Internal reflections at the open end of a semi-infinite waveguide

The reflection coefficients of those waveguide modes, with propagation constants near cutoff, which are excited at the open end of a semi-infinite parallel-plate waveguide for frequencies from the microwave to the optical region are discussed in this paper. The reflection coefficients are obtained from a recently developed form of the factorization formula for the Wiener-Hopf kernel associated with this problem. This particular formula is suitable for numerical processing over the complete frequency spectrum. Results of representative calculations are presented graphically as functions of the ratio of waveguide size to wavelength.