Statistics of electromagnetic near fields scattered from 3D AP mines buried under random rough surface calculated using the steepest descent fast multipole method (SDFMM)

Abstract

The Steepest Descent Fats Multilevel Multiple Method (SDFMM) is used to analyze the distorting effects of random rough ground surfaces on scattered electromagnetic waves from buried TNT mines. The SDFMM method is an integral equation- based fast algorithm that is well suited for 2D penetrable rough surfaces in the frequency domain, and it is used to calculate the unknown surface currents on both the rough ground and the buried target as well. In this study all interactions between the rough interface and the buried target are taken into account. The scattered near field E- patterns of an incident Gaussian beam are calculated at different locations above the mean plane of the dielectric rough interface. The receiver locations are chosen to simulate GPR measurement protocols. The dimensions and burial depth of the TNT mine are smaller than the free space wavelength with material slightly different from the surrounding soil. The average and the standard deviation of the scattered fields for just the target are calculated and results showed that the presence of the rough interface tremendously distorts the target signal even for the small roughness parameters. Moreover, results showed the degradation of signal as the TNT mine is located away from incident beam. This knowledge can significantly contribute to inventing better sensing systems for less false alarm detection strategies.