FDTD ANALYSIS OF 2-DIMENSIONAL TRANSIENT SCATTERING OF CYLINDRICAL WAVE VIA BURIED CONDUCTING OBJECTS

It is important to know the scattering properties of objects buried un derground so that the techniques of imaging the buried objects by elec tromagnetic waves may be established. This paper analyzes numerically the transient scattering characteristics by the finite difference time domain (FDTD) method where an infinitely long perfect conductor of ar bitrary cross section is buried in the ground and an infinitely long c urrent source is located above the ground surface parallel to the obje ct. The calculation error resulting from the approximation of the scat tering object by square mesh is decreased by introducing the field int erpolation which satisfies the boundary conditions of the scattering s urface. The spatial distribution of the electromagnetic field at each step of the calculation is shown. Moreover, the propagation characteri stics of the wave near the ground surface and the scattering character istics of various objects are studied and the presence of two types of waves, i.e., direct and lateral, is confirmed between the source and ground and between thr:object and ground.