The main components of a multifrequency antenna system for propagation experiments with the large telecommunications satellite Olympus are reviewed. The antenna system consists of a classical dual reflector Cassegrain antenna with a single aperture multifrequency primary feed system. The 12/20/30 GHz beacons of Olympus provide stable and pure signals for the direct measurement of atmospheric influences on radio wave propagation, and they provide a directional reference for the alignment of ground station antennas. The geometry and the electrical characteristics of a classical Cassegrain antenna, with a corrugated horn primary feed, are considered, including geometrical relationships, strut geometry, subreflector size, illumination taper, blocking, surface accuracy, polarization efficiency, and on-axis polarization discrimination. The feed system consists of a horn antenna and a microwave network. At each of the beacon frequencies, the radiation pattern of the feed system is required to have axial symmetry, low cross polarization, and a prescribed amplitude decay. These requirements can be met by using a corrugated horn supporting balanced hybrid modes at these frequencies.
Multifrequency Antenna System for Propagation Experiments with the Olympus Satellite (Revised)
1988
67 pages
Report
Keine Angabe
Englisch
NTIS | 1989
|OPEX: (Olympus Propagation EXperiment)
NTRS | 1988
|Opex: (Olympus Propagation Experiment)
NTIS | 1988
|