volume | PIER Journals

Abstract

An analytical formulation has been developed to evaluate the shielding effectiveness (SE) of two coplanar rectangular metallic enclosures with acircular aperture excitedby an internal electric dipole source. The formulation consists of three parts: First, the near-field electromagnetic interference (EMI) of the electromagnetic leakage from the aperture is represented by the electric dipole in one enclosure. Then, the aperture equivalent magnetic and electric dipole moments are calculated according to the Bethe's small aperture coupling theory. Finally, the electric field of the other enclosure is derived by using the equivalent magnetic dipole field, equivalent electric dipole field and the corresponding enclosure's Green's functions in the two fields. In this formulation, the electric field of the enclosure can be expressed as a function of the observation point, the aperture's center point, source point, shape of the aperture and the enclosure's conductivity. The formulation then is employed to analyze the effect of the above factors on the SE. The analytical results have been successfully compared with the full-wave simulation software Computer Simulation Technology (CST) from 0.3~2.4 GHz.

1. Shim, J., D. G. Kam, J. H. Kwon, and J. Kim, "Circuital modeling and measurement of shielding effectiveness against oblique incident plane wave on apertures in multiple sides of rectangular enclosure," IEEE Trans. Electromagn. Compat., Vol. 52, No. 3, 566-577, 2010.
doi:10.1109/TEMC.2009.2039483

2. Hao, J.-H., P.-H. Qi, J.-Q. Fan, and Y.-Q. Guo, "Analysis of shielding effectiveness of enclosures with apertures and inner windows with TLM," Progress In Electromagnetic Research M, Vol. 32, 73-82, 2013.
doi:10.2528/PIERM13060312

3. Jiao, C.-Q. and H.-Z. Zhu, "Resonance suppression and electromagnetic shielding effectiveness improvement of an apertured rectangular cavity by using wall losses," Chin. Phys. B, Vol. 22, No. 8, 1-6, 2013.
doi:10.1088/1674-1056/22/8/084101

4. Song, H., D.-F. Zhou, D.-T. Hou, T. Hu, and J.-Y. Lin, "Hybrid algorithm for slot coupling of double layer shielding cavity," High Power Laser and Particle Beams, Vol. 20, No. 11, 1892-1898, 2008.

5. Hao, C. and D.-H. Li, "Shielding effectiveness of double-deck cavity with apertures," Chinese Journal of Radio Science, Vol. 29, No. 1, 114-121, 2014.

6. Luo, J.-W., P.-A. Du, D. Ren, and P. Xiao, "BLT equation-based approach for calculating shielding effectiveness of double layer rectangular enclosures with apertures," High Power Laser and Particle Beams, Vol. 27, No. 11, 1-6, 2015.

7. Liu, Q.-F., W.-Y. Yin, M.-F. Xue, J.-F. Mao, and Q.-H. Liu, "Shielding characterization of metallic enclosures with multiple slots and a thin-wire antenna loaded: multiple oblique EMP incidences with arbitrary polarizations," IEEE Trans. Electromagn. Compat., Vol. 51, No. 2, 284-292, 2009.
doi:10.1109/TEMC.2008.2011891

8. Liu, Q.-F., W.-Y. Yin, J.-F. Mao, and Z.-Z. Chen, "Accurate characterization of shielding effectiveness of metallic enclosures with thin wires and thin slots," IEEE Trans. Electromagn. Compat., Vol. 51, No. 2, 293-300, 2009.
doi:10.1109/TEMC.2008.927942

9. Shi, Z. and P.-A. Du, "Numerical simulation of near field shielding properties for aperture arrays based on FEM," Chin. J. Electron., Vol. 37, No. 3, 634-639, 2009.

10. Khorrami, M. A., P. Dehkhoda, R. M. Mazandaran, and S. H. H. Sadeghi, "Fast shielding effectiveness calculation of metallic enclosures with apertures using a multiresolution method of moments technique," IEEE Trans. Electromagn. Compat., Vol. 52, No. 1, 230-235, 2010.
doi:10.1109/TEMC.2009.2034644

11. Dehkhoda, P., A. Tavakoli, and M. Azadifar, "Shielding effectiveness of an enclosure with finite wall thickness and perforated opposing walls at oblique incidence and arbitrary polarization by GMMoM," IEEE Trans. Electromagn. Compat., Vol. 54, No. 4, 792-805, 2012.
doi:10.1109/TEMC.2012.2188855

12. Nie, B.-L., P.-A. Du, Y.-T. Yu, and Z. Shi, "Study of the shielding properties of enclosures with apertures at higher frequencies using the transmission-line modeling method," IEEE Trans. Electromagn. Compat., Vol. 53, No. 1, 73-81, 2011.
doi:10.1109/TEMC.2010.2047398

13. Bethe, H. A., "Theory of diffraction by small apertures," Physical Review Second Series, Vol. 66, 163-182, 1944.

14. Rao, Y.-P., H. Song, and D.-F. Zhou, "Fast estimation of shielding efficiency of cavity with thin slots," High Power Laser and Particle Beams, Vol. 20, No. 8, 1327-1332, 2008.

15. Li, Y. Y. and C. Q. Jiao, "Analytical formulation for electromagnetic leakage from an apertured rectangular cavity," PIERS Proceedings, 257-261, Guangzhou, China, Aug. 25-28, 2014.

16. Liu, E.-B., P.-A. Du, and B.-L. Nie, "An extended analytical formulation for fast prediction of shielding effectiveness of an enclosure at different observation points with an off-axis aperture," IEEE Trans. Electromagn. Compat., Vol. 56, No. 3, 589-598, 2014.
doi:10.1109/TEMC.2013.2289742

17. Luo, J.-W., P.-A. Du, D. Ren, and B.-L. Nie, "A BLT equation-based approach for calculating the shielding effectiveness of enclosures with apertures," Acta Phys. Sin., Vol. 64, No. 1, 1-8, 2015.

18. Boutar, A., A. Reineix, C. Guiffaut, and G. Andrieu, "An efficient analytical method for electromagnetic field to transmission line coupling into a rectangular enclosure excited by an internal source," IEEE Trans. Electromagn. Compat., Vol. 57, No. 3, 565-573, 2015.
doi:10.1109/TEMC.2014.2386913

19. Frederick, M. T., L. Michel, et al. EMC Analysis Methods and Computational Models, 1st Ed., Wiley Interscience, 1996.

Dr. Jian-Hong Hao

Dr. Lu-Hang Jiang

Dr. Yan-Fei Gong

Dr. Jie-Qing Fan