A circular waveguide primary feed with a corrugated concave disk at its aperture.

The paper deals with the theoretical and the experimental investigations regarding the performance of a circular waveguide feed with a corrugated concave disk at its aperture. The circular waveguide is excited in the dominant (TE11) mode. A theoretical method is presented to obtain the far-field patterns of such structures. The improved symmetry in the field patterns (vertical and horizontal) of these feeds, as compared to those of the feeds with flat corrugated disks of identical diameter and corrugation dimensions are indicated. The experimental data obtained from a test feed confirms the theoretical calculations.