Robust beamforming for secured wireless power transfer in MIMO magnetic resonant coupling system: A probabilistic approach

Wireless power transfer (WPT) to support mobile and portable devices is an emerging wireless technique. Among all kinds of approaches, magnetic resonance coupling (MRC) is an excellent one for mid-range WPT, which provides better mobility, flexibility, and convenience due to its simplicity in hardware implementation and longer transmission distances. In this paper, we consider an MRC- WPT system with multiple power transmitters, one intended power receiver and multiple unintended power receivers. We investigate the probabilistic robust beamforming designs and provide efficient algorithms to achieve the local optimums under two different criteria, i.e., total source power minimization problem and min-max unintended receiving power restriction problem. As the problems are quite typical in robust design situations, our proposed robust beamformers can be conveniently applied to other probabilistic robust design problems, thus reduce the complexity as well as improve the beamforming performance. Numerical results demonstrate that the proposed algorithms can significantly improve the performance as well as the robustness of the WPT system.