In this paper, an efficient wireless power transfer (WPT) system integrating with highly sub-wavelength metamaterials is proposed. The negative refractive index (NRI) and negative permeability (MNG) metamaterials for operation at radio frequencies are designed and applied to WPT system for improvement of power transfer efficiency. A dual-layer design which consists of a planar spiral on one side and a meander line touching with narrow metallic strips on the other side produces the properties of effective negative permittivity and permeability simultaneously, i.e., negative refractive index. In addition, the structure of double spirals produces a negative permeability. The cell size of the NRI and MNG metamaterials is about 253 times smaller than the operation wavelength. By integrating one, two, three or four metamaterial slabs between the two coupling copper rings, the transfer efficiency is improved significantly. The measured results show that the contribution of high transfer efficiency is due to the property of negative permeability which can make the WPT system work in the mechanism of magnetic resonance.
"Experimental Study of Efficient Wireless Power Transfer System Integrating with Highly Sub-Wavelength Metamaterials," Progress In Electromagnetics Research,
Vol. 141, 769-784, 2013. doi:10.2528/PIER13061711
1. Tesla, N., "The transmission of electrical energy without wires as a means for furthering peace," Electrical World and Engineer, 21-24, January 7, 1905.
2. Kurs, A., A. Karalis, R. Moffatt, J. D. Joannopoulos, P. Fisher, and M. Soljacic, "Wireless power transfer via strongly coupled magnetic resonance," Science, Vol. 317, 83-86, Jul. 6, 2007. doi:10.1126/science.1143254
3. Huang, D., Y. Urzhumov, D. R. Smith, K. H. Teo, and J. Zhang, "Magnetic superlens-enhanced inductive coupling for wireless power transfer," Journal of Applied Physics, Vol. 111, 064902, 2012. doi:10.1063/1.3692757
4. Cannon, B. L., J. F. Hoburg, D. D. Stancil, and S. C. Goldestein, "Magnetic resonant coupling as a potential means for wireless power transfer to multiple small receivers," IEEE Transactions on Power Electronics, Vol. 24, No. 7, 1819-1825, Jul. 2009. doi:10.1109/TPEL.2009.2017195
5. Choi, J. and C. Seo, "High-efficiency wireless energy transmission using magnetic resonance based on metamaterial with relative permeability equal to -1," Progress In Electromagnetics Research, Vol. 106, 33-47, 2010. doi:10.2528/PIER10050609
6. Wang, B., K. H. Teo, T. Nishino, W. Yerazunis, J. Barnwell, and J. Zhang, "Experiments on wireless power transfer with metamaterials," Appl. Phys. Lett., Vol. 98, 254101, 2011. doi:10.1063/1.3601927
7. Urzhumov, Y. and D. R. Smith, "Metamaterial-enhanced coupling between magnetic dipoles for efficient wireless power transfer," Phys. Rev. B, Vol. 83, 205114, 2011. doi:10.1103/PhysRevB.83.205114
8. Li, L., Y. C. Fan, S. X. Yu, C. Zhu, and C. H. Liang, "Design, fabrication and measurement of highly sub-wavelength double negative metamaterials at HF frequencies," Journal of Applied Physics, Vol. 113, 213712, 2013. doi:10.1063/1.4809769
9. Pendry, J. B., "Extremely low frequency plasmons in metallic microstructures," Phys. Rev. Lett., Vol. 76, 4773-4776, 1996. doi:10.1103/PhysRevLett.76.4773
10. Shelby, R. A., D. R. Smith, and S. Schultz, "Experimental verification of a negative index of refraction," Science, Vol. 292, 77-79, 2001. doi:10.1126/science.1058847
11. Smith, D. R., W. J. Padilla, and D. C. Vier, "Composite medium with simultaneously negative permeability and permittivity," Phys. Rev. Lett., Vol. 84, No. 18, 4184-4187, 2000. doi:10.1103/PhysRevLett.84.4184
12. Chen, W. C., C. M. Bingham, K. M. Mak, N. W. Caira, and W. J. Padilla, "Extremly sub-wavelength planar magnetic metamaterials," Phys. Rev. B, Vol. 85, 201104, 2012. doi:10.1103/PhysRevB.85.201104
13. Smith, D. R., D. C. Vier, Th. Koschny, and C. M. Soukoulis, "Electromagnetic parameter retrieval from inhomogeneous metamaterials," Phys. Rev. E, Vol. 71, 036617, 2005. doi:10.1103/PhysRevE.71.036617