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This convergence between communication and sensing, known by the acronym ISAC (Integrated Sensing and Communication), is a notable advance since it currently requires two separate and energy‑hungry pieces of equipment. To switch from one mode to the other, today's materials and components with volatile electrical properties (such as vanadium dioxide or semiconductors) indeed require continuous power to maintain their state.
Conceptual illustration of the proposed multifunctional coding metasurface for near‑field sensing and far‑field communication in the terahertz (THz) range. Made from functional materials, the metasurface precisely manipulates reflected waves through optical activation.
This capability makes it possible to create a wide‑coverage communication environment via a dedicated high‑gain signal channel. Additionally, the metasurface improves passive object detection through wide‑angle scanning, which complements the frequency scanning range of the different coding patterns.
© 2025 The Author(s). Advanced Functional Materials published by Wiley‑VCH GmbH
Germanium telluride (GeTe) changes the game
This is where the work of Aurelian Crunteanu's team at the XLIM Institute (CNRS/University of Limoges) takes on its full importance.
In collaboration with the City University of Hong Kong, the scientists have developed a single‑layer metasurface that incorporates germanium telluride (GeTe). This phase‑change material allows switching from a conductive crystalline state to an insulating amorphous state solely under the effect of very short laser pulses. And unlike previous approaches, GeTe retains its state without continuous power supply. This property, called non‑volatility, drastically reduces power consumption.
The researchers validated and characterized the dual capabilities of their new device. In "sensing" mode, the metasurface exploits frequency dispersion in several configurations and thus covers a detection field of 40 degrees, with a high capability to locate small metallic objects.
In "communication" mode, the metasurface establishes a link at a rate of 5 gigabits per second. The signal‑to‑noise ratio is improved, and the error vector magnitude (EVM) (a signal quality indicator) is reduced compared to a reference metallic reflector.
There is no doubt that these performances position germanium telluride as a highly relevant solution for future 6G networks. With the same infrastructure capable of simultaneously transmitting data and mapping the environment, potential applications abound: low‑Earth‑orbit satellite networks, smart cities, advanced Internet of Things, connected vehicles, smart grids...
Wherever energy consumption and system compactness are critical, this new metasurface provides a sustainable and innovative solution.