Microwave effective permittivity of the layered dielectrics and composites using the nonlinear mixing model

Abstract

This paper presents a novel mixing formula for computing the effective complex permittivity of layered dielectrics and composites in the microwave frequency range. The newly derived formula for the slab-shaped mixed dielectrics and composites is substantially different from other mixing equations present in the literature, as the proposed formula computes the effective permittivity in terms of the weighted volume ratio and the dielectric properties of the constituent materials. The weighted volume ratio takes into account the effect of the electric field configuration of microwave field interacting with the material under test. The applicability of the proposed mixing model is tested using both the simulated and the measured data for a number of cases. The effective complex permittivity of all the equivalent mixed dielectric samples computed using the proposed mixing formula matches quite well with the corresponding data measured in the microwave frequency range. Finally, the relative percentage error between the measured effective permittivity and its computed value using the proposed mixing formula is calculated in order to quantify the results.