1.2 Meter Shielded Cassegrain Antenna for Close-Packed Radio Interferometer
| Autor: | Koch, Patrick M., Raffin, Philippe, Huang, Yau-De, Chen, Ming-Tang, Han, Chih-Chiang, Lin, Kai-Yang, Altamirano, Pablo, Granet, Christophe, Ho, Paul T. P., Huang, Chih-Wei L., Kesteven, Michael, Li, Chao-Te, Liao, Yu-Wei, Liu, Guo-Chin, Nishioka, Hiroaki, Ong, Ching-Long, Oshiro, Peter, Umetsu, Keiichi, Wang, Fu-Cheng, Wu, Jiun-Huei Proty |
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| Rok vydání: | 2010 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1086/658675 |
| Popis: | Interferometric millimeter observations of the cosmic microwave background and clusters of galaxies with arcmin resolutions require antenna arrays with short spacings. Having all antennas co-mounted on a single steerable platform sets limits to the overall weight. A 25 kg lightweight novel carbon-fiber design for a 1.2 m diameter Cassegrain antenna is presented. The finite element analysis predicts excellent structural behavior under gravity, wind and thermal load. The primary and secondary mirror surfaces are aluminum coated with a thin TiO$_2$ top layer for protection. A low beam sidelobe level is achieved with a Gaussian feed illumination pattern with edge taper, designed based on feedhorn antenna simulations and verified in a far field beam pattern measurement. A shielding baffle reduces inter-antenna coupling to below $\sim$ -135 dB. The overall antenna efficiency, including a series of efficiency factors, is estimated to be around 60%, with major losses coming from the feed spillover and secondary blocking. With this new antenna, a detection rate of about 50 clusters per year is anticipated in a 13-element array operation. Comment: 35 pages, 14 figures; accepted for publication in PASP |
| Databáze: | arXiv |
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