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

GTD analysis of the principal plane radiation patterns of open-ended circular cylindrical waveguide horns excited in the
TE_{11}
mode is presented, based on the theory of Kouyoumjian et al. [5]- [7] and the slope diffraction formulation [2]. The study enables one to predict accurately the
E
- and
H
-plane patterns over the neat 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.