The impact of CCIR reference patterns on the design of Intelsat C-band contoured beam antenna systems

On the basis of existing sidelobe reference patterns for earth-station antennas and direct broadcast satellite antennas, CCIR and IWP 4/1 are currently discussing similar sidelobe reference envelopes for future fixed-satellite service antenna systems. The objective is a more efficient use of the geostationary arc and the radio-frequency spectrum. From an antenna design point of view, this imposes an additional performance constraint, and its impact on spacecraft antenna size, mass, and complexity has to be carefully investigated. After discussing the gain roll-off reference patterns, the authors consider the performance of the Intelsat VI Hemi/Zone antenna system and optimization with a global pattern constraint. It is found that the existing complex Intelsat VI Hemi/Zone antennas cannot meet the demands of gain roll-off reference envelopes currently under discussion by CCIR, even if the antenna is reoptimized for the additional global pattern constraint.<
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