Determination of Dielectric Properties and Humidity of Vermiculite Using S-Parameters

In the present study it is described the determination of the dielectric properties of a micaceous mineral, namely vermiculite, using S-parameters. AC conductivity, permittivity, loss tangent, and humidity were determined. The dependence of the dielectric constant and the humidity was investigated. Another important factor considered is the variation of the AC conductivity with frequency, which is strongly influenced by the behavior of the charge carriers for different frequencies and the material's losses. The technique addressed in this work, is based on the measured S-parameters of a microstrip line structure, followed by numerical calculations based on the Nicolson - Ross - Weir method. The presented method is accurate and can be used for further studies to understand the behavior of other minerals or soil when submitted to electromagnetic fields.