A NOVEL DOHERTY POWER AMPLIFIER WITH SELF-ADAPTIVE BIASING NETWORK FOR EFFICIENCY IMPROVEMENT

摘要

A Doherty power amplifier (DPA) with a self-adaptive biasing circuit is presented in this letter. The proposed structure is integrated into the gate biasing network of the peaking power amplifier (PA), and then the gate voltage can be adaptively adjusted with the input power. Due to the presence of this simple but effective circuit, the peaking PA can approach the ideal power transfer characteristic which results in better efficiency than the conventional design with constant biasing. The proposed circuit is implemented and compared with both the conventional DPA and a single Class-AB PA. 12% and 34% power added efficiency improvements are achieved at 6 dB backoff, respectively.