Joint circuit-level and digital predistortion strategies for enhancing the linearity-efficiency tradeoff of Doherty power amplifiers

This paper begins by discussing the main circuit-level sources of distortion exhibited by multiband and broadband Doherty power amplifiers (DPAs). It also highlights solutions for minimizing their unwanted effects on DPA performance when driven with carrier aggregated signals. Subsequently, it describes the digital predistortion (DPD) system needed to mitigate the residual distortions and improve the achievable linearity-efficiency tradeoff. Finally, the challenges to applying the DPD technique to linearizing 5G DPAs will be surveyed.