Multibeam antenna concepts for global communications

The paper presents the results of an analytical study of the RF and mechanical characteristics of various spacecraft antenna concepts considered for the post Intelsat V operation. Each concept uses the same reconfigurable antenna for Atlantic and Indian Ocean regions and provides a minimum of six shaped beams using the same spectrum. Three concepts are considered: (1) the B6' concept which requires four dual zone beams, two dual polarized hemibeams and dual polarized global beams; (2) the B6 concept which uses overlapping dual polarizations for each coverage area, but otherwise is similar to the B6' concept; and (3) the B7 concept which defines four zone beams for one polarization and two hemibeams for the orthogonal polarization. It is found that the required RF characteristics can be achieved with any of the three concepts.