An Integrated GaAs HBT Doherty Power Amplifier for Wi-Fi 6

This paper presents an integrated three-stage Doherty power amplifier for Wi-Fi 6 applications operating in the 5-6.2 GHz frequency range. The H20U-C4 GaAs HBT technology available at WIN semiconductors is chosen for its excellent linearity and good efficiency features. The power cells adopted as active devices are designed to be thermally and RF stable through the proper selection of ballast resistors and capacitors. A comprehensive measurement campaign was conducted, demonstrating an output power, efficiency and gain larger than 32 dBm, 35% and 22.5 dB, respectively, at saturation. At 6 dB of output back-off the efficiency is better than 20% all over the specified bandwidth. Moreover, when tested with a 20 MHz MCS11 signal having 10 dB PAPR, the DPA provides an average output power of 22 dBm with an efficiency and EVM of 11% and -25 dB, respectively.