volume | PIER Journals

Abstract

This paper presents dosimetry of a high resonance wireless power transfer (HR-WPT) system when the transmitter and receiver are aligned and misaligned. An HR-WPT system with two resonant coils and two feeding loops, operating at 13.56 MHz is designed. The power transfer efficiency of the system, and the electric and magnetic fields are investigated using the method of moments. The power transfer efficiency in misalignment situations can be increased by matching the HR-WPT system. Dosimetry of the HR-WPT system is conducted at the optimum matching condition for alignment and misalignment, to achieve the best power transfer efficiency. The specific absorption rate (SAR) is computed using a two-step approach. In the first step, the magnetic fields generated by the HR-WPT system in the absence of a whole-body voxel human model are calculated using the method of moments. In the second step, the SAR in the human model is calculated using the impedance method, with the magnetic fields computed in the previous step regarded as the magnetic fields incident to the human body. Five exposure scenarios are set: one alignment condition and four misalignment conditions. The SAR computed for the alignment and misalignment cases in the matching condition are compared to each other. The compliance of the system is also investigated using the international safety guidelines. Finally, the maximum allowable powers to comply with the guideline are investigated for the five cases considered. The results show that the SARs observed in the misalignment case are higher than those in the alignment case. These results suggest that the misalignment situation should be considered in addition to alignment, when conducting dosimetry of the HR-WPT system.

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Dr. Sang Wook Park