Induced field and SAR in human body model due to wireless power transfer system with induction coupling

The present study investigates the SAR (specific absorption rate) and the induced electric field in an anatomically based model for the magnetic field from a wireless power transfer system. The waiting and charging conditions are considered. The transfer frequency considered herein is from 100 kHz and 150 kHz where a magneto-quasi-static approximation is valid. A two-step quasi-static method comprised of the method of moments and the scalar potential finite difference method is then used. First, the method of moments is used to calculate the magnetic field of wireless transfer system without the presence of the human body model. Then, the SAR and the electric field in the model are calculated by solving the scalar potential finite difference method. From computational results, the peak values of the SAR averaged over 10 g of tissue and the induced electric field for the transfer power of 5 W are substantially smaller than 2 W/kg and 18.9 V/m, the basic restrictions for those for general public, prescribed in the international guidelines/standard. The results indicate the induced electric field as a dominant factor when evaluating the compliance of the wireless power transfer system.