A hybrid technique for analyzing corrugated and noncorrugated rectangular horns

A hybrid technique is proposed to solve the entire problem of corrugated and noncorrugated rectangular horns without the usual approximations. The horn antenna is simulated by a multistepped waveguide structure radiating into half-space. The procedure is composed of three steps. First, assuming the horn to be terminated by infinite metallic flange, the aperture problem is accurately solved by a hybrid modal-spectral method (HMSM). Second, the modal analysis (MA) method and scattering matrix concept of waveguide discontinuities are employed to solve the transverse multidiscontinuity problems. Finally, the two methods are combined (MA-HMSM) to solve the entire problem of the horn antenna. The proposed technique allows to obtain not only the radiation patterns, but also the reflection and near-field characteristics of the horn, without any restriction on the geometry (semiflare angles, profiled horn contours, corrugations). A good agreement between theoretical predictions and experimental results has been obtained for several horns.