Dielectric constant calculation based on mixture equations of binary composites at microwave frequency

The effective microwave dielectric constants of binary composites are examined through mixture equations in this paper. The ratios of dielectric constant of filler material to that of matrix material are studied from 0.77 to 24.55 and 0.21 to 9.53 in small and large volume fractions of filler material, respectively. The most adequate mixture equation for predicting the dielectric constants of binary composites is suggested. It was found that all mixture equations could give reasonably good predictions under similar dielectric constant between filler and matrix material situation and in the small volume fraction region. The effective medium theory model matched well for all volume fractions and a small amount secondary phase existence. Moreover, precision can be improved by the porosity corrected relative permittivity of composites.