Determination of Effective Constitutive Properties of Metal Powders at 2.45 GHz for Microwave Processing Applications

摘要

A reflection-transmission based rectangular waveguide approach for measuring the effective constitutive properties of metal powders at 2.45 GHz is presented. The measured effective dielectric properties of these metal powders are quite important for sintering of metal powders using microwaves, which is a new area of research. The proposed method is based on placing the metal powders of varying density into a standard glass tube, which is then positioned inside a specially designed waveguide holder for measuring the scattering coefficients at 2.45 GHz using a vector network analyser. The effective constitutive properties of the metal powders are obtained in terms of the measured scattering coefficients using the proposed two step approach. In order to validate the accuracy of the measured material properties, an electromagnetic core-shell model of the metal powders is developed. Finally, the effective dielectric properties of Cu and stainless steel powders are measured and compared with the values obtained using the electromagnetic model.