EQUIVALENT MODEL OF PERFECTLY CONDUCTING RANDOM CYLINDERS

Abstract

The problem of electromagnetic scattering due to perfectly electrically conducting(PEC) random angularly corrugated cylinder, placed in free space, has been solved numerically with the help of method of moments. The field is normally incident with parallel polarization of the electric field. Two models of arbitrarily shaped cylinder are given. Statistics of geometrical properties such as root mean square area, circumference, maximum radius and lateral width of these cylinders are also determined. Scattered field due to arbitrarily shaped cylinder is obtained numerically. Its reliability is determined using optical theorem. An ensemble of fifty thousand cylinders is used for each simulation. Considering total scattering cross section as the invariant parameter, it is shown that a circular cylinder is better equivalent than a strip. It has also been shown that equivalent radius is bounded by isoperimetric inequality and can be approximated from the bounding values. Total scattering cross section is highly correlated with lateral width and the joint pdf of these two quantities is approximately Gaussian. An elliptical cylinder is introduced as an equivalent model. Parameters of equivalent elliptic cross section are obtained using lateral width and total scattering cross section of random cylinder. It is observed that the two axes of equivalent elliptic cylinder are inversely proportional with each other and area of mean radius circular cylinder is the proportionality constant. It is concluded that if lateral width and mean radius of random cylinder is known then one can predict total scattering cross section of random cylinder with the help of equivalent elliptical cylinder.