Subsampling Feedback Loop Applicable to Concurrent Dual-Band Linearization Architecture

This paper demonstrates an energy-efficient and low-complexity subsampling receiver adopted in the feedback loop of the dual-band power amplifier (PA) linearization architecture. The challenges and issues on finding the valid subsampling frequencies in nonlinear system are discussed, and a systematic approach for finding valid subsampling frequencies is presented. The subsampling-based receiver is applied as a proper solution for the feedback loop of the dual-band linearization architecture. It is shown that the subsampling feedback loop reduces the complexity and the cost of the dual-band linearization architecture. The simulation and measurement results show the proper functionality of the presented technique and demonstrate a good linearization performance. The measurement results show that when using this method, more than 15-dB improvement in normalized mean squared error and more than 17-dB improvement in adjacent channel power ratio are achieved for a wideband class-AB PA, compared with the unlinearized method.