TECHNOLOGY AREAS: Air Platform, Sensors

ACQUISITION PROGRAM: JSF - Joint Strike Fighter Program; PMA-290

OBJECTIVE: Design and develop an aircraft antenna capable of operation at frequencies from 30 MHz to 2 GHz, without significant impact on aerodynamics, and designed to occupy the smallest practical surface area at the lowest weight practical.

DESCRIPTION: Currently available communications antennas for aircraft have several problems. Blade antennas are inherently resonant structures that are difficult to extend to wider bandwidths, they impact the flight characteristics of faster aircraft, and they may present an ice accumulation problem on some aircraft. Low-profile antennas generally are cavity-backed, requiring significant protrusion into the slipstream outside the aircraft body or significant hull penetration to accommodate the cavity, and the cavity is generally only optimal at one frequency. Additionally, the ever increasing number of antennas on aircraft are impacting the ability to find space for more antennas, requiring simultaneous use of antennas by several radio sets.

The need is for an antenna that does not cause significant aerodynamic drag and does not require structural penetration of the aircraft hull (fasteners and connector penetrations only), and at the same time provides vertically polarized coverage to the horizon at any frequency from 30 MHz to 2 GHz from several radio sets operating simultaneously. It is assumed that isolation of these radio sets will be handled by separate circuitry. The combined power levels from all connected radio sets could approach 100 Watts at 100% duty cycle in some applications. Primary constraints are weight and surface area consumed. Weight allowance is always at a premium on any aircraft. The surface area available is usually minimal at best. An antenna capable of communication with satellites at any azimuth angle and any elevation above the horizon is desired. These would likely benefit from circular polarization toward the sky and would be useful for GPS signals and various communications satellites. The use of advanced materials and concepts is encouraged, particularly the use of controlled impedance surfaces, artificial perfect magnetic conductor (PMC) materials and other meta-materials.

Applications are for communications systems on any aircraft. Current acquisition programs that could benefit from this project include helicopters, Unmanned Aerial Vehicle (UAV) aircraft, tactical fixed-wing aircraft and transport category aircraft.

PHASE I: Determine the technical feasibility of and concepts for candidate approaches likely to be able to satisfy the requirements. Conduct a computational analysis showing limits on performance for candidate approaches. Demonstrate the capability of the selected approach using computational and laboratory models. The use of a standard circular ground plane for all computations and measurements is highly recommended.

PHASE II: Complete the design selected in Phase I, fabricate a technology demonstration model or prototype, and show the performance of this model through laboratory measurements. Conduct demonstration of the prototype.

PHASE III: Finalize the design from Phase II and transition the technology to the fleet.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Technology may be useful on commercial aircraft.

REFERENCES:
1. Brewitt-Taylor, C.R., "Limitation On the Bandwidth of Artificial Perfect Magnetic Conductor Surfaces", Microwaves, Antennas & Propagation, IET, Vol 1 No 1 Feb 2007 pp255-260.

2. Werner, D.H. and Werner, P.L., "The Design Optimization of Miniature Low Profile Antennas Placed In Close Proximity to High-Impedance Surfaces", Antennas and Propagation Society International Symposium, 2003, June 2003, Vol 1 pp 157-160.

3. Yeo, J.; Mittra, R., "Bandwidth Enhancement of Multiband Antennas Using Frequency Selective Surfaces for Ground Planes", antennas and Propagation Society International Symposium, 2001, July 2001, Pol 4 pp 366-369.

4. Orton, R.S.; Seddon, N.J., "PMC As An Antenna Structural Component", Twelfth International Conference on Antennas and Propagation 2003 (ICAP 2003), March 2003, Vol 2 pp 599-602.

KEYWORDS: antennas; wide-bandwidth antennas; low profile antennas; conformal antennas; PMC materials; meta-materials

TPOC: (301)342-9167
2nd TPOC: (301)342-9162

** TOPIC AUTHOR (TPOC) **

DoD Notice:   Between November 13 and December 9, 2007, you may talk directly with the Topic Author(s) to ask technical questions about the topics. Their contact information is listed above. For reasons of competitive fairness, direct communication between proposers and topic authors is not allowed starting December 10, 2007, when DoD begins accepting proposals for this solicitation.

However, proposers may still submit written questions about solicitation topics through the DoD's SBIR/STTR Interactive Topic Information System (SITIS), in which the questioner and respondent remain anonymous and all questions and answers are posted electronically for general viewing until the solicitation closes. All proposers are advised to monitor SITIS (08.1 Q&A) during the solicitation period for questions and answers, and other significant information, relevant to the SBIR 08.1 topic under which they are proposing.

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