Multi-frequency electromagnetic scattering from inhomogeneous rectangular waveguides using shifted frequency equivalence

The shifted frequency internal equivalency (SFIE) principle is applied to multi-frequency electromagnetic scattering problem from a two-dimensional inhomogeneous rectangular waveguide. As is well known, the surface integral formulation is only applicable to homogeneous structures, and in the volume integral formulation it is necessary to repeat the solution process by generating data at each incident field frequency. The author shows that, the volume interaction part of the data may be generated only at a single frequency and be utilized at other frequencies over a wide frequency band. The use of the SFIE principle for one-dimensional problems have demonstrated earlier. In this article, its extension to two-dimensional structures is presented.