RADIATION CHARACTERISTICS OF A CORRUGATED CONICAL HORN.

The corrugated conical horn is useful as the primary radiator of a Cassegrain antenna because of its axially symmetric beam and low sidelobe level. For broadband applications the frequency characteristic of the horn must come into consideration. To discuss the quality of the horn this paper introduces a parameter x, which is based on the groove dimensions of the corrugation. Variation of the radiation pattern with frequency is then shown with respect to x. The variation also depends on the variable t, which is based on the aperture diameter, horn length and observation distance. It is found that to obtain an axially symmetric beam, x must be taken to be around but less than 2. 405, while t must exceed 0. 4 at the lowest frequency of interest for constant beam width.