TERMINAL ANTENNA FOR COMMUNICATIONS SYSTEMS

摘要

An inexpensive high gain antenna (11) for use on terminals communicating with low earth orbit (LEO) satellites (31, 33, 34 and 35) which include an elevation table (19) mounted for arcuate movement about a transverse axis (Xt) on an azimuth turntable (12) mounted for rotational movement about a central axis (Zg). A plurality of antenna elements (21) forming a phased array antenna are mounted on the top of the elevation table (19) and have a scan plane (30) which is parallel to and extends through the transverse axis (Xt) of the elevation table (19). The antenna (11) may be both mechanically and electrically scanned and is used to perform handoffs from one (LEO) satellite (31, 33, 34 and 35) to another by positioning the elevation table (19) of the antenna (11) with its boresight in a direction intermediate the two satellites (34, 35) and with the scan plane (30) of the antenna (11) passing through both satellites (34, 35). At the moment of handoff, the antenna beam (32) is electronically scanned from one satellite (31) to another (33) without any loss in data communication during the process.