A Uniform Digital Predistorter for Concurrent Multiband Envelope Tracking RF Power Amplifiers With Different Envelopes

摘要

This paper proposes a uniform digital predistortion technique for concurrent multiband envelope tracking (ET) power amplifiers (PAs) under various supply modulation types, i.e., different envelopes. It is achieved by successfully dissolving the conventional envelope functions into the proposed model formulas, and derived in detail for typical scenarios, such as peak envelope (PE), average envelope, generalized mean envelope, and weighting factor PE. Because of its model structure, it can earn the advantages of impressive generality, concise forms, low computational complexity, as well as better stability, in comparison to the already published techniques. Experiments using a GaN PA supplied by different ET modulation types have been implemented by employing a dual-band signal with each of 10-MHz OFDM signals at the center frequency of 1.8 and 2.2 GHz, and also by employing a triband signal with each of 5-MHz OFDM signals centered at 1.8, 1.92, and 2.12 GHz, respectively, which can provide a validation for the effectiveness of the proposed method.