GTD analysis of the radiation patterns of open-ended circular cylindrical waveguide horns

GTD (geometrical theory of diffraction) analysis of the principal plane radiation patterns of open-ended circular cylindrical waveguide horns excited in the TE11 mode is presented, based on the theory of Kouyoumjian et al. (1974, 1975) and the slope diffraction formulation. The study enables one to predict accurately the E- and H-plane patterns over the near and far sidelobes and backlobes of the horn, and a good agreement is noticed between the calculated and measured radiation patterns obtained with an experimental circular waveguide horn excited in the dominant mode.