Implementation of Distributed Microwave Power Transfer with Backscatter Feedback and LM-Based Phase Optimization

To realize a distributed cooperative power transfer system, reduction in the phase optimization time is a major issue. For this purpose, backscatter-based feedback has been proposed as a fast feedback method for the received signal strength of the target node. On the other hand, as existing phase optimization algorithms based on backscatter feedback optimize each Tx antenna, the time required for phase optimization increases as the number of Tx antennas increases. We propose a method that combines backscatter-based feedback and levenberg-marquardt (LM) optimization to further speed up phase optimization. Based on the proposed method, the phase set suitable for the proposed method and initial parameters of the nonlinear regression algorithm are verified. The experiments showed that phase sets based on a continuous function suppressed the frequency spreading caused by the switching of phase sets and the determination of the initial solution based on the received strength improved the received power by 2.5 dB and accelerated the calculation time of the LM method by 10 ms.