The proposed development objectives is to synthesize previous investigations as well as developing new processes/technologies to fabricate a sunshield that can fulfill today?s and future market needs. Indeed, over the past 2-3 years MDA has worked on at least 4 antenna programs in which the sunshield technology available (essentially germanium coated Kapton) was not acceptable from a RF standpoint and/or from an ESD standpoint.
Aside from resolving the RF and ESD concerns, another portion of this development program is to identify and incorporate other potential improvements to sunshields (such as making the outside surface optically diffuse or having a low internal emissivity) in order to meet the current and forecasted market needs.
In short, the objective of the proposed R&D is to investigate potential material and processes available, select and test the best combination of technologies for the sunshield application and to bring the selected technologies to being commercially available within the next 5 years (scaling-up for production, completion of optimization/characterization, final qualification for flight usage, etc.).
The main function of a sunshield is to maintain the antenna within an acceptable temperature range, in order to limit the performance degradation due to thermal effects. For example, a reflector typically needs to be maintained between ?150C and + 140C to limit the performance degradations due to the thermal distortions. The thermal characteristics of the sunshields are therefore of prime importance, but other properties are also important. Obviously, the sunshield must be RF transparent at the antenna operating frequency. It must be lightweight and its electrical conductivity must be sufficient to suppress Electro-Static Discharge (ESD) events. For many applications, it should be also PIM free (i.e. shall not generate Passive Intermodulation).
Antenna suppliers worldwide are facing more and more situations in which the current sunshield technology is no longer adequate (more stringent RF requirements, higher frequencies, increasing awareness of ESD risks, etc.). MDA believes it can be bring significant improvements to many sunshield properties and develop a far superior sunshield.
In order to achieve a new and improved sunshield, 5 main aspects will be investigated separately. The most-promising technologies will then be combined to design a complete advanced sunshield.
It is possible that the best combination depends on some of the end-user requirements (for example, the best combination at lower frequencies like L-Band might not be the same as at higher frequencies like Ku-band and above).
The best combination also will depend on the result of the investigation carried in this R&D.
At this point, Tasks 1, 2, 3 and 4a are completed. The final samples have been procured and MDA is now in the testing phase. We expect to have the TRB in September and program closure the following month.
The Final presentation is to take place on the 19 November 2007.