New method for temperature dependent dielectric property investigation in polymer composite materials

Industrial processing of products made from light weight fiber reinforced composites could benefit from microwave heating providing the temperature dependent dielectric properties of the composite materials are known. Three methods of permittivity measurement at ambient temperature are compared: cavity perturbation, coaxial probe and SPDR, Split-Post Dielectric Resonator. The measured values differ significantly for each setup. Therefore a reverse simulation is performed. It is based on a new approach which utilizes the slope, ΔT/Δt of microwave heating curves recorded in a cavity perturbation type setup as indicative for changes in the imaginary part of the permittivity. Two simulation tools are compared: COMSOL^® and Quickwave^®.