A 90W High-Efficiency Four-Way Doherty Power Amplifier with 37.8% Fractional Bandwidth over a 15 dB Power Back-off Range

This work presents the synthesis, design, and implementation of a new four-way Doherty architecture with an easy-to-implement 2×2 output combiner. By careful selection of the drive profiles of the main and the three peaking amplifiers, the proposed four-way DPA achieves smooth RF output power and efficiency over a very large fractional bandwidth and power back-off range. For validation purposes, a 90W GaN four-way DPA has been realized for the 0.9 GHz band. The measurement results show more than 49.5dBm saturated output power over a 37.8% relative bandwidth with drain efficiency ranging from 54.0% to 59.3%. At 15 dB power back-off, the efficiency is maintained within the range of 41.3% to 51.1%.