Simultaneous Wireless Information And Power Transfer: An S-Parameter Approach

With the rapid growth of the Internet of Things (IoT), inductive coupling is gaining recognition as a promising technique for efficient short and middle-distance wireless power transfer. In this paper, a practical multiple-input multiple-output (MIMO) simultaneous wireless information and power transfer (SWIPT) system using inductive coupling is considered. The conventional circuit solving approach quickly becomes intractable when MIMO transmission is considered. To overcome this problem, we propose a "black-box" framework in which the characteristics of coils and inductive channels are represented by a small set of scattering parameters. The optimal transmit excitations are derived for maximum capacity, maximum delivered power, and SWIPT optimization objectives. We compute the rate-energy region and magnetic fields for a 2x2 MIMO SWIPT model by simulation.