• Thu. Mar 30th, 2023

Scientists create power-saving, tunable meta-devices for higher-precision, safe 6G communications — ScienceDaily


Mar 17, 2023

The future of wireless communications is set to take a giant leap with the advent of sixth-generation (6G) wireless technologies. A study group at City University of Hong Kong (CityU) invented a groundbreaking tunable terahertz (THz) meta-device that can handle the radiation path and coverage location of THz beams. By rotating its metasurface, the device can promptly direct the 6G signal only to a designated recipient, minimizing energy leakage and enhancing privacy. It is anticipated to supply a very adjustable, directional and safe signifies for future 6G communications systems.

The prospective of THz band technologies is limitless, as it has abundant spectrum sources to help one hundred Gbps (gigabit per second)- and even Tbps (terabit per second)-level ultrahigh-speed information price for wireless communications, which is hundreds to thousands of occasions more quickly than the 5G transmission information price. On the other hand, traditional THz systems use bulky, heavy dielectric lenses and reflectors, which can guide waves only to a fixed transmitter or detector, or transmit them to a single receiver positioned at a fixed position or covering a restricted location. This hinders the improvement of future 6G applications, which demand precise positioning and concentrated signal strength.

Current bulky systems hinder 6G applications

With the joint work of two study teams at CityU, led by Professor Tsai Din-Ping, Chair Professor in the Division of Electrical Engineering, and Professor Chan Chi-hou, Acting Provost and Director of the State Crucial Laboratory of Terahertz and Millimeter Waves (SKLTMW), a novel, tunable meta-devices that can completely handle the THz beam’s propagation path and coverage location was lately created to overcome these challenges.

“The advent of a tunable THz meta-device presents fascinating prospects for 6G communications systems,” mentioned Professor Tsai, who is an professional in the field of metasurfaces and photonics. “Our meta-device makes it possible for for signal delivery to precise customers or detectors and has the flexibility to adjust the propagating path, as necessary.”

“Our findings provide a variety of rewards for sophisticated THz communications systems, like safety, flexibility, higher directivity and signal concentration,” added Professor Chan, who specializes in terahertz technologies study.

Rotary metasurface with thousands of micro-antennas

The meta-device consists of two or 3 rotary metasurfaces (artificial, thin-sheet material with sub-wavelength thickness), which operate as effective projectors to steer the focal spot of THz beams on a two-dimensional plane or in a 3-dimensional space. With a diameter of 30 mm, every single metasurface has about 11,000 micro-antennas, which are just .25mm x .25mm in size and distinct from every single other. “The secret to the achievement of the meta-device lies in the meticulous calculation and design and style of every single micro-antenna,” mentioned Professor Tsai. By just rotating the metasurfaces without the need of extra space needs, the THz beam concentrate can be adjusted and directed to the specified X, Y and Z coordinates of the location accordingly.

With the very precise and sophisticated gear in the SKLTMW, the study group carried out experiments and verified that the two sorts of varifocal meta-devices they created — doublet and triplet meta-devices — can project the focusing spot of the THz wave into an arbitrary spot in a 2D plane and a 3D space, respectively, with higher precision.

This revolutionary design and style has demonstrated the capability of a meta-device to direct a 6G signal towards a precise place in two- and 3-dimensional space.

Because only the user or detector in a precise spot can get the signal, and the very concentrated signal can be flexibly switched to other customers or detectors without the need of wasting energy on nearby receivers or impairing privacy, the meta-device can improve directivity, safety and flexibility in future 6G communications with reduced power consumption.

Simple to scale up production at low price

The metasurfaces are fabricated with higher-temperature resin and a 3D printing technique created by the group. They are lightweight and little and can be effortlessly created in big scale at low price for sensible applications.

The novel THz tunable meta-device is anticipated to have fantastic application prospective for 6G communications systems, like wireless energy transfer, zoom imaging and remote sensing. The study group plans to design and style additional meta-device applications primarily based on THz varifocal imaging.

The findings had been published in the scientific journal Science Advances below the title “A 6G meta-device for 3D varifocal.”

Professor Tsai and Professor Chan are the co-corresponding authors. The co-very first authors are Mr Zhang Jingcheng, PhD student below Professor Tsai’s supervision, Dr Wu Gengbo, postdoctoral study fellow in the SKLTMW, and Dr Chen Mu-Ku, Assistant Professor in the Division of Electrical Engineering at CityU. Miss Liu Xiaoyuan, PhD student in the Division of Electrical Engineering, and Dr Chan Ka-fai, from the SKLTMW, also contributed to the study.

The study was supported by the University Grants Committee and the Analysis Grants Council of HKSAR, the Science, Technologies and Innovation Commission of Shenzhen Muncipality, the Division of Science and Technologies of Guangdong Province, and CityU.

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