A linearized Doherty amplifier using complex baseband digital predistortion driven by CDMA signals

摘要

This work proposes a digitally linearized Doherty amplifier for CDMA applications. A fully digital complex baseband predistorter is used to improve the linearity of the amplifier over the whole input power range. This results in an improvement of the linearity of the Doherty amplifier without degrading its power efficiency. Experimental validation was carried on a designed 1-watt power Doherty amplifier operating at 1900 MHz. The performance of the linearized Doherty amplifier (LDA) was evaluated under a cdma2000 SRI signal. A power added efficiency of 50% was obtained with an ACPR level better than 35 dBc.