A comparison of high-frequency scattering determined from PO fields enhanced with alternative ILDCS

In order to compare the accuracy of 'source-based' and 'diffraction-cone' incremental length diffraction coefficients (ILDCs), the high-frequency scattered far fields of a perfectly conducting circular disk are computed using physical optics (PO) enhanced with source-based and diffraction-cone ILDCs. For angles of incidence and scattering that are near grazing to the disk, the diffraction-cone ILDCs predict bistatic scattered far fields that are generally much greater than the exact far fields and that are much less accurate than the scattered far fields predicted by the source-based ILDCs. These results lead us to conclude that the source-based ILDCs are preferable for improving upon the accuracy of PO fields computed with general purpose computer codes. Index Terms--High frequency scattering, incremental length diffraction coefficients, physical theory of diffraction.