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The sidelobe radiation associated wi th earth station antennas for satellite communication is rapidly becoming a critical design parameter. The efficiency of both frequency and orbi t uti l isation can be improved by control of the sidelobe response of the earth station antenna and, consequently, a reduction in the interference with neighbouring systems.It has been shown, (1,2), that this sidelobe response depends on several factors each requiring careful attention in the design phase. One of the least characterised of these factors is the scattering associated with the subreflector or feed support structure, particularly when this is of lattice construction. A measurement programme has been undertaken aimed at comparing the scattering associated with different types of support strut configurations which are commonly employed in large earth station antennas.

Demands for increased channel capacity in future communication satellite systems coupled with basic limitations in terms of satellite power and frequency spectrum will lead to requirements for advanced multiple‐beam antenna systems with frequency re‐use capability. This paper describes the results of a study of multiple‐beam antenna systems suitable for an advanced European business services satellite. Initially, background work is described which serves to define the overall system, analyse the link performance and specify the antenna requirements. A generalized parametric study of the capabilities of a model antenna is discussed to set the bounds of feasibility, as it was appreciated that some specification targets might prove impossible to attain. In parallel, a comparative survey of a wide range of antenna types is presented to determine the most promising configurations. Based on these two outputs, candidate antenna configurations are analysed in detail to predict accurately the capability of the more promising antenna types to meet the range of performance objectives. Finally, detailed electrical design studies are performed for specific example missions.

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