Estimating the Dielectric Permittivity in Nonconductive Composites by the Content and Morphology of Conducting Particles in the Microwave Frequency Range

The interrelation between the aspect ratio and the volume content of conducting particles has been theoretically established in the system “insulator–spheroidal particles” in the absence of macroscopic electrical conductivity at different relative dielectric permittivity values e/ed. The comparison of theoretical dielectric permittivity calculations with experimental data for the AlN–24 vol % Mo composite with spherical conducting particles has enabled the correction of earlier obtained ratios e/ed. The proposed new theoretical correlations take into account the mutual effect of conductive particles approaching the percolation threshold and make it possible to determine the dielectric permittivity of nonconductive composites by the volumetric content and morphology of conductive particles.