Far field scattering of Gaussian beam by an infinitely long conducting circular cylinder

The Gaussian beam scattering from an infinitely long conducting circular cylinder with large size parameter and located in the far zone from the source of excitation is investigated. This problem had bean solved via modal expansion technique. However, in case where the scatterer size is extremely large compared with incident wavelength, the previously obtained solutions are no long practical. In this paper, a practical treatment is developed. The Gaussian beam is expanded in terms of continuous plane waves with amplitudes and phases given by a Gaussian weighting functions. The continuous plane wave spectrum of the Gaussian beam is obtained. Since the scatterer size is very large compared with the incident wavelength, the scattering of each plane wave by the conducting circular cylinder is computed via geometrical optics technique. Thus, the evaluation of the Gaussian beam scattering from the conducting circular cylinder reduces to evaluating the inverse Fourier transform to the scattered plane waves. Numerical results using a code developed under MATLAB environment is obtained. The obtained solution is compared with the previously published solutions that are based on modal expansion technique and good agreement is achieved.