ABSTRACT
The problem of laser beam scattering from circular cylinder coated by organic dielectric polymeric material based on polyaniline is investigated. In this study, polyaniline is prepared in laboratory, it was chemically synthesized, via the chemical oxidation of aniline by persulfate anion in aqueous solution. It showed good yield and intermediate electrical conductivity (a =5 S/cm). This conductivity assigns it as a semiconductor material. Polyaniline was characterized by different methods of analysis such as: thermogravimetric analysis, electric conductivity, infrared and UV—visible absorption spectroscopy. The prepared polymer was formulated for laser beam scattering studies. 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 and coated by polyaniline dielectric material is investigated. This problem had been solved via modal expansion technique. The Gaussian beam is expanded in teens 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. 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. Experimental measurements are worked out for He-Ne laser beam of wave length ( A, = 0.6328 gm) incident on conducting circular cylinder coated by different thickness of polyaniline material. The attenuation of the scattered field due to this dielectric material is computed and compared by the measured results.