High efficiency class B GaN power amplifier with dynamic gate biasing for improved linearity

This reported work demonstrates a significant improvement in linearity of an S-band 10 W GaN class B power amplifier biased at the pinch off point by using an appropriate gate bias technique. A simple processing of the envelope of the input RF signal is applied to achieve a time varying gate bias voltage which is pulled-up a little above the pinch off voltage when the instantaneous power of the input RF signal is low. This technique enables enhancement of the linearity of the power amplifier with a very minor impact on power added efficiency performances. Almost 6 dB improvement of ACPR for a 2MSymb/s 16QAM signal at 2.5 GHz has been demonstrated.