The technology for 5G hasn’t even been widely deployed yet, but scientists are not waiting around for that. A research team from City University of Hong Kong (CityU) has developed a new-generation antenna that allows manipulation of the direction, frequency and amplitude of the radiated beam and is expected to play an important role in the integration of sensing and communications (ISAC) for 6th-generation (6G) wireless communications.
The team, led by Professor Chan Chi-hou, Acting Provost and Chair Professor of Electronic Engineering in the Department of Electrical Engineering at CityU, published their Sideband-Free Space-Time-Coding (STC) Metasurface Antennas paper in the nature electronics journal.
One of its innovative features of the new generation antenna is that there are many switches on its surface, and the response of the metasurface can be changed by turning these switches on and off to control the electric current, thus creating a desired radiation pattern and a highly-directed beam.
The radiated beam can scan and duplicate an image that is similar to a real person, so that mobile phone users can talk with each other with 3D hologram imaging.
Chan Chi-hou, Chair Professor of Electronic Engineering in the Department of Electrical Engineering at CityU

Structures and characteristics of traditional antenna cannot be changed once fabricated. However, a significant feature of the STC metasurface antenna is that the direction, frequency and amplitude of the radiated beam from the antenna can be changed through space-time coding software control, which enables great user flexibility.
The energy from the radiated beam of the new-generation antenna can be focused to a focal point with fixed or varying focal lengths, which can be used for real-time imaging and treated as a type of radar to scan the environment and feedback data, Professor Chan explained.
We hope that the new-generation antenna technology will become more mature in the future and that it can be applied to smaller integrated circuits at lower cost and in a wider range of applications.
Chan Chi-hou, Chair Professor of Electronic Engineering in the Department of Electrical Engineering at CityU
“The invention plays an important role in the ISAC for 6G wireless communications. For example, the radiated beam can scan and duplicate an image that is similar to a real person, so that mobile phone users can talk with each other with 3D hologram imaging. It also performs better against eavesdropping than the conventional transmitter architecture”, the professor exemplified.
The antenna was inspired by the new concept of AM leaky-wave antennas that Dr Wu Gengbo, now postdoctoral fellow at CityU and co-first author to the paper, proposed in 2020 in his PhD research. “A high-directivity beam is generated at the input frequency, allowing a wide range of radiation performance without having to redesign the antenna, except for using different STC inputs”, Dr Wu said.
“We hope that the new-generation antenna technology will become more mature in the future and that it can be applied to smaller integrated circuits at lower cost and in a wider range of applications”, Professor Chan concluded.