N092-151 TITLE: Infrared-Transparent, Millimeter-Wave Bandpass, Missile Dome Design

TECHNOLOGY AREAS: Materials/Processes, Sensors, Weapons

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 3.5.b.(7) of the solicitation.

OBJECTIVE: The objective of this SBIR program is to develop infrared-transparent, millimeter-wave band pass coatings and apply them to missile domes and windows. The coated dome will transmit mid-wave infrared radiation and millimeter-wave radiation at a frequency in the Ka-band and provide shielding at out-of-band microwave and radio frequencies. Reflection of the Ka-bandpass frequency must be negligible.

DESCRIPTION: The future of fire-and-forget missiles with "lock-on after launch" capability has been advanced by merging diverse sensor outputs (i.e. multi-mode seekers).[1] Multi-mode seekers that merge infrared (IR) detection and millimeter-wave (MMW) radar have been successfully demonstrated.[2a,b,c] Innovative designs are needed for domes and windows with multi-band transparency and electromagnetic shielding.[3] The optical and mechanical properties of infrared-transparent materials are well known[4a,b,c], however conductive infrared-transparent coatings, which can provide the material for a MMW band pass structure, are still in a developmental stage.[5a,b] A lower-cost approach, utilizing a conductive infrared-transparent coating, is sought to replace IR-transparent radomes that employ an embedded metal grid to provide electrical conductivity.

PHASE I: The first several months of this SBIR program will focus on developing radome coatings and fabrication methods that satisfy the stated dual band transmission requirements. Such coatings must be applied in a manner that will survive the environment of a tactical missile. Demonstrations of flat windows composed of ALON(TM), spinel, zinc sulfide or other IR window material, with an infrared-transparent, MMW bandpass coating will be prepared. The flat windows must transmit >90% in the 3-5 micron IR region and MMW loss should be <0.5 dB at a specified frequency within the Ka-band. The design should provide the narrowest possible band pass around the designated frequency and the maximum possible (>20 dB) attenuation outside the band pass.

PHASE II: Year One ($500,000); The goal of Phase IIa is to optimize the optical and electromagnetic performance of the windows developed in Phase I. Testing will include measurement of the operational temperature range for the design, as well as rain and sand erosion tests. Results of the testing will be used to determine the most suitable dome design (e.g. a 150mm hemispheric dome).

Year Two ($500, 000); In Phase IIb the techniques to apply the selected coating to a full dome will be developed. The prototype dome will be tested to optimize optical and electromagnetic performance. Production capability for the prototype dome with midwave IR-transparency and a Ka-band bandpass filter will be established. The design will be extended to infrared-transparent flats for a W-band filter (instead of Ka-band)

PHASE III: Work with a Prime Contractor to qualify the coating and design for insertion into a new or existing system (e.g. Joint Air-to-Ground Missile, JAGM, Tomahawk, Small Diameter Bomb Increment II).

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Both infrared and millimeter-wave bandwidths are important in the communications industry. The advanced window design will be applicable to shielding and multi-mode communications

REFERENCES:
1. M Cannon, PEO Tactical Missiles, Sensor to Shooter Timeline Equation, http://www.dtic.mil/ndia/2004precision_strike/CANNONTimelineEquation.pdf, last accessed 7 April, 2005.

2. (a) New Eagle Eyes Dual-Mode Seeker Successfully Demonstrated, http://www.spacedaily.com/news/missiles-04c.html, last accessed 7 April, 2005.
(b) Raytheon successfully demonstrates Common Modular Missile tri-mode seeker, http://www.raytheon.com/newsroom/briefs/011303.html, last accessed 7 April, 2005.
(c) Joint Common Missile Seeker Successfully Tracks Tactical Target Vessel in Littoral Testing http://www.missilesandfirecontrol.com/our_news/pressreleases/05pressrelease/011905-JCM.htm

3. J. C. Kirsch, W.R. Lindberg, D. C. Harris, M. J. Adcock, T. P. Li, E. A. Welsh and R. D. Adkins, "Tri-Mode Seeker Dome Considerations" Proc. SPIE Vol. 5786, Window and Dome Technologies and Materials; Randal W. Tustison; Ed., 2005.

4. (a) D. C. Harris, Materials for Infrared Windows and Domes, SPIE Press, Bellingham WA, 1999.
(b) M. Stead and G. Simonis "Near millimeter wave characterization of dual mode materials", Applied Optics, 28(10) 1874-1875.
(c) C. I. Bright "Electromagnetic Shielding for Electro-Optical Windows and Domes", Proc. SPIE Vol. 2286, Window and Dome Technologies and Materials IV; Paul Klocek; Ed., 1994, 388-395.

5. (a) Linda F. Johnson, Mark B. Moran "Infrared transparent conductive oxides" Proc. SPIE Vol. 4375, Window and Dome Technologies and Materials VII; Randal W. Tustison; Ed., 2001, 289-299.
(b) D. H. Rapkine, G. A. Thomas, R. J. Cava, J. Kwo, S. A. Carter and J. M. Phillips, Band Gap Shift in a New Transparent Conductor http://flux.aps.org/meetings/BAPSMAR96/abs/S1730129.html, last accessed 7 April, 2005.

KEYWORDS: infrared dome; IR window; radome; millimeter-wave; bandpass filter; multi-mode seeker

** TOPIC AUTHOR (TPOC) **

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