Dyson equation for electromagnetic scattering of heterogeneous media with spatially disordered particles: properties of the effective medium

[摘要] In this paper, we consider the coherent component of the electromagnetic wave field inside random media. The subject of our interest concerns a random medium, consisting of a statistical ensemble of different scattering species and artificial material structures developed on base of dielectric or metallic resonant or non-resonant particles. The starting point of our theory is the multiple scattering theory, the averaged electric field satisfies a Dyson equation with a mass operator related to the effective dielectric permittivity of the homogenized structure. Quantum multiple scattering theory has been transposed into this electromagnetic case. We give a formal solution for the mass operator by introducing the T-matrix formalism. We show that the T-matrix satisfies a Lippman-Schwinger equation. Then, we introduce the Quasi-Crystalline Coherent Potential Approximation (QC-CPA), which takes into account the correlation between the particles with a pair-distribution function. The mass operator includes geometric effects, caused by resonant behavior due to the shape and size of particles, cluster effects because of correlations between particles. Significant modifications of particle scattering properties can be observed.

[发布机构] THALES, Elancourt, France^1

[效力级别] 数学

[关键词] Coherent potential approximation;Effective dielectric permittivities;Electromagnetic scattering;Electromagnetic wave field;Lippman-Schwinger equation;Multiple-scattering theory;Pair distribution functions;Statistical ensembles