Shostak S. Dielectric losses in matrix dispersed systems and porous media

Electromagnetic vawe absorption by the matrix dispersed systems (MDS), statistical mixtures, and porous dispersed systems (PDS) is investigated in the electrostatic approximation. Interaction of such systems with the low-frequency electromagnetic radiation is considered, primarily, in the Maxwell-Garnett approximation. Dielectric losses are calculated for a range of MDS: MDS with spherical inclusions of different physical nature; MDS with two-layered spherical inclusions having anisotropic shell; MDS with statistically distributed conducting ellipsoidal inclusions; conducting MDS with conducting inclusions at arbitrary concentration of the inclusions. In the electrostatic approximation with accounting for multipolar interaction between inclusions it is elaborated a theoretical method for calculating the effective permittivity of MDS with either spherical homogeneous or two-layered inclusions. When calculating frequency dependence of the effective permittivity for this case, size distribution of the inclusions as well as randomnicity of their localization in the matrix were accounted. It is shown that determination of the effective permittivity for MDS with two-layered inclusions is quite equivalent to the same problem but for MDS with homogeneous inclusions, if only the dipole-dipole interaction between the inclusions is accounted. One only need to replace the polarizability of the homogeneous particle by that of two-layered one in the expression for the effective permittivity. Problem of the effective permittivity calculation for porous media is considered in the local porousity approximation. It is obtained an integral equation for solving the effective permittivity, and its particular solutions for percolating porous media are analyzed. The inversed electrodynamical problem for this equation is solved.