Need to avoid those pesky radar guns?
Remember Predator in the jungle?
A new meta-material has been designed to efficiently absorb the radar energy that strikes it. Researchers created small semicircles filled with liquid-metal containing a gap, creating lossy resonant cavities based on the inductance of the ring and capacitance of the gap.
A New Application of Meta-Materials
Meta-materials are generally mechanical creations of nano-scale structures that possess unique electromagnetic properties. In this case, a liquid conductor is required in the ring space—the researchers chose galinstan, a metal alloy which is liquid at room temperature and less toxic than mercury.
To keep the liquid metal in place, a metal sheet with the interstitial liquid is sandwiched between silicone sheets.
The researchers, Liang Dong and Jiming Song at Iowa State University, found that as the resulting material was stretched and wrapped it would shift the tuning and hence the frequencies that would be attenuated.
Wrapping also provided for easy directional attenuation, since it's effective in any direction it faces.
The rings have a 2.5 millimeter outer radius and a width of half a millimeter. The gaps are 1 millimeter. This current design shows a 75 percent suppression between 8 and 10 gigahertz, which is X-band radar.
Different geometries of the ring structure should allow many other electromagnetic regions of effectiveness. Going smaller is doable, but as one goes smaller the cost and difficulty of fabrication increases.
The team’s future aspirations are to reach the same result in the visible light region of the electromagnetic spectrum and hopefully even the infrared. If that's achieved, then we'll have something pretty interesting to wear.
For more information, visit the Iowa State University college of engineering website.