Satellite relay system

DETAILED DESCRIPTION It is an object, therefore, of the present invention to overcome the disadvantages and limitations of a prior satellite relay system by providing a new and improved satellite relay system.
It is also an object of the present invention to provide a satellite relay system which utilizes a plurality of narrow spot beam antennas with sharp directivity for the TDMA communication system, and performs the switching between each earth station by a beam scanning system.
The above and other objects are attained by a satellite relay system comprising a power divider which is supplied a TDMA signal and distributes it to a plurality of output terminals, a plurality of variable phase shifters each connected to the output of said power divider, a plurality of power amplifiers each connected to the output of said phase shifters, a 2n-port directional coupler having n number of input terminals and n number of output terminals, and each input terminal being connected to the output of said power amplifiers, and each output of said 2n-port directional coupler is connected to a specific transmission antenna having sharp directivity and covering only a single specific earth station.
Said 2n-port directional coupler provides an output signal to each output terminal according to the amplitude and phase of the input signals on each input terminal.
The presence of the 2n-port directional coupler and the sharp directivity of antenna are important features of the present invention.
It should be appreciated that the switching or the beam scanning of a TDMA signal is substantially controlled by said phase shifters, which operate at a low signal level.