2002/12/01 by C. Barnes, Chris Barnes, M. Limon +27 · 3 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Radio Astronomy Observations and Technology #Superconducting and THz Device Technology #astro-ph
paper · pdf · doi:10.1086/342833
published as Astrophys.J.Suppl. 143 (2002) 567 · 9 pages with 7 figures, of which 2 are in low-resolution versions; paper is available with higher quality figures at http://map.gsfc.nasa.gov/m_mm/tp_links.html
openalex publication_date 2002/12/01 · arxiv created 2003/01/10 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
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.