Wide dyanmic range 2nd order nested envelope tracking power amplifier with GaN modulator

In this paper, a wideband envelope tracking base-station power amplifier with a 2^nd order nested scheme utilizing GaN devices for both linear and current source array was presented, which boosts envelope tracking power amplifier efficiency over wide dynamic range. Tuneable peak efficiency points in the 1^st order nested structure make a flexible efficiency adaptation for various wideband modulated signal besides efficiency boosting. Further, the 2^nd order nested scheme was proposed to enhance power saving mode for base station, e.g. LTE/LTE-A, reducing the OPEX by lower power operation according various traffic profiles.