Study of Frequency Selective Systems. Part 1: Preliminary Investments on Shapes and Lattices; Software Developments. Part 2: Interfacing of Politecnico FSS Programs with Matra Reflector Antenna Software. Part 3: Application to MAC

摘要

The impact of frequency selective surfaces (FSS) on an offset Cassegrain satellite antenna comprising one solid main reflector, two dichroic subreflectors, and the feed clusters was assessed. Patch shapes and lattices were studied in order to develop FSS software. The FSS programs were interfaced with reflector antenna software. The complete package was applied to the MACS phase 2 TX antenna. Results show that the software can analyze any common FSS configuration with all necessary details: single or multigrid periodic structures (conductive patches) inserted in a sandwich of dielectric layers. The link with reflector antenna software allows an accurate prediction of overall antenna performance. Analysis reveals cross-polarization limitations in offset configuration, and phase shifts in dual-grid configuration with a wide range of incidence angles. This leads to a depointing of the beam radiated by the antenna. To compensate, two solutions appear feasible: either repoint the whole antenna, or vary the spacing between the two grids with respect to the incidence angles.