Analysis of the Main Scattering Mechanisms in Forested Areas: An Integral Representation Approach for Monostatic Radar Configurations

In this paper, a coherent forest scattering model based on the electric-field integral representation is developed. This model gives the scattered field by the forest, resulting from the interaction of an electromagnetic plane wave with its main elements (trunks, branches, and plane ground) in a frequency range of 100 to 400 MHz. The Method of Moments is used to solve the electric-field integral equation. In our treatment, there are three possible scattering mechanisms that contribute to the scattered field defined as follows: 1) single-; 2) double-; and 3) triple-bounce scattering mechanisms. The internal fields inside the tree trunks and branches are calculated by considering all of the multiple-scattering interactions within the forest. Our model is then constructed by coherently summing the three scattering mechanisms previously given. We can also obtain an approximate result by ignoring some or all of the multiple-scattering interactions in the calculation of internal fields inside the trees. The aim of this paper is, first, to determine the relative contribution of each scattering mechanism to the total scattered field, followed by the relative contribution of tree-trunk and branch scattering responses to the total scattering field, and, finally, the multiple-scattering interaction effects on the total backscattered field.