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The MAP Satellite Feed Horns

Barnes, Chris and Limon, Michele and Page, Lyman and Bennett, Charles and Bradley, Stuart and Halpern, Mark and Hinshaw, Gary and Jarosik, Norm and Jones, William and Kogut, Al and Meyer, Stephan and Motrunich, Olexei and Tucker, Greg and Wilkinson, David and Wollack, Ed (2002) The MAP Satellite Feed Horns. Astrophysical Journal Supplement Series, 143 (2). pp. 567-576. ISSN 0067-0049. doi:10.1086/342833.

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We present the design, manufacturing methods, and characterization of 20 microwave feed horns currently in use on the Microwave Anisotropy Probe (MAP) satellite. The nature of the cosmic microwave background (CMB) anisotropy requires a detailed understanding of the properties of every optical component of a microwave telescope. In particular, the properties of the feeds must be known so that the forward gain and sidelobe response of the telescope can be modeled and so that potential systematic effects may be computed. MAP requires low emissivity, azimuthally symmetric, low-sidelobe feeds in five microwave bands (K, K_a, Q, V, and W) that fit within a constrained geometry. The beam pattern of each feed is modeled and compared with measurements; the agreement is generally excellent to the -60 dB level (80° from the beam peak). This agreement verifies the beam-predicting software and the manufacturing process. The feeds also affect the properties and modeling of the microwave receivers. To this end, we show that the reflection from the feeds is less than -25 dB over most of each band and that their emissivity is acceptable. The feeds meet their multiple requirements.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle
Limon, Michele0000-0002-5900-2698
Page, Lyman0000-0002-9828-3525
Halpern, Mark0000-0002-1760-0868
Motrunich, Olexei0000-0001-8031-0022
Tucker, Greg0000-0002-6954-6947
Wollack, Ed0000-0002-7567-4451
Additional Information:© 2002 The American Astronomical Society. Received 2002 February 12; accepted 2002 July 12. T he design, building and testing of the MAP feeds took over 2 years. The Princeton machine shop was invaluable in this program, especially Glenn Atkinson, who spent a year on machining alone. Ken Stewart and Steve Suefert kept NASA/GSFC’s GEMAC indoor beam mapping facility mapping for weeks at a time. Charles Sule inspected all of the feeds and Alysia Marino assisted in the measurements. The modeling of the feeds was made possible by assistance and code from YRS Associates: Yahya Rahmat-Samii, Bill Imbriale, and Vic Galindo. Of particular note, YRS Associates derived the groove dimensions and feed shapes and computed the feed emissivity. This research was supported by the MAP Project under the NASA Office of Space Science. More information about MAP may be found on the World Wide Web.
Funding AgencyGrant Number
Subject Keywords:cosmic microwave background; instrumentation: miscellaneous
Issue or Number:2
Record Number:CaltechAUTHORS:20111101-143159282
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Official Citation:The MAP Satellite Feed Horns Chris Barnes et al. 2002 ApJS 143 567
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:27561
Deposited By: Ruth Sustaita
Deposited On:01 Nov 2011 21:51
Last Modified:09 Nov 2021 16:49

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