volume | PIER Journals

Abstract

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.

1. Tesla, N., "Apparatus for transmitting electrical energy,", US patent number 1,119,732, 1914.
doi:10.1126/science.1143254

2. Kurs, A. K., A. Moffatt, R. Joannopoulos, J. D. Fisher, P., and M. Soljacic, "Wireless power transfer via strongly coupled magnetic resonances," Science, Vol. 317, No. 5834, 83-86, 2007.
doi:10.1109/TIE.2010.2046002

3. Sample, A. P., D. A. Meyer, and J. R. Smith, "Analysis, experimental results, and range adaptation of magnetically coupled resonators for wireless power transfer," IEEE Trans. Ind. Electron., Vol. 58, No. 2, 544-554, 2011.
doi:10.1587/elex.6.1421

4. Hirayama, H., T. Ozawa, Y. Hiraiwa, N. Kikuma, and K. Sakakibara, "A consideration of electromagnetic- resonant coupling mode in wireless power transmission," IEICE Elec. Exp., Vol. 6, No. 19, 1421-1425, 2009.

5. Sekine, D. and M. Taki, "Relationship between human exposure and resonance mode of wireless power transfer with magnetic resonance," IEICE Conf., B-4-8, 2012 (Japanese).
doi:10.1088/0031-9155/58/17/N241

6. Hirata, A., F. Ito, and I. Laakso, "Confirmation of quasi-static approximation in SAR evaluation for a wireless power transfer system," Phys. Med. Biol., Vol. 58, N241-N249, 2013.
doi:10.1109/TMTT.2013.2274053

7. Park, S., K. Wake, and S. Watanabe, "Incident electric field effect and numerical dosimetry for a wireless power transfer system using magnetically coupled resonances," IEEE Trans. Microw. Theory Tech., Vol. 61, No. 9, 3461-3469, 2013.
doi:10.5515/JKIEES.2015.15.3.129

8. Park, S., "Dosimetry for resonance-based wireless power transfer charging of electric vehicles," J. Electromagn. Eng. Sci., Vol. 15, No. 3, 129-133, 2015.

9. ICNIRP "Guidelines for limiting exposure to time-varying electric, magnetic, and electromagnetic fields (up to 300GHz)," Health Phys., Vol. 74, 494-522, 1998.

10. ICNIRP "Guidelines for limiting exposure to time-varying electric and magnetic fields (1Hz to 100 kHz)," Health Phys., Vol. 99, 818-836, 2010.

11. IEEE "Standard for safety levels with respect to human exposure to electromagnetic fields, 0– 3kHz," IEEE Standard, C95.6, 2002.

12. IEEE "Standard for safety levels with respect to human exposure to radiofrequency electromagnetic fields, 3 kHz to 300 GHz," IEEE Standard, C95.1, 2005.

13. Bleaney, B. I. and B. Bleaney, Electricity and Magnetism, 3rd Ed., Oxford Univ. Press, Oxford, 1976.

14. Montgomery, C. G., R. H. Dicke, and E. M. Purcell, Principles of Microwave Circuits, McGraw-Hill, New York, 1948.

15., Computer Simulation Technology, , Available online: www.cst.com (accessed on August 15, 2016).
doi:10.1088/0031-9155/49/1/001

16. Nagaoka, T., S. Watanabe, K. Sakurai, E. Kunieda, S. Watanabe, M. Taki, and Y. Yamanaka, "Development of realistic high-resolution whole-body voxel models of Japanese adult males and females of average height and weight, and application of models to radio-frequency electromagnetic field dosimetry," Phys. Med. Biol., Vol. 49, 1-15, 2004.

17. Gabriel, C. and S. Gabriel, "Compilation of the dielectric properties of body tissues at RF and microwave frequencies,", Brooks AFB, San Antonio, TX, USA, 2006.

18. FEKO — EM Simulation Software, Available online: www.feko.info (accessed on August 15, 2016).

Dr. Sang Wook Park