Foil cap is outdated: new ultra-thin film absorbs 99% of 5G, 6G and Wi-Fi waves

South Korean scientists have developed a thin film that absorbs almost all electromagnetic waves in the three bands of 5G, 6G, and Wi-Fi.

The research team of Dr. Byungjin Park and Dr. Sangbok Lee from the Composites and Convergent Materials Research Department of the Korea Institute of Materials Science (KIMS) has developed the world’s first ultra-thin film composite material capable of absorbing more than 99% of electromagnetic waves in various frequency bands.

The material, which absorbs and shields electromagnetic waves, is less than 0.5 mm thick and features a low reflection coefficient (less than 1%) and a high absorption coefficient (over 99%) in three different bands).

The electromagnetic waves emitted by electronic components can cause interference that impairs the performance of other electronic devices in the vicinity. To prevent this, electromagnetic shields are used.

Absorbing electromagnetic waves is more effective at reducing interference than reflecting them back. However, conventional electromagnetic shielding materials reflect more than 90% of the waves, and the actual absorption is often only 10%. Materials with higher absorption ability are usually limited to a single frequency range.

To overcome these limitations, the research team has developed a composite material that can absorb electromagnetic waves in multiple frequency bands simultaneously. The technology virtually eliminates the problem of secondary interference. The material is also thin enough, flexible, strong, and able to retain its shape even after several thousand bends, making it suitable for use in phones and wearable devices.

The team synthesized the magnetic material by changing the crystal structure of ferrite. The researchers made an ultra-thin polymer composite film and added current-carrying patterns on the back of the film to control wave propagation. This can significantly reduce the reflection of electromagnetic waves at certain frequencies.

A thin film of carbon nanotubes with high shielding properties was applied to the back side to improve the useful property of the material.

The research team has completed the registration of a domestic patent and has also applied for patents in the US, China and other countries. In addition, the technology has been transferred to several Korean materials companies, and it is already being used in real-world communication devices and automobiles. The study was published in Advanced Functional Materials.

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