volume | PIER Journals

Abstract

Dielectric or magnetic materials introduced in a wireless power transfer (WPT) system affect the properties of WPT. This paper quantitatively studies the coupling between the transmitting and receiving elements for a WPT system including either dielectric or magnetic materials. The transmitting and receiving elements are open spirals and solenoid coils which are usually used in WPT systems. The analysis method is the perturbation method which can calculate the total coupling coefficient k, the electric coupling component k_e and the magnetic coupling component k_m simultaneously. This paper gives quantitatively analyzed data on k_m and k_e to indicate how much k_m and k_e are affected by a dielectric or magnetic material introduced in a WPT system.

1. Tesla, N., Transmission of electrical energy without wire, Elect. World Eng., Mar. 5, 1904, Online Available: www.tfcbooks.com/tesla/.

2. Kurs, A., A. Karalis, R. Moffatt, J. D. Joannopoulos, P. Fisher, and M. Soljacic, "Wireless power transfer via strongly coupled magnetic resonances," Science, Vol. 317, 83-86, Jul., 2007.
doi:10.1126/science.1143254

3. Shonohara, N., Wireless Power Transfer via Radiowaves, ISTE Ltd and John Wiley & Sons, Inc, 2014.

4. Awai, I., "Magnetic resonant wireless power transfer," Nikkei Electronics, 2011.

5. Ohira, T., "Maximum available efficiency formulation based on a black-box model of linear twoport power transfer systems," IEICE Electronics Express, ELEX, Vol. 11, No. 13, 1-6, 2014.

6. Awai, I., Y. Zhang, T. Komori, and T. Ishizaki, "Coupling coefficient of spiral resonators used for wireless power transfer," 2010 Asia-Pacific Microwave Conference, 773-776, Dec. 2010.

7. Zhang, Y., T. Yoshikawa, and I. Awai, "Analysis of electric and magnetic coupling components for spiral resonators used in wireless power transfer," 2014 Asia-Pacific Microwave Conference, 1366-1368, Nov. 2014.

8. Awai, I. and T. Ishizaki, "Design of magnetic resonance type WPT systems based on filter theory," Electronics and Communications in Japan, Vol. 96, No. 10, 1-11, 2013.
doi:10.1002/ecj.11543

9. Hui, S. Y. R., "Magnetic resonance for wireless power transfer [A look back]," IEEE Power Electronics Magazine, Vol. 3, No. 1, 14-31, 2016.
doi:10.1109/MPEL.2015.2510441

10. Zhang, J., X. Yuan, C.Wang, and Y. He, "Comparative analysis of two-coil and three-coil structures for wireless power transfer," IEEE Transactions on Power Electronics, Vol. 32, No. 1, 341-352, 2017.
doi:10.1109/TPEL.2016.2526780

11. Tierney, B. B. and A. Grbic, "Design of self-matched planar loop resonators for wireless nonradiative power transfer," IEEE Transactions on Microwave Theory and Techniques, Vol. 62, No. 4, 909-919, 2014.
doi:10.1109/TMTT.2014.2303940

12. Awai, I., S. Iwamujra, H. Kubo, and A. Sanada, "Separation of coupling coefficient between resonators into electric and magnetic contributions," IEICE Trans. Electron, Vol. J88-C, No. 12, 1033-1039, 2005.

13. Hong, J.-S. and M. J. Lancaster, Microstrip Filters for RF/Microwave Applications, John Wiley & Sons, Inc., 2001.
doi:10.1002/0471221619

14. Awai, I. and Y. Zhang, "Coupling coefficient of resonators," IEICE Trans. Electron, Vol. J89-C, No. 12, 962-968, 2006.

15. Elnaggar, S. Y., R. J. Tervo, and S. M. Mattar, "Coupled mode theory applied to resonators in the presence of conductors," IEEE Transactions on Microwave Theory and Techniques, Vol. 63, No. 7, 2124-2132, 2015.
doi:10.1109/TMTT.2015.2432766

16. Awai, I., Y. Sawahara, and T. Ishizaki, "Choice of resonators for a WPT system in lossy materials," IEEE WPTC 2014, T-Fr3-4, May 2014.

Professor Yangjun Zhang

Mr. Tatsuya Yoshikawa

Dr. Takahiro Kitahara