A spherical reflector antenna for communication satellite earth stations
Abstract
An experimental spherical-reflector microwave antenna is described. It has a movable broad-band feed incorporating a concave subreflector, which permits + or - 7 deg beam-steering without loss of gain. Overall efficiency was measured as 50%, but this could be raised to 58% by eliminating reflector distortion. The first sidelobe level was -10.6db and antenna noise temperature was 30 K. Possible improvements include raising efficiency by allowing some gain variation on scanning. Optimum design then depends on system noise temperature and scanning requirements, but it is concluded that up to 75% on-axis efficiency is obtainable. Loss in gain at 7 deg scan is typically 0.3db.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- December 1972
- Bibcode:
- 1972STIN...7516703M
- Keywords:
-
- Antenna Feeds;
- Communication Satellites;
- Ground Stations;
- Microwave Antennas;
- Reflectors;
- Amplification;
- Noise Temperature;
- Sidelobes;
- Spherical Antennas;
- Communications and Radar