Ultra-thin film capable of absorbing multi-band electromagnetic waves has been successfully developed

Concept diagram of the latest electromagnetic wave absorption and shielding materials. Image source: Korea Institute of Materials Science

Scientists at the Korea Institute of Materials Science have developed a composite ultra-thin film that can absorb more than 99% of electromagnetic waves from different frequency bands such as 5G, 6G, WiFi, and autonomous driving vehicle radars, and is expected to improve the reliability of wireless communications. The relevant paper was published in the latest issue of Advanced Functional Materials.

Electromagnetic waves emitted by electronic components can cause the performance of other nearby electronic devices to deteriorate. To prevent this from happening, electromagnetic shielding materials came into being. Traditional electromagnetic shielding materials mostly use reflection methods, which can reflect more than 90% of electromagnetic waves, and the actual absorbance is only about 10%. Materials with higher absorbance can often only absorb electromagnetic waves within a single frequency band.

To break this dilemma, the research team developed this composite material. It exhibits a low reflectivity of less than 1% and a high absorbance of more than 99% in three different frequency bands, and its thickness is less than 0.5 mm. In addition, the latest ultra-thin film is also soft and durable, and can maintain its shape even after being folded and unfolded thousands of times, making it very suitable for fields such as rollable mobile phones and wearable devices.

This study synthesized a magnetic material that selectively absorbs electromagnetic waves by changing the crystal structure of ferrite. On this basis, a conductive pattern was added to the back of this ultra-thin polymer composite film to control the propagation of electromagnetic waves. By cleverly adjusting the shape of the conductive pattern, the ultra-thin film can significantly reduce the reflection of electromagnetic waves at specific frequencies. In addition, a carbon nanotube film with high shielding performance is applied to the back of the ultra-thin film to further enhance the material's electromagnetic wave shielding ability.