The Shielding Effectiveness of Heterotypic Enclosures Embedded Dielectric Layers Based on the BLT Equation
Hao Jianhong1, Jiang Luhang1, Qian Siyang2
1. School of Electrical and Electronic Engineering North China Electric Power University Beijing 102206 China; 2. China Power Construction Engineering Consulting Co. Ltd Beijing 100120 China
Abstract：The outer shape and inner structure will affect the shielding effectiveness (SE) of metallic enclosures. By deriving the scattering parameter of the equivalent circuit at the discontinuous position of the heterotypic enclosure, the analytical models for the SE of an enclosure with convex structure and an enclosure with stepped structure excited by a plane wave are established based on the electromagnetic topology theory and the BLT equation. The effects of the position of the dielectric layer on the SE of the heterotypic enclosure are then analyzed. The analytical model can be used to calculate the SE at any point in the enclosure with arbitrarily positioned aperture by introducing the coefficients of the aperture position and the observation point position. The results show that dielectric layer can effectively suppress the resonance of the heterotypic enclosure, which improves the SE for frequencies near the resonances while less affecting the SE for frequencies far away from the resonances. The optimal layer position exists at different resonance points, thus the SE reaches the maximum value within the interval of the layer position. The analytical results are in good agreement with those of the full-wave simulation software CST, which validates the efficiency of the analytical models. Compared with the numerical methods, the analytical model has higher efficiency and requires less memory, which has guiding significance for the shielding design of heterotypic enclosures.
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2020, Vol. 35 
