Shielding of an Imperfect Metallic Thin Circular Disk: Exact and Low-Frequency Analytical Solution

Abstract

The problem of evaluating the shielding effectiveness of a thin metallic circular disk with finite conductivity against an axially symmetric vertical magnetic dipole is addressed. First, the thin metallic disk is modeled through an appropriate boundary condition, and then, as for the perfectly conducting counterpart, the problem is reduced to a set of dual integral equations which are solved in an exact form through the application of the Galerkin method in the Hankel transform domain. A second-kind Fredholm infinite matrix-operator equation is obtained by selecting a suitable set of basis functions. A low-frequency solution is finally extracted in a closed form. Through a comparison with results obtained from a full-wave commercial software, it is shown that such a simple approximate solution is accurate up to the frequency where the surface-impedance model of the thin disk is valid.

Low-frequency Magnetic Shielding of a Cavity Formed by Two Imperfectly Conducting Sheets: Effect of Sheet-to-sheet Distance and Comparison with the Single-sheet Configuration

“…Beyond this range, the finite element method (FEM) results are affected by the edge effect, since the sheet has finite size (1.2 m in radius) in the FEM model. Similar phenomena have been observed in [15,22].…”

“…For lower frequencies, the SE usually is the same as that at 10 Hz. For higher frequencies, the SE of the metallic sheet is very high so that the sheet can be considered as a perfectly electric conductor, and the only field penetration path is usually the apertures/seams on the sheet [19][20][21] or the edge effect for sheets with finite size [15,22].…”

Electromagnetic Response of Clustered Charged Particles

“…μ 1 μ r μ 0 and ε 1 ε r ε 0 are the permeability and permittivity of the particle, respectively, where μ r and ε r are the relative permeability and relative permittivity, respectively. We begin with the Mie scattering theory, by which the problem of plane waves scattered by a spherical particle can be rigorously solved through matching the boundary conditions (Kong, 1986;Bohren and Huffman, 1998;Mishchenko et al, 2002;Lovat et al, 2020). The field outside the particle can be expressed as the superposition of the incident field and the scattered field,…”

A Dual Integral Equation Approach for Evaluating the Shielding of Thick Circular Disks against a Coaxial Loop

“…On the other hand, the screening of a finite source (e.g., an electric or a magnetic dipole) by means of an infinite planar conductive shield is well-documented in both the frequency [18][19][20] and time [21,22] domains. Recently, the shielding of a thin conductive disk in the presence of an ideal vertical magnetic dipole has been studied in details [23]; however, the main assumption in [23] is that the disk thickness has to be smaller than the skin depth. Such an assumption introduces an upper limit in terms of frequency, and makes the formulation essentially into a low-frequency analysis.…”