Spectral Projection Model for Analyzing Electromagnetic Scattering from Two Dimensional Conducting Objects

In this paper, a novel new formulation based on the addition theorem for Bessel and Hankel functions is developed for electromagnetic scattering from two-dimensional, conducting objects. The addition theorem is used to represent the Green's function as a projection of spectral signatures of source points on to spectral signatures of the observation points. The spectral signatures are defined in terms of the Bessel and Hankel functions. Known as the spectral projection model, this formulation allows one to define the scattered signal in terms of a spectral signature of a virtual image current as opposed to induced surface currents. The spectral signatures do not have to be defined in space and can easily be related to the scattered field in the far-field. MATLAB simulations of scattering from two-dimensional objects are used to verify and validate this new formulation. The model is applied to infinitely long conducting cylinders with elliptical cross-sections. The results from the spectral projection model are compared with those from the Method of Moments (MoM) for accuracy and speed. The results indicate that the new model performs well for cylinders with elliptical cross-sections for moderate axial ratios. For larger axial ratios, the model has to be modified to account for the wider spectral signatures. A new multi-reference spectral signature is defined and shown to work for scattering from cylinders with large axial ratios.