Distortion improvement of power amplifiers with digital predistortion

This paper presents an optimized digital predistortion (DPD) technique based on iterative injecting of distortion components into the baseband signal. The ratio of computation complexity to linearization degree can be regulated by choosing the appropriate number of injections. The proposed DPD technique allows achieving a significant increase in linearization degree and overcoming the distortion compensation limit. Experimental results for a 21-dB gain GaAs power amplifier fed with a 5-MHz digitally modulated signal show significant improvement in spectral regrowth.