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The proliferation of antenna systems of state-of-the-art military aircraft has challenged major airframe manufacturers to provide additional outer surface platform space for antenna placement while still maintaining a flightworthy structure. The solution is to design antennas that can sustain severe structural load. The recently completed 'RF Multifunction Structural Aperture (MUSTRAP),' contract number F33615-97-2- 3807 performed by Northrop Grumman Corporation (NGC), El Segundo, California and TRW/ASD, Rancho Bernardo, San Diego, California, together with their DoD customer have met this challenge by conceiving the novel technology of Conformal Load-bearing Antenna Structures (CLAS). Under the Air Force Research Laboratory, Air Vehicles Directorate, Structures Division's leadership and direction, the MUSTRAP team have developed multifunction, broadband, structurally integrated, low cost antennas for communications, navigation, identification (CNI) and electronic warfare (EW) applications in the 0.03 to 2.0 GHz range. Two concepts, a fuselage and a vertical tail installation, were designed, analyzed, fabricated, and tested. The fuselage demonstration article was a load bearing multifunction (UHF/SATCOM) antenna 35 by 37 inch panel subjected to combined axial and shear loading, which replicated realistic flight conditions. Ultimate failure loads imposed on the panel were 1,800 pounds per inch axial loading and 600 pounds per inch shearing loading, after successfully withstanding a single lifetime (6,000 hours) of fatigue. Electrical performance was validated using anechoic chamber measurements. The vertical tail concept was a structural excitation multifunction (VHF/UHF) antenna element that can be tailored to fit in virtually any end cap vertical tail configuration. Designed to endure the severe acoustic environment associated with empennage noise sources, the end cap was successfully flight tested on NASA/Dryden's Systems Research Aircraft (SRA) to validate the structural and electrical performance. Highlights of the program are presented in the text.
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