Study of wall region and dielectric losses in a square hard horn

A numerical parametric study is presented of a circularly polarized square hard horn realized by dielectric-filled longitudinal corrugations. The horn is analyzed as an open waveguide. The attenuation introduced by losses in the dielectric material is calculated from the characteristic equation of the modified TE(10) mode. The far field, including radiation from the walls, is found from the electric vector potential. The attenuation, aperture efficiency and crosspolar sidelobe level are presented for different dielectric linings and waveguide sizes, and are compared with the performance of the smooth-walled horn.