Design of High Efficiency High Back-off Doherty Power Amplifier Based on Hybrid Optimization

This paper proposes a novel design methodology for high-efficiency Doherty power amplifier (DPA) by leveraging harmonic control and hybrid optimization techniques, the proposed approach addresses the trade-off between harmonic suppression and back-off efficiency inherent in conventional designs. Multiple harmonic impedance modulation is implemented to optimize the efficiency through the asymmetric structure of double-L structure in the main circuit and single-L structure in the auxiliary branch, Additionally, the load reflection coefficients of the main circuit are constrained and optimized to enhance the power amplifier's wide dynamic range performance. The optimization algorithm is utilized to hybrid optimize the fundamental and harmonic load impedance, main path load reflection coefficient, power, efficiency and gain of the Doherty power amplifier. To validate the proposed methodology, a 2.0 GHz high efficiency high back-off Doherty power amplifier is designed and implemented. Measurement results demonstrate that the designed power amplifier achieves a saturated output power of 44 dBm, a saturated output efficiency of 75% and a back-off efficiency of 65%.