Metasurfaces can manipulate electromagnetic energy far beyond the limits of natural materials. An EU-funded project has developed a multifunctional and more accessible version that could enable easily programmable, smarter environments.

State-of-the-art, flat structures called metasurfaces can filter and steer light and sound, render an object completely invisible to electromagnetic waves, and much more. They can deliver automation, remote operation and advanced performance to a wide variety of existing systems, with applications in communications, medical imaging, sensing and security.

However, individual metasurfaces are currently restricted to a specialized function, cannot be reused, and can only be designed by specialised engineers – all of which limits their impact and accessibility.

The EU-funded VISORSURF project has brought together physicists, material scientists, electrical engineers and computer scientists with the aim of producing a programmable ‘plug-and-play’ metasurface.

The project’s resulting hardware platform – known as the HyperSurface – provides the many electromagnetic functions of metasurfaces in a single structure, which can be controlled and reconfigured by software.

This revolutionary approach paves the way for new opportunities in wireless communications and programmable wireless environments. The VISORSURF team envisages that the use of HyperSurfaces to link networks with objects and physical environments will create smarter systems that are far more responsive to user demands. Walls that absorb radiation or block digital eavesdropping, and wireless, long-distance charging of devices are among the many possibilities.

‘VISORSURF’s work can enable smart environments of any scale – from indoors wireless communications to medical imaging equipment,’ says project coordinator Costas Soukoulis of the Foundation for Research and Technology – Hellas, in Greece. ‘HyperSurfaces have succeeded in bringing metasurface capabilities to the Internet of Things world.’

Metasurfaces in the mainstream

VISORSURF researchers started out by modelling the different ways in which metasurfaces control electromagnetic waves. They then studied the interplay between these functionalities to find ways of combining them into a single metasurface. The team designed a measurement and evaluation test bed to carry out this experimental research.

Embedded in the HyperSurface is a network of miniaturised antennas and controllers on a fabric array, which receive commands from a software program via Wi-Fi, a mobile phone or a computer. The controllers operate an array of switches to make alterations to the HyperSurface, delivering the required changes in electromagnetic behaviour.

The team is also exploring the use of a graphene-based control medium – a nanomaterial just a single carbon atom thick – to provide even finer control.

A central aim of the VISORSURF project has been to open up the vast potential of metasurfaces to mainstream use by making the technology accessible to non-specialists.

To achieve this, the team is translating the advanced physics concepts underlying metasurfaces into software. This means any developer could use the HyperSurface to integrate the capabilities of metasurfaces into novel applications, without prior knowledge of the physics involved.

Booming market

‘We believe that integrating HyperSurfaces into communications, medical imaging, sensing, security and other fields will provide advanced solutions enabling automation, remote operation, advanced performance and more,’ says Soukoulis. ‘And we’re seeing a rapid evolution in areas where this could be applied.’

For example, in the medical imaging, multimedia and acoustics market – with an expected global revenue of USD 20.9 billion in 2019 – HyperSurfaces can act as environment-adapting absorbers of electromagnetic energy. This empowers them to operate as noise-cancelling or electromagnetic-shielding devices.

The team also sees great potential for HyperSurfaces in the wireless communications and radar market.

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