Modal expansions for electromagnetic scattering from perfectly conducting cylinders of arbitrary cross-section

The scattering of plane waves from perfectly conducting cylinders is studied, using the condition that the total field inside the cylinders must be zero. It is shown that the surface current density can always be expressed as a sum of proper modes. In general, fewer modes are required for calculating the scattered far field than are required for calculating the surface current density to the same accuracy. Two new approximate methods are introduced. These methods complement the method of physical optics, and the more accurate of them is suitable for calculating the scattering over a wide range of bistatic angles.