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Multiband Metasurface for Reduced Antenna Footprint and Jamming Mitigation


OBJECTIVE: Research and develop a multiple-band, electromagnetically-tailored"meta"surface to reduce overall antenna payload footprint and mitigate effects from unwanted RF signals. DESCRIPTION: Satellite antenna systems sometimes utilize telecommunications links which transmit/receive (T/R) through separate apertures to prevent co-site interference. This increases the footprint and weight necessary for an antenna payload. Furthermore, antenna location must be carefully chosen on the spacecraft to prevent degradation in performance due to this"self-interference". This topic seeks to develop an engineered surface that would allow operation of multiple RF bands through a single antenna aperture while maintaining performance under influence of unwanted signals. This would effectively allow multiple T/R antennas to reside in one physical location. Design benefits include reducing complexity, redundant support systems, weight and total footprint. The performance benefit is to mitigate effects from unwanted signalsboth intentional (jamming) and unintentional (interference)which can include receiver desensitization, signal masking, spoofing and degraded anti-jam capability. As a result of both, this also would allow satellite designers greater freedom in choosing antenna payload location, free up valuable spacecraft real estate, and enable robust small satellite antenna systems. Electromagnetically (EM)-tailored surfaces, also referred to as"frequency-selective surfaces"or"metasurfaces"in recent publications, offer a means to control the electromagnetic properties of an EM wave that permeates its surface. The primary functionality of this surface is to create frequency band stops or band passes; the frequencies affected are dependent on the geometry and design of the unit cell"s periodic surface. This effectively isolates one antenna from another. The U.S. Navy has researched the field of metasurfaces to create a gimbaled, multi-layered antenna system for their capital ships that can simultaneously operate in L, S, and X-bandsreducing the overall footprint and weight, but increasing its overall size in free space. The freedom to create this large system of arrays or reflectors in free space is not a practical design for space satellite systems, so an alternative solution is needed. The key characteristic of a multi-band metasurface is to allow transmission and/or reception of signals whose bandwidths do not overlap significantly, thereby reducing effects of co-site interference. Proper tailoring of the design should also inherently introduce some level of protection from intentional broadband jamming. It is required that this be a conformal solution that adds negligible size/weight/power and works symbiotically with the antenna structure, as opposed to a standalone technology or payload. Low-power active control over bands of operation is of interest, but passive solutions are encouraged as well. Proof of design scalability is of strong interest, as this would give rise to a modular toolkit for SATCOM and ISR payload developers. Proposal must address the manufacturing and survivability issues and in particular consider the harsh launch and operating environments that satellite systems undergo. Heavy modeling and simulation for initial investigation of design approaches is highly encouraged. PHASE I: Examine EM-tailored surface for AEHF comm with threshold of 44 GHz up-link along with 60 GHz sat-2-sat comm and an objective to hit up-link, cross link and 20 GHz down-link. Provide analysis demonstrating proof-of-concept of single aperture operation of multiple RF bands and material selection suitable for the space environment. Assess active tunability and control mechanisms (if applicable). PHASE II: Refine concept from Phase I and demonstrate critical performance via experiment. Testing to be done includes EM property characterization, mechanical property characterization, and suitability to the space environment (any orbit). Demonstrate un-degraded or improved operation in the presence of appropriate threats, i.e. an interference/ jamming source. PHASE III: Military App: Immunity/mitigation of negative effects of unwanted signals on military space-based antenna payloads. Allows for unprecedented antenna payload design freedom. Commercial App: Same application for commercial satellite communications antennas. REFERENCES: 1. Walton E., Lee E., Kohlgraf D., Pavlovicz R., Bruce G., Montgomery B.,"Compact Shipboard Antenna System For Simultaneous Communication With Three Separate Satellites,"OCEANS, 2005, Proceedings of MTS/IEEE, Vol. 2, pp. 1577-1580, September 2005. 2. Bahu, M.B., Taylor L.L"Tactical communication EMI/EMC co-site problems and solutions,"Tactical Communications Conference, 1994, Vol.1, May 1994. 3. Ueno K., et al.,"Characteristics of FSS for a Multiband Communication Satellite,"Antennas and Propagation Society International Symposium, 1991; AP-S Digest, Ontario, Canada, pp. 735-738, June 1991. 4. Wickenden D.K., et al.,"Demonstration of Multi-Band Frequency-Selective Surfaces Using Split-Ring Triangular Resonators,"2006 IEEE International Workshop on Antenna Technology Small Antennas and Novel Metamaterials, pp 96-99, March 2006. 5. Holloway C.L., et al.,"Characterization of a Metafilm/Metasurface,"IEEE Antennas and Propagation Society International Symposium, 2009, pp 1-3, June 2009.
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