Wanted: tiny efficient military RF and microwave transmitters and receivers for sensors and communications

June 6, 2023
These RF and microwave components should exceed today's state of the art, and overcome long-established design limitations of the so-called Chu Limit.

ARLINGTON, Va. – U.S. military researchers are asking industry to develop small RF receivers, transmitters, and antennas for space-constrained RF and microwave applications in sensors and communications.

Officials of the U.S. Defense Advanced Research Projects Agency (DARPA) in Arlington, Va., issued a broad agency announcement on Friday (HR001123S0041) for the Macaroni project to develop tiny RF receivers and transmitters. Details of the project are secret.

These RF and microwave components not only should exceed today's state of the art, but also should seek to overcome long-established design limitations of the so-called Chu Limit that constrains the bandwidth of data that can be sent and received from small antennas.

Measurement and control of the electromagnetic spectrum is a key research area the U.S. Department of Defense (DOD), researchers point out. Spectrum dominance requires quick and efficient control of electromagnetic radiation from DC to the X-ray regime.

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The primary challenge of the Macaroni project involves receivers and transmitters that are much smaller in size than the wavelength of the sent and received electromagnetic radiation.

In classical antenna theory, the sensitivity-bandwidth product is fundamentally limited by the shape and size of the antenna. This performance degrades significantly as the antenna size becomes much smaller than the electromagnetic wavelength of operation.

Yet size-, weight-, and power- (SWaP)-constrained applications are driving efforts to move beyond traditional constraints, and develop efficient, electrically small antennas still presents a challenge.

Recent advances in quantum sensors, materials science, electromagnetic shielding, laser technology, resonators, cryogenic systems, and vacuum components have pushed the state of the art in sensing technologies. As these enabling technologies improve, a wider variety of protocols and methodologies become possible and previous notions of the performance limits require validation, researchers say.

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For transmitters, new insights in active antenna technology, control schemes, methods of impedance matching, and strategies for volume filling also present new opportunities. Recent efforts in piezoelectrics, magnetoelectrics, high-index materials, and multiferroic materials may be leveraged to improve the efficiency trade space for small antennas.

DARPA researchers are interested in any transmit and receive technologies that can achieve performance beyond the Chu limit that can incorporate electric and magnetic technologies -- especially in solutions that minimize the antenna size relative to the operating wavelength.

DARPA would like proposals that involve teaming arrangements within and among organizations with relevant expertise, research facilities, and capabilities in electrically small receivers and transmitters. Researchers say they believe proposals from multi-disciplinary teams will be necessary to achieve the Macaroni goals.

Disciplines spanning physics, electrical engineering, mechanical engineering, materials science, computer modeling, and systems engineering are expected.

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The Macaroni program is a 45-month three-phase program, starting next February, with an 18-month first phase, an 18-month second phase, and a nine-month third phase. The project emphasizes two technical areas: receivers and transmitters.

Receiver work will focus on receive sensitivity, link closure, and systems integration. Transmitter work will focus on transmitter strength, demonstrating a transmitter system, and system ruggedization.

Companies interested should request the classified addendum to the Macaroni project for additional technical details by filling out a request form, online at https://sam.gov/api/prod/opps/v3/opportunities/resources/files/620b30e4acc44e7a87f6a34f260b7e4e/download?&token=, and emailing it to [email protected].

Those interested in bidding should upload abstracts no later than 10 July 2023, and full proposals no later than 13 Sept. 2023 to the DARPA BAA website at https://baa.darpa.mil. Email questions or concerns to DARPA's Jonathan Hoffman at [email protected]. More information is online at https://sam.gov/opp/07e3eda5a19f4462be14e613d4712ad9/view.

About the Author

John Keller | Editor-in-Chief

John Keller is the Editor-in-Chief, Military & Aerospace Electronics Magazine--provides extensive coverage and analysis of enabling electronics and optoelectronic technologies in military, space and commercial aviation applications. John has been a member of the Military & Aerospace Electronics staff since 1989 and chief editor since 1995.

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