RANDOM MEDIUM MODEL APPROACH TO SCATTERING FROM A RANDOM COLLECTION OF DISCRETE SCATTERERS

The random medium model has been used quite successfully in the interp retation of active and passive microwave remote sensing data from eart h terrain. In the random medium model, a correlation function with ass ociated mean and variance is used to describe the random permittivity fluctuations. Most of the correlation functions used, thus far, in the random medium model have been of exponential form, or of other simple expressions derived from physical arguments. In this paper, we calcul ate the correlation function for a specific physical model of the rand om medium which is a random collection of discrete scatterers imbedded in a background medium of constant permittivity. Correlation function s are calculated for impenetrable and penetrable spherical scatterers. Once the correlation function is obtained, the strong fluctuation the ory is used to calculate the effective permittivity. Then, the distort ed Born approximation is used to calculate backscattering coefficients for a halfspace configuration. Theoretical results are illustrated by comparing effective permittivities and backscattering coefficients ob tained from the penetrable and impenetrable models.