Air Force seeks to explore terahertz radio -- one of the last frontiers in military RF communications

Sept. 27, 2023
Frequencies at these high ranges are unable to propagate well because these tiny waves absorb into the atmosphere and humidity quickly.

THE MIL & AERO COMMENTARY – Enabling technologies for electronic warfare (EW) capabilities are advancing quickly, which makes it urgent for the U.S. military to develop secure wireless RF and microwave communications systems that are somewhat immune to enemy attempts to jam, disrupt, or intercept.

Towards this goal, U.S. Air Force researchers are asking industry to develop radio communications that operate in one of the most difficult parts of the RF spectrum -- frequencies approaching the never-before-achieved terahertz region, where state-of-the-art microprocessors, RF transmitters and receivers, and data conversion technologies so far have been unable to penetrate.

It's a tough proposition to explore these RF frequencies that operate at frequencies higher than 100 GHz. First, frequencies at these high ranges are unable to propagate well because these tiny waves absorb into the atmosphere and humidity so quickly. Recent attempts have been able to send RF energy only a few feet before evaporating into the air.

Still, the potential benefits are great. Since it's difficult to transmit and receive at such high frequencies, the probability of an enemy's ability to eavesdrop on them is essentially nil. Plus, their propagation characteristics make them steerable such that they can be limited only to the intended transmitters and receivers.

Related: Air Force approaches industry on five-year project to develop secure ultra-broadband radio communications

Potential benefits go beyond just point-to-point communications. RF energy at the terahertz level also holds promise for future medical sensors to detect skin cancers, and to enhance brain scans. Some experts say terahertz RF and microwave energy someday even might be able to detect odors.

The Air Force Research Laboratory Information Directorate in Rome, N.Y., have launched a research program that will take industry proposals until 2028 called the Ultra-Broadband Terahertz Radio Development project (FA8750-23-S-7009).

Radio frequencies above 100 GHz, commonly known as terahertz or sub-terahertz band, remain underused for communications, despite their potential to enable secure wideband applications for communications systems, Air Force researchers say.

Air Force researchers want to design, develop, and demonstrate an ultra-broadband radio that dynamically adjusts carrier frequency, output power, and data rate within the frequency range of interest -- above 100 GHz.

Related: Terahertz chip offers new applications in sensors, communications, and collision avoidance

Recent advances in material and device technology have enabled components and subsystems such as power amplifiers, low-noise amplifiers, frequency multipliers, and antenna array subsystems that operate above 100 GHz.

Over the past decade technology development has demonstrated wireless links at 140, 200, 240, 300 GHz and above, and the next technology challenge is to develop a compact end-to-end communications system that operates in sub-terahertz and terahertz bands.

Researchers want an ultra-broadband radio that dynamically adjusts carrier frequency, output power and data rate within 100 to 300 GHz using state-of-the-art modem design for fast flexible baseband that can support spreading bandwidth to 10 GHz and data rate of 1 megabit to 1 gigabit per second, as well as adapt to atmospheric conditions, link requirements, and the presence of interference. The system also should be able to form and shape the terahertz beams to control the signal’s presence in time and space.

Related: DARPA moves forward with two companies on second-phase project for secure radio communications technologies

This project should be worth about $10 million through 2028, and several contract awards are expected. For now, Air Force researchers are asking only for white papers, and those submitting promising white papers will be asked to submit formal proposals.

Companies interested in participating are being asked to email white papers no later than 15 Dec. 2023 for 2024 awards; by 20 Sept. 2024 for 2025 awards; by 19 Sept. 2025 for 2026 awards; by 18 Sept. 2026 for 2027 awards; and by 17 Sept. 2027 for 2028 awards.

Email white papers to the Air Force's Ngwe Thawdar at [email protected], with copies to Claire Parisi at [email protected] and to Peter Ricci at [email protected]. Email questions or concerns to the Air Force's Amber Buckley at [email protected].

Voice your opinion!

To join the conversation, and become an exclusive member of Military Aerospace, create an account today!