THE APPLICATION OF ABSORPTION AND SCATTERING COEFFICIENTS FOR CONCENTRIC SPHERES TO THE PROBLEM OF EMI-FREE ENCLOSURES,
Abstract
With the purpose of increasing the information about the lower frequency shielding effectiveness of closed structures composed of various arbitrary materials, an idealized problem is considered of the scattering and absorption of a plane electromagnetic wave impinging on a spherical shell. The region between the outer and inner radius of the sphere contains an arbitrary material; the other two regions are free space. The absorption and scattering coefficients for the incident plane wave are expressed as an infinite sum of spherical waves, using spherical Bessel functions. The coefficients are calculated numerically and shown for a large range of complex material parameters and frequencies from 100 kc to 1000 mc. Equations were programmed in FORTRAN, and numerical calculations accomplished on the IBM 1620 computer. Combinations of complex material properties of permeability, permittivity and conductivity were sought which gave large, broadband absorption coefficients. Several promising compositions have resulted, and are presented. The effects of varying the individual parameters are also discussed. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 29, 1963
- Accession Number
- AD0424933
Entities
People
- H. A. Lasitter
- J. Roberts
- R. A. Eldred
Organizations
- Naval Facilities Engineering Service Center