Doherty's Legacy: A History of the Doherty Power Amplifier from 1936 to the Present Day

Eighty years ago, William Doherty invented a PA architecture that has played-and will continue to play-an important role in the development of energy-efficient radio transmitters for a variety of wireless communication applications. Although the original concept is still equally valid, the development of new semiconductor processes and digital signal processing techniques has served as a basis for an evolution of the DPA topology into the 21st century. The need for energy-efficient power amplification will be further emphasized in future wireless systems (5G and beyond) through the projected exploration of dense-antenna arrays and millimeter-wave frequencies. Recent developments of the Doherty concept make it one of the most attractive candidates for realizing energy-efficient wireless systems into the future.