Optimizing the Doherty Amplifier: Design of a 3-GHz GaN Doherty Amplifier Achieving 60% Efficiency

The Doherty amplifier, invented by William H. Doherty, has been around since 1936 [1]-[3]. The amplifier has seen a resurgence in recent times, in part due to the work of Steve Cripps [4]. The Doherty?s ability to achieve high efficiency over a wide band of frequencies and its high linearity characteristics make it an effective architecture for applications ranging from telecommunications to cellular base stations to the defense industry. The Doherty amplifier formed the basis of design for the author's entry in the 2019 IEEE Microwave Theory and Techniques Society International Microwave Symposium (IMS2019) High-Efficiency Power Amplifier Student Design Competition (SDC) [5].