A 3.3-4.1 GHz Wideband Doherty Power Amplifier MMIC with Novel Bandwidth Expansion Technique

In this paper, a novel 3.3-4.1 GHz wideband two-stage Doherty power amplifier (DPA) MMIC fabricated in a 250 nm Gallium-Nitride (GaN) MMIC process is presented. In order to break the bandwidth limitation of traditional DPAs, a novel bandwidth expansion technology including the broadband active load modulation network and phase compensation network is proposed. The measurement results show that the fabricated DPA chip can achieve 39.7-40.7 dBm saturation output power (Psat) in the range of 3.3-4.1 GHz. The power added efficiency (PAE) at saturation is 45.7%-51.1%, and the PAE of 40.2%-43.80% can be achieved at the output power rollback of 6dB, and the small signal gain is 22.7-26.8 dB. The proposed DPA demonstrates high saturation and 6dB back-off PAE among published C-band wideband GaN DPA MMICs, which can be widely used in the 5G massive MIMO applications.