Surface Accuracy Improvement of the Yebes 40 Meter Radiotelescope Using Microwave Holography

Author

Lopez-Perez, Jose A. ; de Vicente Abad, Pablo ; Lopez-Fernandez, J.A. ; Tercero Martinez, Felix ; Barcia Cancio, Alberto ; Galocha Iraguen, Belen

Author_Institution

Centro Astron. de Yebes of Direccion Gen., Inst. Geografico Nac., Guadalajara, Spain

Volume

62

Issue

5

fYear

2014

fDate

May-14

Firstpage

2624

Lastpage

2633

Abstract

The surface improvement of the Centro Astronómico de Yebes (CAY) 40 m radiotelescope with the use of coherent (with-phase) microwave holography is shown. For this purpose, a dual channel Ku-band receiver in prime focus has been developed. It allows holography measurements with unmodulated beacons from geostationary satellites in the Clarke belt. Initial surface measurements revealed an accuracy of 485 μm amplitude-weighted RMS (WRMS) with respect to the best-fit paraboloid. After a few iterations of the measurement and surface adjustment cycle, the accuracy has been improved to 194 μm WRMS. This means an estimated aperture efficiency improvement from 2.6% to 38.2% at 86 GHz for a prime-focus receiver with an illumination equal to the one produced by the holography receiver test feed.

Keywords

microwave holography; microwave receivers; radiotelescopes; CAY radiotelescope; Centro Astronómico de Yebes radiotelescope; Clarke belt; WRMS; amplitude-weighted RMS; best-fit paraboloid; coherent microwave holography; dual channel Ku-band receiver; efficiency 2.6 percent to 38.2 percent; frequency 86 GHz; geostationary satellites; holography measurements; holography receiver test feed; prime-focus receiver; size 40 m; surface adjustment cycle; surface measurements; unmodulated beacons; Antenna measurements; Antenna radiation patterns; Apertures; Holography; Phase measurement; Receivers; Satellites; Holography; radio astronomy; receivers; reflector antennas; satellites;

fLanguage

English

Journal_Title

Antennas and Propagation, IEEE Transactions on

Publisher

ieee

ISSN

0018-926X

Type

jour

DOI

10.1109/TAP.2014.2307351

Filename

6746023