Design and measurements of dual-polarized wideband constant-beamwidth quadruple-ridged flared horn

A quad-ridged, flared horn achieving nearly constant beamwidth and excellent return loss over a 6-1 frequency bandwidth is presented. Radiation pattern measurements show excellent beamwidth stability from 2 to 12 GHz. Measured return loss is >; 10 dB over the entire band and >; 15 dB from 2.5 to 11 GHz. Using a custom physical optics code, system performance of a radio telescope is computed and predicted performance is average 70% aperture efficiency and 10 Kelvin of antenna noise temperature.