An ultra-wideband dielectrically loaded quad-ridged feed horn for radio astronomy

We present a broadband dielectrically loaded quad-ridged feed horn for illuminating reflector antennas. The feed horn combines a central dielectric spear with a corrugated skirt to achieve a near constant beam width over a 6:1 bandwidth from 0.7-4.2GHz. The feed accepts two linear polarizations which are differentially fed. We present the directivity of the feed measured in an anechoic chamber. The feed exhibits a directivity of 12dB±1.5 and a measured return loss of greater than 14dB across the frequency band.