Theory of radar return from terrain

It is often convenient to have theoretical expressions for the back-scattering cross-section of terrain, in order to properly organize experimental data, and to permit complete analysis of radar operation. Two models have been proposed for this purpose. The first, applicable to roadways and similar smooth surfaces, gives the return in terms of the roughness, the height correlation function and the complex dielectric constant of the surface, and is in excellent quantitative agreement with experiment. The second model, applicable to grass or similar cylindrical vegetation, gives the return as a function of the number, size, and complex dielectric constant of the cylindrical scatterers; it is in qualitative agreement with experiment. Applications to the problem of characterizing terrain, and to radiometry are mentioned.