Impedance Analysis of Soil Dielectric Dispersion (1 MHz–1 GHz)

Abstract

The complex permittivity of saturated kaolinite, bentonite, and Ottawa sand samples was studied in the range from 1 MHz to 1 GHz. Measurement procedures and equipment calibration for the whole frequency range are described. The impedance spectroscopy was used to analyze the data in the impedance and admittance complex planes. Thus, simple circuits of well-known response were obtained from the analysis. This technique is briefly reviewed. The Maxwell-Wagner loss mechanism for the saturated samples of kaolinite, bentonite, and Ottawa sand could be identified by careful analysis of the data in the impedance and admittance planes. It was observed that this mechanism is seriously distorted by ion diffusion and ohmic conductivity that make interpretation of data in the dielectric spectrum difficult. The present analysis allowed for the determination of the polar and ohmic contributions of soil particles and water to the measured permittivity. The effect of ion displacement is addressed, and its effect on soil dispersion is discussed.