Transmission-line-based multi-way lossless power combining and outphasing system

This paper presents a non-isolating multi-way outphasing and power combining system that achieves nearly resistive loading of branch amplifiers over the entire output power range through a combiner network comprising only transmission line sections. We derive a design methodology and describe an outphasing control law that selects control angles to minimize the peak susceptive loading of the branch PAs over a specified output power range. The approach is demonstrated in a 2.14-GHz, four-way outphasing amplifier system that achieves >60% drain efficiency over a 6.2-dB output power range.