6G and terahertz waves breakthrough

An innovative Electromagnetic wave absorber enhances terahertz technology for future 6G and terahertz waves

Sixth-generation, or 6G, cellular networks are the next step in wireless communication, and electromagnetic terahertz waves are seen as crucial to its development. However, terahertz waves, with their higher frequency and shorter wavelength, are subject to greater interference from electromagnetic noise, making clear and secure transmission a challenge. The world of wireless communications is on the brink of a major leap forward. With 6G promising blazing speeds and near-zero latency, the future of connectivity is closer than ever. However, harnessing terahertz waves, which could deliver these unmatched data rates, haves been hampered by interference issues. A team of researchers has now turned the tide with a revolutionary electromagnetic absorber.

With 6G available, we would have the potential to download entire movies in seconds and stream high-definition virtual reality content seamlessly. Terahertz waves, situated between microwaves and infrared on the spectrum, offer tremendous data-carrying capacity. Yet, their extremely short wavelengths make them prone to disruptive electromagnetic interference. This sensitivity has long been a stumbling block for those hoping to deploy ultra-fast, reliable 6G networks. Researchers from the University of Tokyo, as part of a multi-institution team, have now created an electromagnetic wave absorber for waves between 0.1–1 terahertz (THz). This greatly expands the range of the terahertz frequency which could be commercially used in the future. The ultrathin film is inexpensive, environmentally friendly and can be used outdoors, as it is resistant to heat, water, light and organic solvents. The key lies in an ultra-thin film made from lambda-trititanium-pentoxide (λ‑Ti₃O₅). This material efficiently absorbs unwanted signals across a wide range, from 0.1 to 1 terahertz, making it possible to mitigate the interference which once plagued high-frequency transmissions.

If you have access to a 5G network, you'll probably have noticed a dramatic difference compared to the more widely available 4G. Its low latency (the time it takes for a signal to bounce from its source to a receiver and back) means lower lag times, which is great for gamers, while download speeds of up to 20 gigabits per second (compared to 0.1 gigabits per second) and potentially 1,000 times greater data capacity opens up opportunities for smart homes and smart cities. But this isn't the end of the road for wireless cellular technology, and developers have already been looking toward the next step—6G. Professor Shin-ichi Ohkoshi from the University of Tokyo explains, “When a terahertz wave passes through this material, it generates an alternating current in the conductive layer, which dissipates the energy and reduces interference. This significantly improves the signal quality.” Such advancements are crucial, as they could pave the way for the robust 6G networks which industry leaders, including organizations like the IEEE, have been eagerly anticipating. Terahertz waves are predicted to serve as carriers for the upcoming sixth-generation networks. Recent reports on tests with terahertz waves showed data transmission speeds of up to 240 gigabits per second. However, the challenge is not only to further improve speed, latency and data capacity, but to also prevent interference and reduce noise to ensure a secure and clear signal. What makes this absorber even more exciting is its practical design. With a thickness of just 48 micrometers, less than half the width of a human hair, it is not only incredibly efficient but also easily integrated into compact devices. Moreover, the absorber is economical to produce, thanks to the abundance of titanium, and it boasts impressive durability. It resists heat, water, organic solvents and even intense light, meaning it can perform reliably in harsh outdoor conditions.

That's where electromagnetic wave absorbers come in. They can inhibit the transmission or reflection of electromagnetic waves and when placed on the covers of transmitters and antennas, help to enhance communication precision. This remind of a tech exhibition where cutting-edge sensors were designed for extreme environments. The potential applications for this absorber extend far beyond telecommunications, promising improvements in non-contact medical monitoring, advanced material inspection via tomographic imaging, and even in systems designed to detect hazardous substances. "This frequency range is expected to be used for various applications including wireless communications, noncontact vital monitoring systems, quality-inspection scanning systems via tomographic imaging, and security sensing for detecting hazardous materials," said Professor Shin-ichi Ohkoshi from the Graduate School of Science. Mass production of lambda-trititanium-pentoxide (λ-Ti3O5) is possible since λ-Ti3O5 can be synthesized on a large scale relatively easily and cost-effectively, and its surface coating can be obtained simply by mixing it with titanium dioxide nanoparticles. This breakthrough not only addresses one of the biggest hurdles in deploying 6G but also moves us closer to a future of ultra-fast, eco-friendly connectivity. By mitigating electromagnetic interference, the new absorber can ensure cleaner, more reliable signals for next-generation wireless networks. This development is a promising step toward realizing the vision of 6G, a network capable of supporting a truly connected, smart world.

The team including researchers at the University of Tokyo and Japanese chemical and iron-based alloy manufacturer Nippon Denko Co., Ltd., has developed the world's thinnest electromagnetic wave absorber, capable of absorbing waves in the 0.1–1 THz range. To date, only absorbers for waves below 0.3 THz have been made commercially available, but a frequency range beyond this is anticipated to be used for large-capacity 5G and 6G. "Our strategy was to combine an electrically conductive material with an insulating material. When a terahertz wave passes through, its alternating electric field induces scattering of the electric current generated inside of the conductive material, which causes energy loss and results in the dissipation of electromagnetic energy," explained Ohkoshi. "This dissipation of interfering waves enables the suppression of noise, i.e., unwanted waves, resulting in a clear signal." Composed of an electrically conductive metal oxide called lambda-trititanium-pentoxide (λ-Ti3O5), insulated within a titanium dioxide (TiO2) coating, the absorber is made entirely of titanium and oxygen. The absorber is made in powder form, which can be turned into an ultrathin film through compression molding and then applied to surfaces as needed. As we edge nearer to the anticipated rollout of 6G infrastructure around 2030, innovations like this are crucial. They highlight the incredible potential of materials science to overcome longstanding technical challenges, ensuring that our increasingly digital lives are powered by fast, reliable and sustainable technology. 

As the film is only 48 micrometers, or microns, thick (an average human hair is around 100 micrometers) and titanium is a highly abundant element, the absorber is economical for mass production and can be used even inside compact devices. It is also resistant to heat, water, light and organic solvents, and so can be used in outdoor environments and can even withstand harsh conditions. "The higher frequency range above 0.3 THz remains an unexplored area in materials science and I have been eager to contribute to its development," said Ohkoshi. "Our next step is to further develop the terahertz absorber and work toward its practical application, so that we can contribute to a more sustainable, eco-friendly, superfast wireless future."