Developing Wideband RF Systems That Can Withstand Electromagnetic Interference

Photo: DARPA

Scientists from the Department of Defense (DoD) are working to design a communication system that can operate despite increasingly congested airwaves. As the electromagnetic spectrum becomes ever more crowded with signals, engineers must work to fight against interference to ensure their messages get through. That’s where the WARP program comes in.

Known officially as the Wideband Adaptive RF Protection Program (or WARP for short), this initiative hopes to improve upon existing protections available for wideband receivers and take them to the next level of security. Researchers intend to develop adaptive filters for wideband, as well as analog signal cancellers. These signal cancellers will possess the power to cancel out externally generated interference signals. This will help prevent important communications being jammed by outside forces.

“Protecting our wideband digital radios from interference and jamming in the unpredictable EM environment is critical to our defense capabilities, and has prompted the exploration of wideband tunable circuit architectures to support cognitive radio technology. Unlike narrowband radios that rely on switching between pre-planned filtering and narrowband signal cancellation, today’s wideband radios lack the RF front-ends that could help mitigate harmful signals before they reach the sensitive receiver electronics.”

Dr. Timothy Hancock, DARPA Program Manager


Additionally, WARP will work to reduce internally generated interference signals to reduce saturation in wideband digital radios. Internally generated interference can come from the device itself, leading to unexpected saturation that can impede communication. Devices experience saturation when a signal is received that is outside the dynamic range of the receiver. The dynamic range indicates different levels of weak to strong signals that the receiver is capable of handling.

In order to combat these issues, including outside interference or jamming from hostile sources, engineers have constructed the target WARP components with very specific capabilities. They will possess the ability not only to sense the presence of an electromagnetic environment, but they will be able to use adaptive hardware to adjust accordingly.

When it comes to external interference, engineers are investigating the potential of tunable filters for wideband. These filters will be able to sense the environment and adapt accordingly to the electromagnetic activity occurring around them. At the same time, the filters will not negatively impact bandwidth or signal sensitivity. To achieve this, researchers will study unique filter architectures and determine which options are best for the project.

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