Outcomes of a study undertaken by CSIRO on the six possible shaped beams for the Galaxy HS601C satellites are described. These satellites will provide C- and Ku-band communications to continental USA and neighbouring islands. Of especial concern in the study was the effect on performance of mutual coupling between the multi-mode horns in the feed arrays for the reflectors which generate the shaped beams. Mutual coupling influences the reflection coefficient at the horn inputs as well as the directivity of the shaped beam. After a brief description of the antenna geometry, methods used to analyse the antennas are outlined. Results are presented for possible antenna designs with and without mutual coupling in the feed array. We describe some techniques employed to optimize the array beamforming networks. Due to practical considerations it was possible to change only some of the beamforming network couplers and the impact of shaped beam design with a reduced set of couplers is discussed.
|Number of pages
|Journal of Electrical and Electronics Engineering, Australia
|Published - Sept 1992