Programme Element: ARTES 5.1
Reference nr.: 13.1TT.30
Planned Tender Issue: quarter 4, 2013
(*) Priority 2
Objective: To devise and implement a prediction tool able to assess the radiation pattern of antennas when mounted in physical environments (e.g. spacecraft top floor covered by thermal blankets) for which a deterministic geometrical description is not possible.
Targeted Improvements: 20 dB relaxation in payload filter rejection due to more accurate specifications, so lower-mass, volume and insertion loss filters.
Any serious analysis of the RF performance of an antenna in a realistic environment should take into account the effect of the surrounding structure on the antenna radiation pattern (e.g. reflection/diffraction contributions between the antenna and the structure).
This type of analysis is currently carried out by means of techniques such as Physical Optics, Geometrical Theory of Diffraction and Method of Moments. Unfortunately, for on-board antennas, the exact details of the spacecraft structural parts are never perfectly known, as most of the structure is usually covered with thermal blankets, making it practically impossible to recreate a geometrical model that reproduces the reality accurately enough. Therefore, a method should be devised and implemented in a prediction tool to take into account the non-deterministic geometrical features of the platform (i.e. statistical distribution of reflecting and diffracting properties of the objects) so that a non-deterministic antenna pattern can be derived. To consolidate the method, a characterisation of the electrical properties of the surface of the scattering objects can be used as input to the analysis. The overall embedded antenna pattern could be then expressed as a nominal average pattern plus an associated, direction-dependent, RMS pattern, to make sure that the predicted antenna RF performance is sufficiently conservative. Telecommunication missions are typical candidates in need for such a tool. A validation approach on a representative mock-up shall be proposed and implemented.
(*) Priority 2 activities will only be initiated on the explicit request of at least one delegation.