Broadband dual-input doherty power amplifier design based on a simple adaptive power dividing ratio function

Abstract

In this paper, a simple adaptive power dividing function for the design of a dual-input Doherty power amplifier (DPA) is presented. In the presented approaches, the signal separation function (SSF) at different frequency points can be characterized by a polynomial. And in the practical test, the coefficients of SSF can be determined by measuring a small number of data points of input power. Same as other dual-input DPAs, the proposed approach can also achieve high output power and back-off efficiency in a broadband operation band by adjusting the power distribution ratio flexibly. Finally, a 1.5–2.5 GHz high-efficiency dual-input Doherty power amplifier is implemented according to this approach. The test results show that the peak power is 48.6–49.7dBm, and the 6-dB back-off efficiency is 51.0–67.0%, and the saturation efficiency is 52.4–74.6%. The digital predistortion correction is carried out at the frequency points of 1.8/2.1GHz, and the adjacent channel power ratio is lower than −54.5dBc. Simulation and experiment results can verify the effectiveness and correctness of the proposed method.