An Efficient Method for Computing the Shielding Effectiveness of Arbitrary-Shape Multilayered Composite Enclosures

An efficient method is proposed to determine the shielding effectiveness of an arbitrary-shape multilayered composite enclosure. In this method, first, each layer of the enclosure is treated separately by applying appropriate boundary conditions to the interfaces between adjacent layers. The method of moments (MoM) is then used to solve the resultant surface integral equations (SIEs) for the unknown equivalent electric and magnetic current densities at the interfaces. Finally, these currents are utilized to determine the transmitted electric and magnetic fields into the enclosure, enabling one to compute the shielding properties of the enclosure. The main feature of the proposed method is its remarkable computational efficiency as compared with the conventional scheme where the layers and their respective interfaces are treated simultaneously. This is elucidated by deriving the MoM impedance matrix in a block-tridiagonal format. Using proper mathematical manipulations, it is shown that the inversion of the impedance matrix can be done much more efficiently than the standard matrix inversion codes. The validity and efficiency of the proposed method are demonstrated by comparing the simulation results of several case studies with those available in the literature or obtained using the SIE-MoM solver of a commercial code.