Astronomy and Astrophysics – Astronomy
Scientific paper
Jul 2000
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000spie.4015..308f&link_type=abstract
Proc. SPIE Vol. 4015, p. 308-318, Radio Telescopes, Harvey R. Butcher; Ed.
Astronomy and Astrophysics
Astronomy
4
Scientific paper
Phased array feeds offer the possibility of more efficient use of large radio astronomy reflector antennas by providing more closely spaced beams over a wide field of view and higher aperture efficiency in each beam than have been realized with horn feeds. This paper examines the array design constraints imposed by complete sampling of the fields near the reflector focus. In particular, array element spacing must be less than 1 (lambda) for large F/D reflectors and less than about 0.7 (lambda) for F/D < 0.5. This rules out conventional horns as array elements and sets a limit on the array bandwidth. The receive-only case of radio astronomy permits the use of number of signal combining techniques that do not degrade system sensitivity. Because practical arrays are of finite extent, and unwanted noise from the antenna surroundings is largely coherent between the elements, neither field conjugate nor maximal-ratio diversity methods of array weight optimization can be used. A modified form of field matching is a good starting approximation, however. Correction of reflector errors is examined briefly.
Bradley Richard F.
Fisher Richard J.
No associations
LandOfFree
Full-sampling array feeds for radio telescopes does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Full-sampling array feeds for radio telescopes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Full-sampling array feeds for radio telescopes will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1482817