Design of linear and efficient power amplifiers by generalization of the Doherty theory

The Doherty power amplifier (PA) is now established as one the most widely adopted architectures for enhancement of energy efficiency in wireless communication transmitters. More than 80 years after its invention, most of today's implementations still rely on the original circuit topology. This paper describes a new Doherty solution continuum that is revealed when the original λ/4 combiner is replaced by a generic, analytically derived, lossless combiner network. As a result, novel Doherty PA solutions that in practice are both more efficient and more linear are enabled. A variety of practical design examples are included to illustrate how the presented techniques can enable enhanced performance in both traditional and emerging mm-wave 5G wireless communication transmitter applications.