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Large RF Windows for High-Temperature Seekers


OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Hypersonics; Advanced Materials


The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.


OBJECTIVE: The objective for this effort is to mature window technologies for use in RF seeker systems for extreme hypersonic environments.  Specifically, the sponsoring organization  seeks to advance the technical and manufacturing maturity of novel materials for large form-factored RF transparent windows that can be conformally mounted in the nose section of a hypersonic vehicle (e.g.: doubly shaped).  This challenging mission environment demands technical solutions with specialized thermomechanical properties, structural designs, manufacturing optimizations, and RF performance across a wide range of operational temperatures.


DESCRIPTION: As hypersonic strike systems become more prolific across the DoD munitions community, there is an increasing need to develop, mature, and improve upon the various specialized sensors and associated apertures or windows necessary to strike ground mobile and maritime targets.  Conventional legacy sensors and associated apertures or windows do not survive through the extreme thermal environments associated with hypersonic weapons.  The art and science of specialized high-temperature seeker RF windows that are manufacturable at scale is still very immature, and this is especially true for large RF windows. This topic aims to address material science, mechanical design, manufacturability, and RF performance challenges towards dramatically increasing the TRL and MRL of large high-temp RF windows.


PHASE I: As this is a Direct-to-Phase-II (D2P2) topic, no Phase I awards will be made as a result of this topic. To qualify for this D2P2 topic, the Government expects the Offeror to demonstrate feasibility by means of a prior “Phase I-type” effort that does not constitute work undertaken as part of a prior SBIR/STTR funding agreement.

For this Direct-to-Phase-II topic, the Offeror is expected to have previously demonstrated competence in the design of high-temperature ceramics and/or ceramic matrix composites for RF windows.  Offerors should have demonstrated experience in high-temperature materials engineering, testing, and designing for manufacturability.


PHASE II: For this Direct-to-Phase-II topic, the proposer shall design, characterize, prototype, and test an advanced large-form-factor RF window for hypersonic strike applications.  Emphasis shall be placed on RF performance, ease of manufacturability, reliability and system safety despite the inhospitable environment, and follow-on production costs.  Six prototype large-form-factor RF windows will be delivered.  Testing of the prototypes shall include RF performance across the operational thermal profile and across the operational shock/vibration profile.  Testing shall also include weather particulate impact assessments.


PHASE III DUAL USE APPLICATIONS: Following successful completion of this Direct-to-Phase-II topic, AFRL and our transition partner will assess any remaining TRL or MRL gaps needed to ready this large-form-factor RF window design for integration with a DoD Prime contractor’s hypersonic seeker system and work to address those gaps via a Phase III contract or other mechanism.



  1. Properties of large scale ultra-high temperature ceramic matrix composites;
  2. D. Sciti, P. Galizia, T. Reimer, A. Schoberth, C.F. GutiƩrrez-Gonzalez, L. Silvestroni, A. Vinci, L. Zoli;
  3. Composites Part B: Engineering Volume 216, 01 Jul 2021, 108839;
  4. Dielectric and mechanical properties of hypersonic radome materials and metamaterial design: A review;
  5. T. Kenion, N. Yang, C. Xu;
  6. Journal of the European Ceramic Society, Volume 42, Issue 1, Jan 2022, Pages 1-17.;


KEYWORDS: Keywords: High-temp materials; hypersonics; RF seekers; seekers; manufacturability; CMC; RF windows; RF apertures.

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