Joint mitigation of nonlinearity and modulator imperfections in dual‐band concurrent transmitter using neural networks

Abstract

Reported, for the first time is a predistortion scheme for a concurrent dual-band transmitter with a dual-band concurrent Doherty power amplifier in the presence of modulator I/Q imbalance and DC offsets. Inverse PA modelling for predistortion is achieved using real valued time delayed neural networks. The model has been validated for a 10 W GaN based dual-band concurrent Doherty power amplifier for wideband code division multiple access signals at 1960 and 3500 MHz, respectively, and an adjacent channel power ratio improvement of 18 dB is reported.