Status Report

The MAP Satellite Feed Horns

By SpaceRef Editor
January 13, 2003
Filed under , ,

Astrophysics, abstract

From: Robert S. Hill <>
Date: Fri, 10 Jan 2003 17:26:37 GMT (177kb)

The MAP Satellite Feed Horns

C. Barnes (1),
M. Limon (1,2),
L. Page (1),
C. Bennett (2),
S. Bradley (1),
M. Halpern (3),
G. Hinshaw (2),
N. Jarosik (1),
W. Jones (1),
A. Kogut (2),
S. Meyer (4),
O. Motrunich (1),
G. Tucker (5),
D. Wilkinson (1),
E. J. Wollack (2) ((1) Princeton, (2) NASA’s GSFC, (3) UBC, (4) U. Chicago, (5) Brown)

Comments: 9 pages with 7 figures, of which 2 are in low-resolution versions;
paper is available with higher quality figures at
this http URL

Journal-ref: ApJS, 143, 567 (2002)

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, Ka, 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 degrees 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.

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