Satellite communication system using rf power sharing for multiple feeds or beams in downlinks

Abstract

A satellite communication system includes at least one spacecraft in geosynchronous orbit for providing a plurality of beams on the surface of the earth, and a plurality of ground stations individual ones of which are located in one of the beams for transmitting uplink signals to the spacecraft. The spacecraft has a plurality of receivers for receiving a plurality of the uplinked signals from ground stations, a frequency translator for translating the received uplink signals to a transmission frequency of a plurality of downlink signals, and a plurality of transmitters for transmitting the plurality of downlink signals within the same beams as the corresponding uplink signals. Each transmitter includes a combiner for combining together a plurality of frequency translated signals and a power amplifier, such as a TWTA, for amplifying the combined plurality of frequency translated signals. An analysis is performed of how many transponder channels can be combined and power amplified in a single TWTA, or multiple paralleled TWTAs, and a determination is then made as to which feeds and/or beams have low data traffic and low required downlink power that makes then suitable candidates for combining their feeds and/or beams into a linearly driven TWTA(s). A reverse output multiplexer is used to separate the combined feeds and/or beams to the separate individual downlinks after the RF power amplification.