RADIATION-PATTERNS FOR 2-D GPR FORWARD MODELING

The electromagnetic (EM) radiation of a ground-penetrating radar (GPR) antenna is affected by the presence of the air-earth interface and de pends on the geometrical and physical characteristics of the antenna. To simulate the radiation pattern with grid methods without the explic it modeling of these features, an equivalent solution is obtained by u sing a composite source concept. The 2-D analytic solution correspondi ng to magnetic and electric sources located at the same grid point is computed. This solution constitutes a basis for the construction of a composite source located in a small region of the numerical mesh. The field is obtained for transverse magnetic (TM) and transverse electric (TE) waves in anisotropic media because the use of anisotropic conduc tivity is an alternative approach to simulating different radar apertu res. Realistic radiation patterns are obtained from simple combination s of magnetic and electric sources by analogy with seismic shear stres ses. The source parameterization is used for GPR simulation, and singl e radargram traces obtained with the modeling algorithm are cross chec ked with the analytic solution.