Validation of FD-TD modeling of the radar cross section of three-dimensional structures spanning up to nine wavelengths

The first experimental validation is reported of the finite-difference time-domain (FD-TD) method for modeling the monostatic radar cross section (RCS) of three-dimensional conducting structures. The structures modeled and tested span up to nine free-space wavelengths ( ). This represents a thirty-fold increase in electrical size over the previous analytically validated case of FD-TD modeling of radar cross section. It appears that the cases studied represent the largest detailed three-dimensional numerical scattering models of any type ever verified wherein a uniformly fine spatial resolution and the ability to treat nonmetallic composition is incorporated in the model. It was found that FD-TD provided a high modeling accuracy of 1 dB (with respect to the measurements) over at least a 40-dB dynamic range of radar cross section values for the nine-wavelength size objects, which exhibited such scattering physics as edge and corner diffraction, corner reflection (double bounce), and cavity penetration.