Research on the Shielding Effectiveness Analytical Algorithm of Enclosures with a Single Slanted Elliptical Aperture

An analytical model is proposed in this paper to rapidly and accurately calculate the shielding effectiveness of an enclosure with a single slanted elliptical aperture. The analytical model can not only predict the shielding effectiveness of any position in the enclosure when the aperture deviates from the center of the wall, but also analyze the shielding ability of the enclosure when the aperture shape is irregular. First, the oblique elliptical aperture is equivalent to two horizontal elliptical apertures through the principle of mirror image and magnetic current. Then the aperture impedance of the equivalent elliptical aperture is calculated by the iterative formula. Finally, the equivalent circuit method is used to solve the shielding effectiveness of the decomposed enclosures. According to the analytical relationship, the shielding effectiveness of an enclosure with a single slanted elliptical aperture can be obtained. Six sets of experiments were designed to validate the analytical model. The results of the model calculated by the software MATLAB are compared with the simulation results of the time domain transmission line matrix method (TLM) and the frequency domain finite element method (FEM) in the three-dimensional electromagnetic simulation software CST. The accuracy and efficiency of the model in this paper are verified. The model in this paper has reference significance for practical engineering applications and researchers' regular exploration.