The finite difference time domain (FDTD) method is used to analyze a practical ground penetrating radar (GPR) antenna system operating above lossy and dispersive grounds. The antenna is of the resistor-loaded bow-tie type and the analysis is made for two known soil types, namely Puerto Rico and San Antonio clay loams. The soil is modeled by a two term Debye model with a static conductivity and it is matched to the mentioned soils by using curve fitting. The FDTD scheme is implemented by the auxiliary differential equation (ADE) method together with the uniaxial perfectly matched layer (UPML) absorbing boundary conditions (ABC). In order to model a real GPR environment, ground surface roughness and soil inhomogeneities are also included. The effect of soil properties on the GPR response and antenna input impedance is presented. Thus the ability to detect buried metal and plastic pipes is investigated.
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