Ray optical scattering by rectangular plates

The geometrical theory of diffraction is used to describe bistatic scattering from a rectangular flat plate as a function of incidence and observation angle for vertical polarization. RCS predictions based upon single diffraction are compared with numerical results from the method of moments for plates between 2 and 20 wavelengths on a side. Accuracy depends upon the form factor (ratio of height-to-width). When the form factor is greater than unity, the asymptotic theory provides a good match for the smallest plate, and accuracy improves for larger plates. When the form factor is less than unity, accuracy decreases due to grazing phenomena on wide plates viewed near edge-on incidence.