MONTE-CARLO SIMULATION OF SCATTERING FROM A LAYER OF VERTICAL CYLINDERS

The problem of electromagnetic scattering by a collection of randomly distributed vertical cylinders over a half-space dielectric is considered in this paper. The solution to this problem is sought in two ways. In the first approach, a Monte Carlo simulation is used which takes into account scattering terms up to second order. Closed-form expressions for the second-order scattering terms are derived for cylinders that are in the near field of each other. The second approach is based on the radiative transfer (RT) equations which are solved by an iterative method up to and including the second-order terms. Radar backscatter measurements were conducted at X band for a collection of metallic cylinders over a conducting ground plane and these results were compared with the Monte Carlo and radiative transfer solutions. The data were acquired polarimetrically from 144 independent spots of the cylinder layer at incidence angles ranging from 20-degrees to 60-degrees. The Monte Carlo simulation agrees well with the measured data and is used to check the validity of the results based on the RT theory for a medium with large particles. It is shown that both the phase function computed for the cylinders and the extinction matrix of the layer are overestimated in the RT solution because the correlation distance for the field inside the medium is smaller than the overall length of the cylinders.