ARLINGTON, Va., 16 June 2010. Signals intelligence experts at the U.S. Defense Advanced Research Projects Agency (DARPA) in Arlington, Va., are asking industry to develop new kinds of antenna elements to aid in signals intelligence on small platforms through volumetric interferometry.

DARPA issued a broad agency announcement Tuesday (DARPA-BAA-10-66) for the Antenna Element for Volumetric Interferometry (AEVI) program to develop new kinds of antenna elements for volumetric interferometry to help determine the locations of radar emitters and other RF emitters by determining the angle of arrival of their signals.

This technique is particularly difficult on small, space-constrained platforms because there is not enough area in which to space antenna elements for accurate measurements. Instead, DARPA wants to use volumetric interferometry, rather than traditional linear interferometry, because the volumetric technique does not take as much space for its antenna elements.

Volumetric interferometers will require significantly fewer antenna elements than analogous linear interferometer architectures, which would make precision interferometry for signals intelligence feasible for size-, weight-, and power-constrained platforms, DARPA officials say.

Since interferometers use the precision measurement of phase to extract the angle of arrival of RF signals, each antenna element must have not only a wide field of view, but also have well-behaved amplitude and phase response.

DARPA wants revolutionary antenna element only design ideas that would enable volumetric interferometry. Agency officials caution that they only are interested in antenna elements -- not other direction-finding components, modules, system architectures, or algorithms.

In addition to wide field of view and a well-behaved linear phase response, the antenna element should be capable of achieving a fmax:fmin ratio of at least 3:1 in the 2-18 GHz frequency band; the RF signals of interest could be of any common polarization.

The AEVI antenna element also should be able to accommodate two orthogonal polarizations, yet one antenna that meets all the AEVI requirements is not currently available. Through AEVI, DARPA wants one antenna element with characteristics that today are only separately achievable with a disparate group of antenna types.

Companies interested must respond no later than 29 July 2010. For questions or concerns contact DARPA's Ronald Esman by e-mail at DARPA-BAA-10-66@darpa.mil, or by post to DARPA-BAA-10-66 Coordinator, DARPA/MTO, ATTN: DARPA-BAA-10-66, 3701 North Fairfax Dr., Arlington, VA 22203-1714.

More information is online at https://www.fbo.gov/spg/ODA/DARPA/CMO/DARPA-BAA-10-66/listing.html.