Envelope Preformulation Digital Predistortion for Concurrent Dual-Band Power Amplifiers with Improved Performance and Stability

This letter proposes a novel envelope preformulation digital predistortion technique to linearize concurrent dual-band (DB) power amplifiers (PAs), presenting improved stability/performance, and easier implementation compared to conventional methods. The concurrent DB system was implemented on a GaN Doherty PA by employing two 20-MHz orthogonal frequency division multiplexing signals at the center frequency of 2.25 and 2.45 GHz, respectively. Experimental results have shown great effectiveness of the proposed method, especially when the PA is pushed into highly nonlinear regions, which is very promising for multiband applications in the future communication systems.