Cooperative transmitter structure for improving efficiency in wireless power transfer

Wireless power transfer (WPT) is widely used in portable devices with the advantage of flexibility and conveniences. This paper aims to design a cube transmitter structure, which generates a spatially focused magnetic field providing effective power transfer. The phase shift in multiple coils has been optimized for maximum power transfer efficiency and free positioning in the charging spatial domain. The performance of out-phase multiple coil cube (OPMC) antenna has been compared to that of in-phase multiple coil cube (IPMC) transmitter and traditional single coil. Simulation results show that the OPMC is better and provides higher efficiency wherever the receiver is located inside the cubical region above the cube base.