A 3.3-3.6 GHz Doherty Power Amplifier in GaAs HBT Technology with an Asymmetric Structure

This work proposes a GaAs HBT Doherty power amplifier (DP A) with a compact size for 5G application. Different from most GaAs HBT DP As, this DPA operates in the asymmetric mode with an integrated three stages for higher gain, and the phase alignment between the carrier and peaking amplifier is enhanced by employing input, inter-stage and output matching network. The fabricated Doherty P A achieved a high gain of 32.5-34.1 dB and P1dB of 34-34.5 dBm. The 42.8-45 % and 28.7-30.9 % PAE are obtained at P1dB and 7 dB PBO under a continuous-wave signal test across 3.3-3.6 GHz respectively. At 3.5 GHz, a 10-MHz two-tone signal is also applied to the proposed DP A. The measured IMD3 is less than -30.2 dBc without any linearization.