An apparatus for an antenna system comprising one or more blades for splitting the electromagnetic field received by an antenna into a plurality of sections corresponding to separate beams and redirecting said plurality of sections for detection by a plurality of detectors. The apparatus may comprise a plurality of blades for splitting the field into successively smaller and smaller portions. The plurality of detectors can be positioned outside the focal region of the antenna system. The apparatus may further comprise focusing means for focusing the sections of the field onto another blade or a detector. There is also provided an antenna system comprising a plurality of feed horns for producing a plurality of beams; and a plurality of elements for redirecting said beams towards a focal region of the antenna system so as to form a group of closely packed beams for transmission by the antenna system.