Large aperture metal-mesh lenses for THz astronomy

In this paper we present preliminary results of a metal-mesh graded index Fresnel lens. The designed lens has a diameter of 300 mm, a focal length of 1050mm and operates from 70 to 300 GHz. It was not possible to directly scale the design of the previous lenses, so a Fresnel graded index was used. A new testing facility was developed and verified, which allowed us to show that the new lens matches the same performance of a traditional polyethylene lens. Lenses of this diameter are of interest in the astronomy instrumentation community.