8-Watt Linear Three-Stage GaN Doherty Power Amplifier for 28 GHz 5G Applications

Abstract

This paper presents a three-stage Ka-band Doherty power amplifier fabricated using 0.15 μm GaN-on-SiC HEMT technology. Peak-power greater than 8-watts, 30 dB of small-signal gain, and over 20% of PAE at 6 dB output back-off has been achieved for 27 to 29.5 GHz operation. In addition, the raw linearity of the Doherty amplifier has been measured using a 400 MHz, 64-QAM CP-OFDM signal with a 9.6 dB peak-to-average-power-ratio. Uncorrected ACPR as good as -40 dBc and EVM as low as 2% demonstrate the potential of this amplifier for 5G applications.