Digital predistortion for a dual-band envelope-tracking power amplifier with reduced bandwidth requirement for rf and envelope paths

This paper proposes a novel digital predistortion technique to effectively linearize concurrent dual-band (DB) envelope tracking (ET) power amplifiers (PAs) with reduced bandwidth requirements for both RF and envelope paths. Based on a gallium-nitride (GaN) ET PA, the concurrent DB system was implemented by employing two 5 MHz OFDM signals at the center frequency of 2.0 GHz and 2.6 GHz with linearization bandwidth that is limited to only 15 MHz. The PA in-band and out-of-band performance was evaluated with an improvement of 26 dB and 21 dB for normalized mean square error (NMSE) and adjacent channel power ratio (ACPR), respectively.