Implementation of an Optimised Cassegrain System for Radio Telescopes
Abstract
We present the antenna design for a radio interferometer, the Arcminute Microkelvin Imager, together with its beam pattern measurement. Our aim was to develop a low-cost system with high aperture efficiency and low ground-spill across the frequency range 12-18GHz. We use a modified cassegrain system consisting of a commercially-available paraboloidal primary mirror with a diameter of 3.7m, and a shaped secondary mirror. The secondary mirror is oversized with respect to a ray-optics design and has a surface that is bent towards the primary near its outer edge using a square term for the shaping. The antennas are simple to manufacture and therefore their cost is low. The design increased the antenna gain by approximately 10 per cent compared to a normal Cassegrain system while still maintaining low contamination from ground-spill and using a simple design for the horn.
Cite
@article{arxiv.0712.0911,
title = {Implementation of an Optimised Cassegrain System for Radio Telescopes},
author = {C. M. Holler and R. E. Hills and M. E. Jones and K. Grainge and T. Kaneko},
journal= {arXiv preprint arXiv:0712.0911},
year = {2011}
}
Comments
4 pages, 7 figures, to be published in MNRAS