High-frequency effects in field measurements of frequency-dependent soil properties

Field measurements of the frequency-dependent soil electrical properties at high frequencies (from 100 kHz up to several MHz) can be affected by unwanted electromagnetic effects. These effects can lead to significant errors in soil resistivity measurements. In this work the high-frequency effects are demonstrated. For this, the simulation model was developed based on the finite-difference time-domain method. Soil properties were calculated using the perpendicular dipole-dipole array. Different array dimensions, as well as uniform and multilayered soil models were considered. Simulation results are compared with those calculated analytically. It was shown that the electromagnetic effects increase with the depth of investigation and excitation frequency.