A Fully Integrated C-Band GaN MMIC Doherty Power Amplifier with High Gain and High Efficiency for 5G Application

This paper presents a fully integrated C-band GaN MMIC Doherty power amplifier (DPA) for 5G application. A driver stage is employed in both the main and auxiliary branches to boost the power gain. A compact low-loss output network is designed to realize high efficiency and minimize chip size. The fabricated DPA exhibits a power gain of 17 dB, a saturated output power of 41.3 dBm, a saturated PAE of 61%, and a 6-dB back-off PAE of 47% at 4.7 GHz, with a compact size of 3 mm × 2.5 mm. Moreover, the 6-dB back-off PAE is better than 40% across a large bandwidth from 4.4 GHz to 5.1 GHz. Using a 40-MHz LTE signal at the carrier frequency of 4.7 GHz, the measured adjacent channel power ratio is -45 dBc at the average output power of 33.7 dBm after applying digital predistortion.