Magnetic Shielding of a Thick Circular Conductive Disk Against a Coaxial Current Loop

The problem of evaluating the shielding effectiveness of a metallic circular disk with finite conductivity and finite thickness against a circular current loop coaxial with the disk is addressed. First the metallic disk is modeled through a new boundary condition which correctly takes into account the thickness of the disk and then the problem is reduced to only one set of dual integral equations which are solved in an exact form by expanding the spectral unknowns in a series of Bessel functions. The proposed formulation is compared with the one based on the Mitzner boundary conditions, showing its accuracy and the capability of reducing the computation time and with the one based on the thin-screen boundary conditions, showing that the latter can lead to erroneous results for sufficiently large thickness-to-skin-depth ratios.