N151-076 TITLE: Compact, Polarization Preserving Antennas for the 40-200 GHz Frequency Range

TECHNOLOGY AREAS: Sensors, Electronics, Space Platforms

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 section 5.4.c.(8) of the solicitation. 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: Build a high gain, low noise figure, rad-hard, dual polarization, electronically steered, multi-beam antenna array for the 40-200 GHz frequency range using a scalable subarray design.

DESCRIPTION: Capital ships and satellites often use dish antennas to produce antenna patterns with narrow main beams and highly suppressed side lobes. But then, only one direction can be studied at a time. From all but geostationary orbits, this severely limits the time any given spot on the earth can be observed and such orbits severely limit the total field of view. Replacing the dish with an electronically steered array capable of forming, say, 4 beams, would increase the observation time of each spot in the pattern by a factor of 4, allowing less intense signals to be received. A quasi-conformal geometry would allow the mechanical risk to the mission of a failed on-orbit deployment to be eliminated. The use of extreme bandwidths is both enabled and made desirable by the still low utilization of these high frequencies for communications. In the radiometry application, the intended signal is the black body emission from the earth's surface and atomic and molecular thermal emissions. Both polarizations are required for the data to be interpreted properly. The signals normally occur at power levels below -150 dBm, so antenna gain is definitely desirable from both power and beam pattern point of view. Frequency dependent onductor loss must be considered because of the high frequency and the ideal of flat antenna gain. Active thermal control may be desirable to stabilize the operating temperature and thus conductive loss and antenna gain, even if superconducting materials are not used in the fabrication. Because of the short wavelengths at these high frequencies, the individual antennas will be very miniature, especially at the antenna feed and in connecting to the beam forming module. Distributed feed points may also be helpful to consider. Whole wafer lithography fabrication techniques may be required. Proposals should identify the class of antenna element that will be developed, conductor and substrate materials, and fabrication method. Goals should be defined for main beam width, side lobe suppression, noise figure, and antenna power gain, and planned method for forming 4, 16, 64,.... (and so on) simultaneous beams. The Phase I base effort must provide confidence that the minimal 4 beam 5:1 array can be delivered by the end of the proposed Phase II effort.

PHASE I: Determine technical feasibility and document by simulation (using industry standard CAD tools) and preliminary experimentation that the required antenna elements and feed structures can be manufactured to the specifications detailed in the description. The Phase I option, if exercised, should continue development of the required subcomponents, including experimental exploration of which design variation has better yield. Phase II proposal (due at end of Phase I base) should include a discussion of notional packaging concerns for the space and maritime environments.

PHASE II: Phase II shall include several design/fabrication/test cycles leading to an increase in the accuracy with which the performance limiting factors for the arrays are known and how these parameters scale with the number of elements and beams formed. Document the stability of performance parameters achieved under heat load conditions corresponding to the more extreme case of solar illumination and deep space exposure alternation, regardless of whether active temperature control is proposed. Design and demonstrate a suitable radome for the demonstrated antenna.

PHASE III: Finalize development of an optimally scaled array incorporated into the design of a future earth observing satellite having a mission similar to that of WINDSAT or a future capital ship communications system.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Currently there are commercial collision avoidance radar applications in the 60 GHz range, and the 94 GHz range is being developed quickly. Moreover, short range communications, such as WiFi hot spots, can best be accomplished over portions of the spectrum with large atmospheric attenuation which allows each user (due to their 100's of meters physical separation) to utilize wide frequency bands without interfering with other users. This allows high data rate information to be successfully transmitted. While these applications are not as wideband as those requested in this SBIR, it is the technology for forming the feeds and matching networks that must be developed here, and that will directly transition to these commercial applications. By demonstrating wideband capability, narrower sub-bands will have been proven. There is also a commercial SatCom and wireless data transmission community.

REFERENCES:
1. Active Electronically Scanned Array. http://en.wikipedia.org/wiki/Active_electronically_scanned_array

2. Electronically Steered Phased Array Radar Antenna. http://www.google.com/patents/US4931803

3. Antenna Array Analysis with Custom Radiation Pattern. http://www.mathworks.com/help/phased/examples/antenna-array-analysis-with-custom-radiation-pattern.html

4. Micro-Coaxial Fed 18 to 110 GHz Planar Log-Periodic Antennas With RF Transitions. http://ieeexplore.ieee.org/Xplore/defdeny.jsp?url=http%3A%2F%2Fieeexplore.ieee.org%2Fstamp%2Fstamp.jsp%3Ftp%3D%26arnumber%3D6671405%26userType%3Dinst&denyReason=-134&arnumber=6671405&productsMatched=null&userType=inst

5. NIST antenna calibrations extended to 60-110 GHz. http://phys.org/news99323764.html

6. TowerJazz and UCSD Demonstrate First Silicon Wafer-Scale 110 GHz Phased Array Transmitter with Record Performance. http://www.jacobsschool.ucsd.edu/news/news_releases/release.sfe?id=1189

KEYWORDS: wideband antennas; electronically steered arrays; antenna patterns; array gain; earth observation; black body radiation

** TOPIC AUTHOR (TPOC) **

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