City University of Hong Kong (CityU) recently developed a revolutionary meta-device capable of controlling the radiation direction and area of tunable terahertz (THz) beams. Rotating its metasurface allows the device to quickly direct 6G signal directly towards an assigned receiver, minimizing power leakage while improving privacy. It is expected to become an adjustable, directional, and highly secure device for future 6G communications.
THz-band technology holds immense promise, as it boasts ample spectrum resources to support 100 Gbps and even Tbps (terabits/second) ultrahigh speeds for wireless communications - hundreds to thousands faster than 5G's data rate.
Unfortunately, traditional THz systems rely on heavy dielectric lenses, reflectors, and bulky reflectors, which cannot guide waves towards a fixed detector or transmitter or send them anywhere but one receiver in an isolated spot or small area; this prevents future 6G applications from being developed as they require precise positioning, concentrated signal strength, and limited coverage areas.
Two research teams from CityU, led by Professor Tsai din-Ping (Chair Professor in Electrical Engineering) and Professor Chan Chihou (Acting Provost and Director of State Key Laboratory of Terahertz and Millimeter Waves SKLTMW), have created a novel tunable device that allows full control over the propagation direction and coverage of THz beams.
"The advent of a tunable THz meta-device presents exciting prospects for 6G communications systems," said Professor Tsai. "Our meta-device allows for signal delivery to specific users or detectors and has the flexibility to adjust the propagating direction, as needed."
Rotary metasurface with thousands of micro-antennas
The Meta-device consists of two to three rotating, thin-sheet metasurfaces (artificial and thin-sheet material of sub-wavelength thickness) that act as projectors for THz beams in a 2-D plane or 3-D space. Professor Tsai explained that the success of his device lies in precisely designing each micro antenna, and rotating them without extra space is all it takes to adjust focus and direct the beam towards its specified destination coordinates.
A research team conducted experiments to verify that both types of Varifocal Metadevices - doublet and triplet - project the THz wave's focal point into an arbitrary location within both 2D space and 3D area. This innovative design has demonstrated how a metadevice can direct 6G signals to precise locations in two and three-dimensional space.
Easy to scale up production at low cost
The team developed 3D printing technology and high-temperature glue to fabricate metasurfaces. They are lightweight and portable, meaning they can be produced in large numbers at low costs for practical uses.
The 6G telecom system's THz-tunable meta-device has the potential to support a range of applications, such as remote sensing, wireless power transfers, zoom imaging, and wireless power sources. The research team plans on creating additional meta-devices based on THz varifocal photography in the near future.
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Sead is a seasoned freelance journalist based in Sarajevo, Bosnia and Herzegovina. He writes about IT (cloud, IoT, 5G, VPN) and cybersecurity (ransomware, data breaches, laws and regulations). In his career, spanning more than a decade, he’s written for numerous media outlets, including Al Jazeera Balkans. He’s also held several modules on content writing for Represent Communications.