The configuration of an infinite planar conductive shield is examined when it is excited by an electromagnetic near field generated by a coil current source as that of a wireless power transfer (WPT) system. The analytical expressions of the electromagnetic field based on the transmission theory of shielding are given for different frequencies and different incidence angles of the near field generated by the coil current, assuming the conductive planar shield placed in the close proximity of the coil. The obtained results are discussed and compared with other traditional analytical and numerical solutions.
1. Schelkunoff, S. A., Electromagnetic Waves, Van Nostrand Company, New York, 1943.
2. Moser, J. R., "Low-frequency shielding of a circular loop electromagnetic field source," IEEE Trans. Electromag. Compat., Vol. 9, No. 1, 6-18, Mar. 1967. doi:10.1109/TEMC.1967.4307447
3. Moser, J. R., "Low-frequency low-impedance electromagnetic shielding," IEEE Trans. Electromag. Compat., Vol. 30, No. 3, 202-210, Aug. 1988. doi:10.1109/15.3298
4. Bannister, P. R., "New theoretical expressions for predicting shielding effectiveness for the plane shield case," IEEE Trans. Electromag. Compat., Vol. 10, No. 1, 2-7, Mar. 1968. doi:10.1109/TEMC.1968.302900
5. Bannister, P. R., "Further notes for predicting shielding effectiveness for the plane shield case," IEEE Trans. Electromag. Compat., Vol. 11, No. 2, 50-53, May 1969. doi:10.1109/TEMC.1969.303010
6. Whitehouse, A. C. D., "Screening: New wave impedance for the transmission-line analogy," Proc. of IEEE, Vol. 116, No. 7, 1159-1164, Jul. 1969.
7. Wait, J. R., "Image theory of a quasistatic magnetic dipole over a dissipative half-space," Electronics Letters, Vol. 5, No. 13, 281-282, Jun. 1969. doi:10.1049/el:19690214
8. Nishikata, A. and A. Sugiura, "Analysis for electromagnetic leakage through a plane shield with an arbitrarily-oriented dipole source," IEEE Trans. Electromag. Compat., Vol. 34, No. 3, 284-291, Aug. 1992. doi:10.1109/15.155843
9. Schultz, R. B., V. C. Plantz, and D. E. Brush, "Shielding Theory and Practice," IEEE Trans. Electromag. Compat., Vol. 30, No. 3, 187-201, Aug. 1988. doi:10.1109/15.3297
10. Olsen, R. G., "Some observations about shielding extremely low-frequency magnetic fields by finite width shields," IEEE Trans. Electromagn. Compat., Vol. 38, No. 3, 460-468, Aug. 1996. doi:10.1109/15.536076
11. Frix, W. M. and G. G. Karaday, "A circuital approach to estimate the magnetic field reduction of nonferrous metal shields," IEEE Trans. Electromag. Compat., Vol. 39, No. 1, 24-32, Feb. 1997. doi:10.1109/15.554692
12. Du, Y., T. C. Cheng, and A. S. Farag, "Principles of power-frequency magnetic field shielding with flat sheets in a source of long conductors," IEEE Trans. Electromag. Compat., Vol. 38, No. 3, 450-459, Aug. 1996. doi:10.1109/15.536075
13. 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, No. 5834, 83-86, Jul. 2007. doi:10.1126/science.1143254
14. Kim, J., J. Kim, S. Kong, H. Kim, I.-S. Suh, N. P. Suh, D.-H. Cho, J. Kim, and S. Ahn, "Coil design and shielding methods for a magnetic resonant Wireless Power Transfer system," Proc. IEEE, Vol. 101, No. 6, 1332-1341, Jun. 2013. doi:10.1109/JPROC.2013.2247551
15. Cruciani, S. and M. Feliziani, "Mitigation of the magnetic field generated by a wireless power transfer (WPT) system without reducing the WPT efficiency," EMC Europe — Int. Symposium on EMC, Bruges, Belgium, Sept. 2–6, 2013.
16. Campi, T., S. Cruciani, and M. Feliziani, "Magnetic shielding of wireless power transfer systems," EMC’14,/Tokyo, Proc of 2014 Int. Symp. Electromag. Compat., Tokyo, Japan, May 12–16, 2014.
17. Babic, S. I., J. Martinez, C. Akyel, and B. Babic, "Mutual inductance calculation between misalignment coils for wireless power transfer of energy," Progress In Electromagnetics Research, Vol. 38, 91-102, 2014. doi:10.2528/PIERM14073007
18. Poon, A. S. Y., "A general solution to wireless power transfer between two circular loop," Progress In Electromagnetics Research, Vol. 148, 171-182, 2014. doi:10.2528/PIER14071201
19. Campi, T., S. Cruciani, V. De Santis, and M. Feliziani, "EMF safety and thermal aspects in a pacemaker equipped with a wireless power transfer system working at low frequency," EEE Trans. Microw. Th. Techn., Vol. 64, No. 2, 375-382, Feb. 2016.
20. Campi, T., S. Cruciani, V. De Santis, F. Palandrani, A. Hirata, and M. Feliziani, "Wireless power transfer charging system for AIMDs and pacemakers," IEEE Trans. Microw. Th. Techn., Vol. 64, No. 2, 633-642, Feb. 2016. doi:10.1109/TMTT.2015.2511011
21. Simpson, J. C., J. E. Lane, C. D. Immer, and R. C. Youngquist, "Simple analytic expressions for the magnetic field of a circular current loop," NASA Technical Report 2001, NASA/TM-2013-217919, Available online: http://ntrs.nasa.gov/search.jsp?R=20140002333.
22. Griffith, J. M. and G. W. Pan, "Time harmonic fields produced by circular current loops," IEEE Trans. Magnetics, Vol. 47, No. 8, 2029-2033, Aug. 2011. doi:10.1109/TMAG.2011.2132731
23. Balanis, C. A., Antenna Theory: Analysis and Design, 3rd Ed., J. Wiley, NY, 2005.
24. Celozzi, S., R. Araneo, and G. Lovat, Electromagnetic Shielding, J. Wiley, Wiley Interscience, Hoboken, NJ, 2008. doi:10.1002/9780470268483
25. Feliziani, M., F. Maradei, and G. Tribellini, "Field analysis of penetrable conductive shields by the Finite-Difference Time-Domain Method with Impedance Network Boundary Conditions (INBC’s)," IEEE Trans. Electromag. Compat., Vol. 41, No. 4, 307-319, Nov. 1999. doi:10.1109/15.809801
26. Buccella, C., M. Feliziani, F. Maradei, and G. Manzi, "Magnetic field computation in a physically large domain with thin metallic shields," IEEE Trans. Magnetics, Vol. 41, No. 5, 1708-1711, May 2005. doi:10.1109/TMAG.2005.846059
27. Feliziani, M., "Subcell FDTD modeling of field penetration through lossy shields," IEEE Trans. Electromag. Compat., Vol. 54, 299-307, 2012. doi:10.1109/TEMC.2011.2160982