Linearization and EVM enhancement of an efficient class J amplifier for 3G and 4G mobile communication signals

This paper presents the synergistic combination of an efficient power amplifier design with a novel approach for the digital predistortion that, in addition to reducing spectral regrowth, is optimized to deal with the in-band distortion. The proposed linearization is based on a pre-processing filter followed by a memoryless nonlinear block, and is easily inserted in an OFDM system. The experimental validation has been accomplished with 3GDPP WCDMA and LTE signals in a class J amplifier based on a 15 W GaN device. Measurements show improvements over 10 dB in ACPR and one-point reduction of EVM compared to other widely-used approaches.