Elliptical aperture offset Tx-Rx antenna system

An elliptical aperture antenna of 2:1 aspect ratio and equivalent area less than a 1.2-m circular aperture, with RF performance that meets FCC specifications, has been developed. In order to meet FCC requirements, the major axis (with the narrower bandwidth) of the antenna must be aligned parallel to the plane of the geostationary arc. Radiation in the out-of-plane direction (north-south) is not restricted by FCC rules, as there are no satellites in this direction. An X-Y positioner (similar to a polar mount) is used to provide this alignment capability. A special feed design is used to effectively illuminate the noncircular aperture. Test results, both primary and secondary, are shown and illustrate feedhorn primary patterns at 11.95 GHz (receive) and 14.25 GHz (transmit), respectively. All edge tapers are between -10.5 and -12.5 dB for the major axis at 30 degrees and the minor axis at 60 degrees .<>