A reappraisal of the validity of IEM model

A surface scattering model based on the integral equation method is examined in terms of its applicability to laboratory measurements. The Fresnel reflection coefficients used in the model have been approximated as a function of the incidence angle at low frequency and as a function of the specular angle at high frequency. Based on a limited set of experimental measurements, a transition function is suggested for estimating the Fresnel reflection coefficients in the intermediate regions. Results of comparison indicate that the IEM is accurate and practical to use. Issues raised from dielectric information are also addressed.