Electromagnetic scattering by a bounded obstacle in a parallel plate waveguide

This paper concerns scattering of an electromagnetic wave by a bounded object located inside a parallel plate waveguide. The exciting field in the waveguide is either an arbitrary source located at a finite distance from the obstacle or a plane wave generated in the far zone. In the latter case, the generating field corresponds to the lowest propagating mode (TEM) in the waveguide. The analytic treatment of the problem relies on an extension of the null field approach, or T-matrix method, originally developed by Peter Waterman, and later generalized to deal with object close to an interface. The present paper generalizes this approach further to deal with obstacles inside a parallel waveguide. This problem shows features that reflect both the two-dimensional geometry, as well as the three-dimensional scattering characteristics. The analysis is illustrated by several numerical examples