Radiation from the open end of a circular waveguide with a conical flange in the approximation of the geometrical theory of diffraction - The scalar problem

An analysis is presented of the short-wave asymptotic behavior of the field of radiation from the open end of a circular waveguide with a conical flange. The geometrical theory of diffraction, the focal expansion, and the Kirchhoff approximation are used to analyze the multiple-diffraction fields. A comparison is made with Vainshtein's (1966) exact solution in the limiting case of a flangeless circular waveguide and with the Kirchhoff approximation.