TRANSMISSION IMPAIRMENT PARAMETERS IN MULTIPLE-BEAM SATELLITE COMMUNICATIONS SYSTEMS∗

This paper addresses transmission impairment mechanisms in multiple-beam satellite communications systems that use active phased arrays. The communications link and system aspects are assessed through measurements and analysis. Three link parameters that contribute to transmission impairment are investigated and their effects on the overall carrier-to-interference ratio are quantified. First are the intermodulation components that are generated at the non-linear amplifier outputs and contribute to well-formed interference in the array radiation pattern. Second is the bit-error ratio (BER) degradation due to the multi-carrier operation of the active array. Third is the co-channel interference caused by frequency re-use in the multiple-beam system