Electromagnetic shields are designed to optimize the performance for shielding effectiveness and reflectivity. Multilayered laminates of different materials are developed to achieve excellent results in terms of not only in shielding effectiveness but also for reflectivity. In this paper, a three layered laminate is considered for estimation of the required parameters in the X-band frequency range. A sandwich of conductive polymer between a conductor and microwave absorber yields very good performance. Several investigations were carried out for the estimation of shielding effectiveness and reflectivity of the three layered laminate structure at different thickness of each layer and for a combination of different materials.
1. Kodali, V. P., "Engineering Electromagnetic Compatibility, Principles, Measurements and Technologies," S Chand and Company Ltd, 2000.
2. Schulz, R. B., et al., "Shielding theory and practice," IEEE Transactions on Electromagnetic Compatibility, Vol. 30, No. 3, 187-201, Aug. 1988. doi:10.1109/15.3297
3. Jayasree, P. V. Y., et al., "Shielding effectiveness of laminated shields," Radio Engineering, Vol. 17, No. 4, Dec. 2008.
4. Meshram, M. R., N. K. Agrawal, B. Sinha, and P. S. Misra, "Transmission line modeling (TLM) for evaluation of absorption in ferrite based multi layer microwave absorber," TENCON 2003, Conference on Convergent Technologies for the Asia-Pacific Region, 626-629, 2003. doi:10.1109/TENCON.2003.1273246
5. Feng, Y., et al., "Microwave absorption properties of the carbonyl iron/EPDM radar absorbing materials," Journal of Wuhan University of Technology | Mater. Sci. Ed., Vol. 2, 266-270, Jun. 2007.
6. Praveen, S., et al., "Microwave absorption studies of Ca-NiTi hexaferrite composites in X-band," Materials Science and Engineering, Vol. B78, 70-74, 2000. doi:10.1109/20.801111
7. Cho, H.-S. and S.-S. Kim, "M-Hexa ferrites with planar magnetic anisotropy and their application to high-frequency microwave absorbers ," IEEE Transactions on Magnetics, Vol. 35, No. 5, 3151-3153, Sep. 1999. doi:10.1109/20.486547
8. Kim, D. Y., et al., "Dependence of microwave absorbing property on ferrite volume fraction in MnZn ferrite-rubber composites ," IEEE Transactions on Magnetics, Vol. 32, No. 2, 555-558, Mar. 1996.
9. Zhang, B., et al., "Microwave-absorbing properties of deaggregated °ake-shaped carbonyl-iron particle composites at 2-18 GHz," IEEE Transactions on Magnetics, Vol. 42, No. 7, 1178-1781, Jul. 2006. doi:10.1007/s10853-006-0921-y
10. Singh, P., et al., "Dielectric constant, magnetic permeability and microwave absorption studies of hot-pressed Ba-CoTi hexaferrite composites in X-band," Journal of Materials Science, Vol. 41, No. 21, 7190-7196, 2006. doi:10.1007/BF02706238
12. Verma, A., et al., "Microwave studies on strontium ferrite based absorbers," Journal of Electroceramics, Vol. 8, 203-208, 2002.
13. Jayasree, P. V. Y., et al., "Shielding effectiveness of conductive polymers against EM fields-a case study," IE(I) Journal --- ET, Vol. 90, Jul. 2009.
14. Naishadham, K. and P. K. Kadaba, "Measurement of the microwave conductivity of a polymeric material with potential applications in absorbers and shielding," IEEE Transactions on Microwave Theory Technol., Vol. 39, 1158-1164, Jul. 1991.
15. Naarman, H., "Synthesis of new conductive electronic polymers," Proceedings of International Congress Synthetic Metals, Kyoto, Japan, Jun. 1986. doi:10.1088/0022-3719/17/21/009
16. Ehinger, K., S. Summerfield, W. Bauhofer, and S. Roth, "DC and microwave conductivity of iodine-doped polyacetylene," Journal of Physics C: Solid State Physics, Vol. 17, No. 21, 3753-3762, 1984.
17. Jarva, W., "Shielding tests for cables and small enclosures in the 1-to 10-GHz range ," IEEE Transactions on Electromagnetic Compatibility, Vol. EMC-12, Feb. 1970.
18. Konefal, T., J. F. Dawson, and A. C. Marvin, Improved aperture model for shielding prediction, IEEE International Symposium on Electromagnetic Compatibility, 2003.