Development of Virtualized Metamaterials That 'Don't Show Up on Radar'

[Image source=Yonhap News]

[Asia Economy Reporter Junho Hwang] Domestic researchers, in collaboration with overseas research teams, have succeeded in developing metamaterials with broadband stealth capabilities. It is expected to be utilized in stealth equipment undetectable by radar or sonar, as well as in soundproofing and sound absorption designs.

The Ministry of Science and ICT announced on the 14th that a research team led by Professor Namkyu Park of Seoul National University and Researcher Chunrae Jo, in collaboration with the Hong Kong University of Science and Technology, developed a "virtualized acoustic metamaterial" technology that can freely realize the physical properties of acoustic waves.

Development of Virtualized Metamaterials

A schematic diagram of a virtualized metamaterial connected to a microprocessor, microphone, and speaker. The microprocessor detects the incident signal (M) in real time and performs a convolution operation with the pre-designed physical property (Y) to generate the scattered wave (S).

Metamaterials refer to artificial structures designed to interact with light and sound waves in ways that natural materials cannot. They can be used to tailor the propagation of common waves such as electromagnetic waves and sound waves to achieve stealth functions or to control light for applications like invisibility cloaks, high-performance lenses, efficient compact antennas, and ultra-sensitive sensors. However, the properties of metamaterials are determined by the characteristics of the natural materials and structures used in their fabrication. This means it is difficult to realize all physical properties. In particular, there are significant constraints in controlling or designing responses to different frequencies.

The research team developed virtualized metamaterials that overcome these physical limitations of conventional metamaterials. They digitally implemented the material structures of existing metamaterials to realize multiple physical properties.

Virtualized Metamaterials Beyond Conventional Metamaterials

The virtualized metamaterials created by the research team simulate the polarization phenomena of natural materials using digital circuits and signal processing technology. As a result, without actual physical structures, they exhibit the physical properties of desired waves or characteristics that disperse frequencies. Polarization refers to the phenomenon where a medium acquires electromagnetic polarity under the influence of an electromagnetic field.

Notably, these virtualized metamaterials have the advantage of being able to design frequency dispersion characteristics according to needs. Through experiments, the researchers succeeded in controlling frequency dispersion properties such as resonance strength, resonance frequency, and bandwidth.

Researcher Chunrae Jo stated, "It is highly significant that we have developed the world's first metamaterial capable of controlling broadband frequencies," adding, "This enables broadband control of wave phenomena such as reflection and scattering of light or sound."

He further explained, "This can be applied to develop materials that evade radar or sonar systems that detect enemies by emitting multiple frequencies, or to implement soundproofing and sound absorption designs," clarifying, "This is not a technology that makes light transparent like an invisibility cloak." However, he added, "It should be possible to construct metasurface lenses that exhibit desired physical properties for various types of light."

Meanwhile, this research was conducted with support from the Ministry of Science and ICT's Global Frontier Project (Wave Energy Extreme Control Research Group), which is promoting core source technology acquisition and practical research in the field of electromagnetic and mechanical metamaterials. The research results were published online in Nature Communications on the 14th.