SAR in a simplified human model due to wireless power transfer with induction coupling

This study investigates the SAR (specific absorption rate) in a homogeneous cubic model simulating a human trunk due to the magnetic field of wireless power transfer. The waiting and charging conditions are considered. The transfer frequency considered herein is in the 100 kHz band where a 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 in free space. Then, the SAR in the cubic model is calculated by solving the scalar potential finite difference method. From computational results, the peak value of SAR averaged over 10 g of tissue is 48 μW/kg in the waiting condition for the transfer power of 1 W, which is somewhat larger than 43 μW/kg for the charging mode. These values are substantially smaller than 2 W/kg, the basic restriction for general public, prescribed in the international guidelines/standard.