Modelling of buried cylindrical dielectric structures

To solve the inverse problem in ground penetrating radar by minimization of a cost function in an iterative process, a fast solver for the direct problem is required. For this purpose the authors propose a hybrid method which is based on spectral domain methods in conjunction with the exact solution for dielectric circular cylindrical objects. The advantage of spectral domain methods is, that they can describe the ground as well as the inevitable air gap between the antenna and the ground as a set of dielectric layers of defined thickness and infinite lateral extents. No absorbing boundaries are required to limit the size of the structure. Multiple reflections between cylinder and the air ground interface can by determined by an iterative procedure. The total electric field is calculated in the plane of antenna as the result. The paper includes the description of the method as well as the comparison of calculated results to measurements of hidden objects shallow in the ground, obtained with a monostatic single frequency CW radar sensor.