A meta-skin capable of shielding objects from radar has been developed by a team of researchers from Iowa State University. This innovation could pave the way to effective invisibility cloaks in the near future, scientists said.
This meta-skin, composed of rows of liquid metal devices, is capable of bending and stretching, and can be tuned to desired frequencies. The rings act as inductors, and the spaces between them behave like electronic capacitors. By changing the space between these units, it becomes possible to "tune" the material to suppress a particular frequency of radar signal.
Metamaterials like the newly-developed skin are capable of manipulating electromagnetic waves in a manner unlike natural substances. Bending and stretching the new material allows the skin to greatly reduce the signature of radar waves intercepting it.
This action is significantly different than stealth technology, which only reduces the amplitude of radar signals being sent back to a radar system. The meta-skin is capable of reducing an incoming signal by about 75 percent in the range of 8 to 10 GHz, researchers determined.
The meta-skin is composed of a series of split ring electric resonators, filled with the liquid metal alloy galinstan, which is placed inside a matrix of silicone. Each ring is 2.5 millimeters in radius and just 0.5 millimeters thick. The metal that makes up the core of these rings is far less toxic than mercury, and is a liquid at room temperature.
Future research will examine how similar technology could be used to create metamaterials, which could have the same effect on other frequencies of electromagnetic radiation, including visible light.
"The long-term goal is to shrink the size of these devices. Then hopefully we can do this with higher-frequency electromagnetic waves such as visible or infrared light. While that would require advanced nanomanufacturing technologies and appropriate structural modifications, we think this study proves the concept of frequency tuning and broadening, and multidirectional wave suppression with skin-type metamaterials," Liang Dong of Iowa State University said.
This new development could have a wide range of uses, including electromagnetic shielding and frequency tuning. A version of the new metamaterial could, one day, even be used to coat military vehicles in a new generation of stealth vehicles.
Development of the new meta-skin was profiled in the journal Scientific Reports.