This article focuses on the low-frequency magnetic shielding of double-layer conducting plates with periodic circular apertures. The shielding effectiveness (SE) is measured as the insertion loss of the plates when they are placed between a pair of coaxial loops, one for magnetic field emission and the other for receiving. Our experimental results show that the SE sharply increases with the layer-to-layer spacing increasing from zero to the aperture diameter. For aluminum plates with 1 mm thickness, 20 mm unit cell and 10 mm aperture diameter, the enhancement is approximately 10 dB and 20 dB for 3 mm and 9 mm spacing, respectively. In addition, the effect of the lateral deviation on the SE is evident only if the spacing is smaller than the aperture diameter.
2. Lee, S., et al., "Low leakage electromagnetic field level and high efficiency using a novel hybrid loop-array design for wireless high power transfer system," IEEE Trans. Ind. Electron., Vol. 66, No. 6, 4356-4367, Jun. 2019.
3. Zhou, Y., L. Zhang, S. Xiu, and W. Hao, "Design and analysis of platform shielding for wireless charging tram," IEEE Access, Vol. 7, 129443-129451, Sep. 2019.
4. Zhang, J., T. Lu, W. Zhang, X. Bian, and X. Cui, "Characteristics and in uence factors of radiated disturbance induced by IGBT switching," IEEE Trans. Power Electron., Vol. 34, No. 12, 11833-11842, Dec. 2019.
5. Ma, D., et al., "Study of shielding ratio of cylindrical ferrite enclosure withgaps and holes," IEEE Sens. J., Vol. 19, No. 15, 6085-6092, Aug. 2019.
6. Giaccone, L., V. Cirimele, and A. Canova, "Mitigation solutions for the magnetic field produced by MFDC spot welding guns," IEEE Trans. Electromagn. Compat., Vol. 62, No. 1, 83-92, Feb. 2020.
7. Kellogg, J., "Navigating the selection of magnetic resonance imaging shielding systems," IEEE Trans. Electromagn. Compat., Vol. 3, No. 1, 43-46, Mar. 2021.
8. Salvador, K., D. Harmel, L. Oliveira, S. Cabral, and H. Almaguer, "Study of the effectiveness of magnetic shielding for compact power transformers used on mobile applications," IEEE Latin Am. Trans., Vol. 18, No. 6, 1034-1040, Jun. 2020.
9. Frikha, A., M. Bensetti, F. Duval, N. Benjelloun, F. Lafon, and L. Pichon, "A new methodology to predict the magnetic shielding effectiveness of enclosures at low frequency in the near field," IEEE Trans. Magn., Vol. 51, No. 3, 1-4, Mar. 2015.
10. Lovat, G., P. Burghignoli, R. Araneo, E. Stracqualursi, and S. Celozzi, "Closed-form LF magnetic shielding effectiveness of thin planar screens in coplanar loops configuration," IEEE Trans. Electromagn. Compat., Vol. 63, No. 2, 631-635, Apr. 2021.
11. Jiao, C., et al., "Low-frequency magnetic shielding of planar shields: A unified wave impedance formula for the transmission line analogy," IEEE Trans. Electromagn. Compat., Vol. 63, No. 4, 1046-1057, Feb. 17, 2021.
12. Zhang, Z., X. Yang, C. Jiao, Y. Yang, and J. Wang, "Analytical model for low-frequency magnetic field penetration through a circular aperture on a perfect electric conductor plate," IEEE Trans. Electromagn. Compat., Vol. 63, No. 5, 1599-1604, Apr. 6, 2021.
13. Qin, D. and C. Jiao, "Low-frequency magnetic shielding of planar screens: Effects of loop radius and loop-to-loop distance," IEEE Trans. Electromagn. Compat., Vol. 64, No. 2, 367-377, 2022.
14. Park, H. H., "Analytic magnetic shielding effectiveness of multiple long slots on a metal plate using rectangular loops," IEEE Trans. Electromagn. Compat., Vol. 62, No. 5, 1971-1979, Oct. 2020.
15. Bai, W., F. Ning, X. Yang, C. Jiao, and L. Chen, "Low frequency magnetic shielding effectiveness of a conducting plate with periodic apertures," IEEE Trans. Electromagn. Compat., Vol. 63, No. 1, 30-37, Feb. 2021.
16. Criel, S., L. Martens, and D. De Zutter, "Theoretical and experimental near-field characterization of perforated shields," IEEE Trans. Electromagn. Compat., Vol. 36, No. 3, 161-168, Aug. 1994.
17. Araneo, R., G. Lovat, and S. Celozzi, "Shielding effectiveness of periodic screens against finite high-impedance near-field sources," IEEE Trans. Electromagn. Compat., Vol. 53, No. 3, 706-716, Aug. 2011.
18. Sarto, M. S., S. Greco, and A. Tamburrano, "Shielding effectiveness of protective metallic wire meshes: EM modeling and validation," IEEE Trans. Electromagn. Compat., Vol. 56, No. 3, 615-621, Jun. 2014.
19. Hyun, S., I. Jung, I. Hong, C. Jung, E. Kim, and J. Yook, "Modified sheet inductance of wire mesh using effective wire spacing," IEEE Trans. Electromagn. Compat., Vol. 58, No. 3, 911-914, Jun. 2016.
20. Naranjo-Villamil, S., C. Guiffaut, J. Gazave, and A. Reineix, "Lightning-induced magnetic fields inside grid-like shields: An improved formula complemented by a polynomial chaos expansion," IEEE Trans. Electromagn. Compat., Vol. 63, No. 2, 558-570, Apr. 2021.
21. Bai, W., A. Guo, T. Li, R. Cheng, and C. Jiao, "A multi-stage model for the electromagnetic shielding effectiveness prediction of an infinite conductor plane with periodic apertures," IEEE Access, Vol. 7, 61896-61903, 2019.
22. Sun, X., B. Wei, Y. Li, and J. Yang, "A new model for analysis of the shielding effectiveness of multilayer infinite metal meshes in a wide frequency range," IEEE Trans. Electromagn. Compat., Vol. 64, No. 1, 102-110, Sep. 1, 2021.
23. Andrieu, G., et al., "Homogenization of composite panels from a near-field magnetic shielding effectiveness measurement," IEEE Trans. Electromagn. Compat., Vol. 54, No. 3, 700-703, Jun. 2012.
24. Yang, X., Z. Zhang, F. Ning, C. Jiao, and L. Chen, "Shielding effectiveness analysis of the conducting spherical shell with a circular aperture against low-frequency magnetic fields," IEEE Access, Vol. 8, 79844-79850, 2020.
25. MWS. Framingham, MA, , USA, 2015. CST Computer Simulation Technology, 2011. [Online]. Available: http://www.cst.com/Content/Products/MWS/Overview.aspx.