MODELING OF SHIELDING COMPOSITE MATERIALS AND STRUCTURES FOR MICROWAVE FREQUENCIES

Abstract

Composites containing conducting inclusions are required in many engineering applications, especially, for the design of microwave shielding enclosures to ensure electromagnetic compatibility and electromagnetic immunity. Herein, multilayer shielding structures are studied, with both absorbing and re∞ecting composite layers. In this paper, flber-fllled composites are considered. For modeling absorbing composites with low concentration of conducting cylindrical inclusions (below the percolation threshold), the Maxwell Garnett theory is used. For re∞ecting layers, when concentration of inclusions is close to or above the percolation threshold, the McLachlan formulation is used. Frequency dependencies for an efiective permittivity are approximated by the Debye curves using a curve-fltting procedure, in particular, a genetic algorithm.