Dave has a very quick look impromptu look at the Australian Square Kilometre Array (SKA) Phase Array Feed Prototype receiver Photos: http://www.flickr.com/photos/eevblog/sets/72157636751123456/ Design of the Phase Array Feed: http://www.atnf.csiro.au/projects/mira/tech_session3_SH.pdf http://www.atnf.csiro.au/research/conferences/Parkes50th/RobertBraun.pdf
NOTE: This is most definitely not up to my usual standard for content or quality, so don't expect much, it is what it is.