A fully integrated wideband GaN Doherty power amplifier MMIC with high efficiency for 5G massive MIMO application

In this paper, a 4.5-5.5 GHz wideband high efficiency Doherty power amplifier (DPA) MMIC using a novel compensation technique is proposed. The phase difference and output capacitances of the carrier and peaking PA are analyzed and compensated accurately in a wideband. Thus a sufficient load modulation of the DPA is obtained in a broadband. To verify the proposed design methodology, a broadband high-efficiency DPA MMIC is designed and fabricated in a 0.25 µm GaN-HEMT process for 5G massive MIMO applications. The measurement results illustrate that power added efficiency (PAE) is 44.8%-52.2% at the saturated output power (Psat) of 39.8-40.8 dBm, the PAE at 6-dB output back-off (OBO) is 40.9%-43.9%, and the small-signal gain is 12.5-13.9dB. The proposed DPA demonstrates state-of-the-art saturated and 6-dB back-off PAE among published C-band broadband GaN MMIC DPAs.