Determination of the Complex Permittivity of Vermiculite using a Microstrip Line

The way different materials react when submitted to microwave radiation depends strongly on its dielectric properties. Thus, in industrial processes that employ microwaves it is important to previously know the properties of the material to be processed in particular its dielectric characteristics. It is necessary to know the complex permittivity of the material in order to design a suitable cavity for processing, taken into account its dielectric characteristics. Another important factor to be considered is the variation of the AC conductivity, which is strongly influenced by the behavior of the charge carriers with frequency. In the present study, a microstrip line was used in the determination of the complex permittivity of vermiculite in frequencies ranging from 1.60 GHz to 2.00 GHz and at 2.45 GHz. The technique is based on the measured S-parameters, followed by a numerical determination through a MATLAB code based on the Nicolson - Ross - Weir non- iterative method. The method used in this research presented good accuracy and is very suitable for studies involving phyllosilicate minerals.