A research team led by Professor Sun-Kyung Kim at the Department of Applied Physics has developed a new metallic metamaterial film that prevents radar signal loss, even in extreme cold conditions

The safe navigation of autonomous vehicles, drones, and ships requires radar to accurately detect the relative location and speed of surrounding objects. Radar functions as the eyes of these autonomous systems, applying the high permeability of microwaves to detect nearby objects even amid adverse weather conditions. However, ice or frost can form on the radar surface when the temperature is low, causing signal loss and increasing the risk of accidents.

Professor Kim’s team has developed a film that, when applied to radar systems, ensures safe autonomous driving even in extreme environments. “Our metamaterial film allows 100 percent transmission of radio waves while exhibiting low electrical resistance,” explained Professor Kim. In recognition of its technological innovation, this research was published in May 2024 in Natural Communications (IF 16.6) under the title, “Microwave-transparent metallic metamaterials for autonomous driving safety.”

“Our film will set a new standard for autonomous driving.”
The metal heating film for radar systems needs to be transparent in the visible light range to ensure a clear view. Professor Kim’s team focused on achieving high transmittance in the microwave band using metamaterials. “There has been no previous research on transparent heating film in the microwave band, making it difficult to ensure the stability of autonomous driving under diverse climate conditions. This research was a challenge to improve the limitations of autonomous driving technology,” Professor Kim explained.

Metamaterials are artificially designed to exhibit desired dielectric properties at specific frequency ranges by structuring or patterning materials with well-known dielectric constants. The team of researchers developed a metal metamaterial film with over 70 percent of its surface covered by metal, yet fully transparent to radar waves.

The developed metamaterial film boasts world-class electrical resistance and can rapidly remove thick ice in temperatures below 20 degrees Celsius or lower. “The results indicate that radar systems can operate normally even in extreme cold,” said the lead professor. “This technology has the potential to become a crucial standard for implementing autonomous driving.”

Beyond autonomous driving, these findings can be applied in fields where microwave interference or resonance suppression is necessary. “The film can be used to protect sensitive equipment from radio waves or to block specific frequency bands,” explained Professor Kim. To broaden its applications, the research team plans to optimize the metamaterial structure for curved surfaces.