Frequency dependent impedance of two-layer soil

In majority of work, the authors consider that the soil is homogeneous with a uniform resistivity. But in reality, it's not always right because of the variety of the layer soil. In fact, in this paper, and in order to study the frequency dependent impedance, we assume that the soil is with two layers with two different resistivities. The Matlab program was used to calculate the frequency -dependent impedance of the soil in two cases, the first one if the soil is homogenous the second one is with a heterogeneous soil. As a result, for a two layer soil, the soil impedance is more significant in case of which the top soil-layer resistivity is less than the bottom-layer resistivity.