Fabrication and electromagnetic characterization of novel self-metallized thin films
Unique, self-metallized films were investigated for deployable reflector antenna applications at L-band. Polyamic acid resins or soluble polyimides were doped with metal complexes, cast into films, and thermally cured. Each resulting film had a metallic layer on one side, adhering unfailingly to the polymer. Metallization was successful for silver or palladium in 3,3',4,4'-benzophenonetetracarboxylic acid dianhydride (BTDA) and 4,4'- oxydianiline and for gold in BTDA and 2,2-bis[4-(4- aminophenoxy)phenyl]hexafluoropropane (4-BDAF) or the space durable polyimide, 2,2-bis(3,4-dicarboxyphenyl)- hexafluoropropane dianhydride and 4-BDAF (LaRCCP1). Reflectivity, transmissivity, and emissivity were determined, using an HP 8510 Vector Network Analyzer, to within 0.001 precision and accuracy. A custom-made test fixture/positioner, a thru-reflect-line calibration, and calculated reflection coefficients were used. The Ag film proved most suitable for further study, with 0.9957 reflectivity and 0.0042 emissivity. The Pd films were 0.89 reflective and 0.11 emissive; both Au films tested entirely transmissive. Transmission and scanning electron micrographs, S-parameters, and power coefficients are shown.
Using inflatable antennas for portable satellite-based personal communications systems
Satellite-based personal communications systems (SPCS) use the satellite network to connect mobile personnel on the ground via a central support network in both military and disaster management situations. To maintain portability these systems require lightweight equipment that is quickly and easily deployed and operated in a variety of environments. Parabolic dish antennas provide the high gain required for direct satellite communication but their size and weight severely limit portability. The parabolic reflector contributes the greatest percentage of the weight and size of high gain antennas and as such the aim is to replace the reflector dish and feed system with a lightweight, stowable alternative without sacrificing performance.
Mobile communications satellite antenna flight experiment definition
Abstract There are classes of application that collectively require a variety of different types of large-aperture space antennas. Fortunately, there are a number of different deployable antenna concepts that have tremendous potential for such applications. However, these concepts vary in maturity from flight-proven designs to extremely innovative configuration definitions. But these promising concepts lack sufficient demonstrations of maturity to be seriously considered in the large size range for immediate application. The reason for this situation is an extremely limited space flight data base in addition to the technical limitations and great costs associated with meaningful ground testing of large, flexible, precision space structures. The user community of such structures, especially the commercial organizations interested in providing a Mobile Communications Satellite (MSAT) on a profit-making basis, will require significant demonstrations of technology readiness prior to application commitment. Such demonstrations will probably be based on a combination of extensive ground testing and subsequent space flight experiments. The Communications Division of the National Aeronautics and Space Administration (NASA) Office of Space Science and Applications sponsored a study at the Jet Propulsion Laboratory (JPL) to determine the technical feasibility and cost of a Shuttle-based flight experiment specifically intended for the MSAT commercial user community. The experiment will include demonstrations of technology in the areas of radio frequency (RF), sensing and control, and structures. This paper summarizes the results of the structural subsystem study. These results include experiment objective and technical approach, experiment structural description, structure/environment interactions, structural characterization, thermal characterization, structural measurement system, and experiment functional description.