Scientists have developed an extremely thin material that can protect electronic components by absorbing several varieties of electromagnetic radiation.
According to a Korean Institute of Materials Science (KIMS) team, the novel material absorbs virtually all electromagnetic radiation (EM) from three distinct spectra, including 5G/6G, WiFi, and the radar used in autonomous driving systems. While some similar materials can absorb the EM radiation from one of these spectra, this is the first material to work across all three simultaneously.
According to the scientists behind the potentially breakthrough material, modern electronics can be disrupted by emissions from other devices, resulting in spotty performance or even failure. Furthermore, many currently available shielding materials simply reflect away electromagnetic radiation instead of absorbing it, resulting in “secondary interference” issues. This situation has motivated materials scientists to find a simple and versatile solution capable of protecting a wide range of modern electronic devices from the ambient EM energy across multiple spectra generated by the Internet of Things (IoT).
“While conventional shielding materials struggle in the mmWave spectrum due to their reflective nature, this study introduces a novel EMI shielding film with ultralow reflection (<0.05 dB or 1.5%), ultrahigh absorption (>70 dB or 98.5%), and superior shielding (>70 dB or 99.99999%) across triple mmWave frequency bands with a thickness of 400 µm,” the study authors explain.
Combination of Composite Materials Absorbs Electromagnetic Radiation
Led by the study’s senior author, Dr. Byeongjin Park, and assisted by co-author and collaborator Dr. Sang Bok Lee from the Composites & Convergence Materials Research Division at the Korea Institute of Materials Science, the new study first looked at the limitations of current electromagnetic radiation-blocking materials used in commercial and industrial applications. This effort revealed that most of these conventional materials worked by reflecting rather than absorbing the EM waves. According to the study, most reflected around 90% of EM while absorbing around 10%. Furthermore, when materials displayed a higher absorption rate, that ability was confined to just one EM spectrum.
Park and Lee countered this limitation by exploring the use of multiple radiation-absorbing materials combined into one protective film. Their final formula involved combining a magnetic composite layer that had proven effective at one range of frequencies with a second layer of carbon nanotubes that complemented the other layer’s performance. The team also added a conductive patterned grid to enhance this ability.
Finally, the researchers created an ultra-thin polymer composite film and incorporated “conductive patterns” on its backside. This alteration allowed the team additional control over the propagation of electromagnetic waves. According to the study authors, this combination of materials and design resulted in a composite material that absorbed over 99% of electromagnetic radiation while reflecting almost none.
“By integrating a magnetic composite layer (MCL), a conductive patterned grid (CPG), and a double-walled carbon nanotube film (DWCNTF), specific resonant frequencies of electromagnetic waves are transmitted into the film with minimized reflection and trapped and dissipated between the CPG and the DWCNTF,” they explained.
Notably, the carbon nanotubes had a typical design. However, the MCL layer was created by altering the crystal structure of ferrite. This process allowed the scientists to effectively ‘program’ the material to absorb selected EM wavelengths. The team also found that the geometry of the composite material enhanced the ability to block electromagnetic radiation, resulting in an over 99% absorption rate.
“By adjusting the shape of the conductive pattern, electromagnetic wave reflection at specific frequencies can be dramatically reduced,” the press release announcing the research explains.
Along with its absorption performance, the material proved versatile and durable. According to the study authors, lab tests showed that their ultrathin composite material could be bent and still resume its original shape over 5,000 times without losing integrity or diminishing its electromagnetic radiation-absorbing performance.
Patented Material Could Find Several Applications
Since KIMS is part of the country’s Ministry of Science, the press release notes that the material has already been transferred to various domestic materials companies and is “currently being applied to actual communication devices and automobiles.”
The researchers have already patented the material in Korea. However, given the potential worldwide market for this type of electromagnetic radiation-absorbing solution, they are also applying for similar patents in the U.S., China, and other countries.
“This innovative approach presents a promising solution for effective mmWave EMI shielding materials, with implications for mobile communication, radar systems, and wireless gigabit communication,” they write.
The study “Absorption-Dominant Electromagnetic Interference (EMI) Shielding across Multiple mmWave Bands Using Conductive Patterned Magnetic Composite and Double-Walled Carbon Nanotube Film” was published in Advanced Functional Materials.
Christopher Plain is a Science Fiction and Fantasy novelist and Head Science Writer at The Debrief. Follow and connect with him on X, learn about his books at plainfiction.com, or email him directly at christopher@thedebrief.org.