Propagation and Scattering by a Layer of Randomly Distributed Dielectric Cylinders Using Monte Carlo Simulations of 3D Maxwell Equations With Applications in Microwave Interactions With Vegetation

Transmission, scattering, and absorption by a layer of dielectric cylinders are studied in the context of microwave propagation through vegetation. The electromagnetic fields are calculated by numerical solutions of 3D Maxwell equations (NMM3D) using the method of Foldy Lax multiple scattering equations combined with the method of the body of revolution (BOR). Using the calculated transmission, we derive, the "tau", the optical thickness, which describes the magnitude of the transmission. Two cases are considered: the short-cylinder case and the extended-cylinder case. The case of short cylinders is that the lengths of cylinders are much smaller than the layer thickness, while the case of extended cylinders is that the lengths of the cylinders are the same as or comparable to the layer thickness. Numerical results are illustrated for vertically polarized plane waves obliquely incident on the layer of cylinders. The NMM3D results for the extended-cylinder case show large differences of transmission from the results of the other approaches, such as the effective permittivity (EP), the distorted Born approximation (DBA), and the radiative transfer equation (RTE). For the case of short cylinders, the NMM3D results are in close agreement with those of EP, DBA, and RIB.