Monte-Carlo simulation of electromagnetic scattering from a heterogeneous two-component medium

A numerical solution for scattering from a random collection of long vertical cylinders and spheres above a ground plane is developed to examine the validity of radiative transfer theory when applied to vegetation canopies. Numerical simulations, while frequently computationally intensive, give detailed statistical information, including the phase-coherence, directly related to the scattered fields themselves. Electromagnetic scattering properties of the heterogeneous medium, such as the backscattering coefficient and phase-statistics, are determined including interactions up to second order. The second-order, near-field, and sphere-cylinder interaction has been computed for nonuniform illumination of one particle by its pair using a novel technique based on reciprocity. The application of this reciprocity-based approach is validated using the method of moments. The Monte-Carlo simulation results are compared with corresponding analytical solutions obtained from radiative transfer (RT) theory for the purpose of examining the significance of limitations in the underlying assumptions of RT in formulating solutions for EM scattering from vegetation media