Sensitivity of normal incidence scattering predictions to material characteristics

Many methods exist to predict the electromagnetic scattering, but the object material characteristics are key input variables. This paper demonstrates the relationship between the uncertainties in these material characteristics and the accuracies of the scattering predictions. The material characteristics of a given dielectric were measured by two separate X-band waveguide set-ups, Scattering measurements were made of the given dielectric backed with and without a metal square plate at normal incidence. Scattering predictions were calculated with: (1) reflection coefficients from transmission line theory and physical optics; and (2) XPATCH, a high frequency scattering prediction code. It was found that variations in scattering predictions were proportional to variations of the imaginary part of the permittivity. Furthermore, the magnitude of the variations in these corresponded to the relative magnitude of the reflection coefficient.