High-Efficiency Four-Stage Class-E Doherty Amplifier for W-CDMA Base Stations

Abstract

A high-efficiency four-stage class-E Doherty power amplifier for W-CDMA base stations has been developed. Its final stage amplifier, the symmetrical Doherty amplifier using an internally class-E matched GaN packaged device, achieves 15 dB gain and 58.4% CW drain efficiency at 6 dB output back-off from 170 W (52.3 dBm) saturated power. The four-stage 60 dB-gain amplifier, including an output isolator, achieves 42.7% overall efficiency at 28 W (44.5 dBm) average output power, while maintaining -52 dBc ACLR at 5 MHz offset with DPD for a WCDMA 4FA signal with 6.8 dB PAPR measured at .01% probability on CCDF.