Mechanism of two resonant modes for highly resonant wireless power transfer and specific absorption rate

In this work, the dosimetry for two resonant modes of a highly resonant wireless power transfer (HR-WPT) system is investigated, and the results are compared. The physical mechanism of the two resonant modes, which occur when the two transmitting and receiving resonators are extremely close to one another, is presented with the simulated results and the equivalent circuit models for the HR-WPT system. The difference between the two resonant modes for the specific absorption rate induced in the head model is discussed by comparing the electromagnetic fields for each mode. Furthermore, the dosimetry for the four-coil HR-WPT system is also investigated under the conditions of a single resonant mode and two resonant modes. The specific absorption rates (SARs) are calculated with head-size and body-size simplified human models at various distances from the WPT system and in each mode. The electric and magnetic fields of the odd mode show stronger distribution than those of the even mode in the area near to the WPT system, while the opposite results are found in the area farther away. © 2016 Electromagnetics Academy. All rights reserved.