Addressing Efficiency and Linearity With a Single-Ended Class AB Power Amplifier With Optimized Third-Harmonic Termination

The single-ended RF power amplifier (PA) is a standard design approach in the RF engineer’s tool kit, but high efficiency and good linearity may only be achieved if the harmonic terminations and biasing conditions are carefully examined. This application note describes the design of a single-ended PA using Class AB “sweet spots” and an optimized third-harmonic termination based on a design flow that encompassed analysis of the requirements and initial concepts to the simulation, fabrication, and measurement of the built prototype.

The design won first place at the 2016 International Microwave Symposium’s High-Efficiency PA Student Design Competition.