Double-Spherical Cassegrain Reflector with a Single Displaced Feed.
Abstract
For multibeam operation of an antenna, it is necessary for some of the feeds to be displaced from the axis of symmetry. The effects of such displacement are investigated for the double-spherical Cassegrain reflector. Aperture blocking, phase error, radiation pattern, aperture efficiency, beam-width and sidelobe level are studied as functions of the displacement angle xi. An attempt to improve the performance of the antenna by tilting the feed through an angle zeta is made, and a practical feed pattern is used to evaluate the system. The results indicate that very narrow beamwidth and reasonably low sidelobes can be obtained, which are essential for multibeam antennas. The decrease of the aperture efficiency due to a displacement and a tilt of the feed is studied in detail for different reflector sizes and feed pattern. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1973
- Accession Number
- AD0764778
Entities
People
- Akira Ishimaru
- H. K. Tsiang
- Vincent K. Wong
Organizations
- University of Washington