Wideband high efficiency digitally-assisted envelope amplifier with dual switching stages for radio base-station envelope tracking power amplifiers

This paper presents a novel envelope amplifier architecture to improve the overall efficiency of wideband high linearity envelope tracking power amplifiers (PAs). We show here a technique to increase the efficiency of the envelope amplifier while maintaining the amplifier´s bandwidth. The overall system was demonstrated using a GaAs high voltage HBT PA. For a variety of signals ranging from 6.6dB to 9.6dB PAR and up to 10MHz bandwidth, the overall system PAE reached above 50%, with a normalized RMS error below 5% and ACLR1 of −50dBc with memory-less digital pre-distortion, at an average output power above 19W and gain of 10dB. The efficiencies obtained are the best ever reported, to our knowledge, for envelope tracking base station amplifiers for these signals.