Basic Analysis of Two-Coils Structure Based on Magnetically-Coupled Resonant Technology for SWIPT Application

The Magnetically-coupled resonant (MCR) technology is exploited in this paper to realize Synchronous wireless information and power transfer (SWIPT) function, which means that the power carriers also transmit information. The circuit structure of SWIPT system is analyzed and the existence of two optimal frequencies in power efficiency under small resistance circumstance is proved. The physical parameters having influences on the two optimal frequencies are discussed, such as the distance between coils, impedance characteristics of coils and loads. These results provide a way to increase the bandwidth of MCR technology, while maintaining high power efficiency to realize SWIPT function. Simulations and experimental results are presented to verify the feasibility of the proposed system and obtained theoretical expressions.