Modeling dielectric permittivity of polymer composites at microwave frequencies

A modification of the Lichtenecker–Rother model is proposed for the dielectric permittivity of polymer composites that takes into account aggregation of filler particles into clusters. The governing equations for the real and imaginary parts of the complex permittivity of a composite involve three adjustable parameters with transparent physical meaning. These quantities are determined by fitting experimental data on a number of polymers reinforced with ceramic, magnetic and carbon particles. Good agreement is demonstrated between the results of simulation and observations on the dielectric constant and dielectric loss at microwave frequencies. It is shown that the model can be applied to extract dielectric parameters of filler from observations on polymer composites.