On the GTD scattering by a polygonal cylinder

Using Keller's geometrical theory of diffraction (GTD) the field diffracted by a wedge is infinite at the shadow and reflection boundaries. In general, uniform diffraction coefficients must be used to provide continuous fields at these boundaries. In this communication it is shown that by properly adding the singular contributions from a pair of adjacent edges, Keller's diffraction coefficients yield a continuous far-zone field at the reflection boundaries of a polygonal cylinder illuminated by a plane wave. Furthermore the procedure is justified by noting that the uniform diffraction coefficients reduce to the Keller diffraction coefficients for this case.