Analysis of Shielding Effectiveness of Metallic Rectangular Enclosures Using Efficient Integral Equations
The paper proposes an efficient modeling technique for electromagnetic analysis of a rectangular metallic enclosure with multiple apertures, using the surface equivalent principle and frequency-domain integral equations. The surface equivalence principle is used to replace the apertures by a prefect electrically conducting surfaces while introducing appropriate magnetic current densities on both sides of it with opposite sign. As a result, the problem is reduced to two independent regions. The first region is outside the enclosure (exterior problem) where the free space Green’s function with the aid of image theory can be used to obtain the total fields in it. The second region is the interior of the enclosure (interior problem) that a closed-form expression for its dyadic Green’s function is available. Finally the governing frequency-domain magnetic field integral equation for the structure is derived by enforcing the continuity of the tangential magnetic field at the apertures. To solve the resulting integral equations, method of moments is used. The validity of the proposed method is confirmed by comparing the simulation results of several case studies with those obtained using the commercial MWS-CST finite integration code.