While debates over spectrum sharing between the commercial industry and the Department of Defense (DoD) have seemingly cooled for now, the Defense Advanced Research Projects Agency (DARPA) plans to transition its COmpact Front-end Filters at the ElEment-level (COFFEE) project from lab to field by next year.
Ultra-Compact Filters: A Key to Congestion Relief
The COFFEE team has developed „ultra-compact” radio frequency filters that integrate into advanced antenna arrays. These filters isolate or suppress specific signals, enabling DoD and commercial technologies to safely share the congested 2-18 GHz spectrum without interference, according to program manager Todd Bauer.
Cleaner Spectrum Use: The Goal of COFFEE
Bauer emphasized that the technology isn’t a universal solution but provides better isolation between adjacent frequency bands for a broad range of systems. „We want cleaner use of available spectrum,” Bauer stated, noting the technology allows for communication channels to operate adjacently without spectrum bleed-over.
Field Deployment by 2026: DoD Radars, Data Links, and 6G
The COFFEE program, which began lab testing in 2022, plans to deploy its filters for three different designs by „mid to late 2026,” targeting DoD advanced radars, DoD Common Data Link radios, and commercial-based 6G installations. If successful, the systems will operate on the same bands without interference.
Alleviating Spectrum Battles: A Potential Solution
This technology could ease tensions among lawmakers, defense officials, and the Federal Communications Commission (FCC) over spectrum access, particularly the 3.1-3.45 GHz and 7.4-8.4 GHz ranges. The DoD needs these ranges for satellite communications, radars, and navigation, while the commercial sector seeks them for civilian use.
Reconciliation Decision: No Impact on COFFEE
Recent legislation mandated that the 3.1-3.45 GHz and 7.4-8.4 GHz portions of the spectrum will remain under DoD control and will not be auctioned off. However, Bauer said this decision „really doesn’t” impact the COFFEE program. The team remains focused on wider range to prevent such spectrum battles from arising later on
A Forward-Looking Approach: Preparing for Future Needs
DARPA takes a forward-looking stance, anticipating the need for more bandwidth and spectrum in the future. The COFFEE program’s exploration of the 2-18 GHz range aims to provide a technology solution for higher frequencies once both commercial and DoD entities operate there.
