A High-Linearity Quasi-Darlington Amplifier with Sub-Degree AM-PM for WLAN Applications

This paper presents a power amplifier (PA) with a proposed High-Linearity Quasi-Darlington (HLQD) structure implemented in the GaAs HBT process. The HLQD enables AM-PM compensation between transistors operating at different bias states while maintaining minimal AM-AM distortion. The power stage PA prototype based on HLQD, operating in the 5.6-6.7 GHz frequency band, achieves less than 1° AM-PM distortion with AM-AM variation less than 0.5 dB, with an output power around 1W, and 38% peak power-added efficiency. It demonstrates an average output power of 17.8 dBm while meeting -40 dB EVM requirements under the MCS11 160 MHz 1024 QAM modulated signal, showing promising potential for Wi-Fi 6/6E/7 applications.