A Ka-band Three-Stage GaN MMIC Doherty Power Amplifier with Wideband Tee-line Doherty Network for 5G Applications

This paper presents the design and measurement of a Ka-band three-stage GaN microwave monolithic integrated circuit (MMIC) Doherty power amplifier (DPA) with wideband Tee-line Doherty network architecture for 5G applications using a 0.15-μm gate-length GaN technology. The fabricated GaN MMIC DPA achieves a peak output power greater than 36.2 dBm and PAE greater than 18.4% at 9 dB output power back-off over 26–30 GHz band. Additionally, the fabricated GaN MMIC DPA achieves an adjacent channel power ratio less than -29 dBc and error vector magnitude less than 6.9% under a 64-QAM CP-OFDM of 100 MHz bandwidth with 9.8 dB peak-to-average-power-ratio over 26.5–29.5 GHz band.