Compound-taper feed horn for NASA 70-m antennas

A compound taper feed horn structure is described that was used to move the phase center of a corrugated feed horn without any significant degradation in its other major characteristics. Based on this technique, an X-band feed horn has been designed for use in the National Aeronautics and Space Administration's (NASA) 70-m antennas. The compound taper structure consists of a conventional corrugated flared section (a standard 22-dB feed horn) and a corrugated straight section. This feed horn is designed to move the phase center of the standard feed horn to a desired location without the addition of significant loss to the system. The feed horn was checked extensively by a computer program. Excellent agreement between theoretical and measured results was established, and the feed horn was shown to perform as well as the standard feed horn for all practical purposes.>