Research on high precision antenna for DATE5

Dome A 5m Terahertz Explorer (DATE5) is a proposed telescope to be deployed at Dome A, Antarctica to explore the excellent terahertz observation condition unique to the site. The telescope needs to realize and maintain an overall reflector surface accuracy of 10 microns rms and a blind pointing accuracy of 2 arcseconds under the extreme site conditions and unmanned operating mode. Two candidate antenna designs have been proposed, one of which is based on an all-CFRP reflector and slant-axis mount and the other based on aluminum panels on carbon fiber backup structures and altazimuth mount. Both aluminum and CFRP sandwich prototype panels have been fabricated and tested in a climate chamber. The aluminum panel shows desired surface accuracy under both room temperature and low temperatures down to -60°C. CFRP panels with different sandwich structures are fabricated and tested. All of them achieve a surface accuracy around 5 microns rms at room temperature, but their surface accuracy differs significantly when they are cooled, indicating the importance of panel structural design. The aluminum and CFRP panels are equipped with different type of anti-icing heaters, and their performances have been verified respectively. Finally, demonstration experiments on near-field holography are performed and a repeatibility accuracy of 3 microns rms is achieved.