Ground station antenna for satellite communication systems

Claim 1

A ground station antenna for a satellite communications transmission system via a first satellite, which is aligned with its axis is the main beam direction at least approximately to the point determined by the position of the first satellite in geostationary orbit, characterized in that the radiation diagram of the antenna (A,A') has a first 3-dB-beam width of between 0.2° and 2° in a first plane (I), and said first satellite and other satellite are in said first plane and possesses a second 3-dB-beam width of between 2° and 20° in a second plane (II) which is at right angles to said first plane (I), and the ratio of the beam width of the first beam to the second 3-dB-beam being equal to or less than 0.25, and the alignment of the first plane corresponds approximately with the plane established by the antenna axis in the main beam direction and a tangent to the geostationary orbit at the intersection point with the antenna axis and said ground station antenna comprising four parabolic reflectors arranged in a straight line, and four adjustable phase shift devices each having first sides connected to a common source and having second sides connected to separate ones of said four parabolic reflectors for precise alignment of the antenna.