherein the second differential combining structure includes a first path that includes two output quarter wave transformers connected in series, and a second path that includes two output quarter wave transformers connected in series, wherein a first one of the two quarter wave transformers in both the first and second paths operate substantially 180 degrees out of phase with respect to each other, wherein a second one of the two output quarter wave transformers in both the first and second paths are phase-equivalent to the input quarter wave transformer, wherein a respective one of second differential outputs of the at least one peaking amplifier are provided as inputs to the respective first and second paths, wherein outputs from the first and second path are combined to generate the second single-ended signal, wherein the first and second single-ended signals are combinable in-phase to generate an overall output signal.