Dielectric properties of SiCf/SiC composites

Abstract

The aim of this research work is to present a study of the microwave dielectric properties of three dielectric composites of periodic structure with Nicalon SiC fiber, Hi-Nicalon SiC fiber and SCS6 SiC fiber which are incorporated in a ceramic matrix SiC (SiCf/SiC). The simulated values of the complex permittivity were compared to those obtained by different mixing laws using finite element method. McLachlan's theory is able to predict the effective permittivity of the structures studied, even for a high volume fraction and a high contrast. Dielectric properties behavior of these composites at the microwave frequencies in X band can be accurately fitted by the Generalised Looyenga law if adjusting the value of the exponent h. The obtained values for the exponent parameter of this law allow inferring the particles shape.