Fast Surrogate-Based Optimization of Wideband Quad-Ridge Flared Horn Feeds for SKA and ngVLA

Both the SKA and ngVLA radio telescopes (will) use shaped offset Gregorian reflector antennas, in the feed low configuration, with a variety of different feeds to cover their full operating bandwidth. It is foreseen that both systems will most likely employ variations of quad-ridge flared horns (QRFH) to cover receiver bands with about 3.5:1 bandwidth – possibly wider [1] , [2] . For both systems, the most important performance parameter is the receiving sensitivity, and it is critical that any feed horn employed in the telescope has a carefully controlled radiation pattern, which is specifically designed to maximize the receiving sensitivity over the entire operating bandwidth.