Broadband feed designs of C-band for e-MERLIN

Abstract

As part of a major enhancement, designated e-MERLIN, to its MERLIN array of radio telescopes there is a need for new feed designs to cover 4GHz to 8GHz band, for large paraboloid dishes (up to 76 m * etres diameter) operating in both primefocus and cassegrain configurations. The requirement, in each case, for good return loss and constant beam width across an octave band, presents a set of difficult challenges. The feed designs for e-MERLIN are introduced here. The prototypes of the prime-focus feeds and the e-system corrugated horn feed have been designed, manufactured and tested, both in the laboratory and on the respective telescope. The complete corrugated horn for the Cambridge telescope will shortly be manufactured and measured.