Ground-based satellite communications nulling antenna

摘要

A ground-based antenna for use with a satellite communications (SATCOM) system that reduces interference from geosynchronous earth orbit (GEO) satellites. Because GEO satellites that provide coverage of the continental United States (CONUS) are uniformly separated along an equatorial arc around the earth, the GEO satellites are approximately uniformly separated in sine space when viewed from a ground terminal located within CONUS over typical communications frequency bands, such as the Ka band (29-39 GHz) and the Ku band (10-15 GHz). The invention can reduce interference by providing an uniformly illuminated rectangular aperture, in which the horizontal dimension is chosen so when the aperture is normal to a transmission axis between the antenna and the Nth satellite of a SATCOM systems, the nulls of the antenna radiation pattern align with the N±1, N±2, N±3, . . . satellites. Additionally, the uniformly illuminated rectangular aperture provides the highest illumination efficiency, which has a distribution of sin(x)/x. The aperture may be rotated 45 degrees about transmission axis so that the radiation pattern, along the diagonal of the aperture, which falls off as [sin(x)/x)]<2, meets or exceeds the regulatory limits.