A Sub-6 GHz Compact GaN MMIC Doherty PA with a 49.5% 6 dB back-off PAE for 5G Communications

Abstract

This paper presents a sub-6 GHz MMIC Doherty power amplifier (DPA) for 5G communication applications based on a $\pmb{0.25-\mu }\mathbf{mGaN}$ HEMT process. The impedance inverter of the DPA is realized by combining a compact transmission line network with two shunt capacitors. Also, the ratio of power cells in the main and auxiliary amplifiers is optimized to achieve a high efficiency in output power back-off. The measured peak output power and $\mathbf{P}_{\pmb{1}\mathbf{d}\mathbf{B}}$ are 38.7 and 32.1 dBm, respectively at 5.9 GHz. The power-added-efficiency (PAE) at a 6-dB output power backoff is up to 49.5%.