Skip to main content

VisorSurf - A Hardware Platform for Software-driven Functional Metasurfaces

Periodic Reporting for period 3 - VISORSURF (VisorSurf - A Hardware Platform for Software-driven Functional Metasurfaces)

Reporting period: 2019-07-01 to 2020-12-31

What if the laws of electromagnetism could be customized, rather than being simply adhered to? The VISORSURF project studies this direction, exhibiting a paradigm shifting potential for a wide range of applications. The project is producing a first-of-its kind material, the HyperSurface, which can sense electromagnetic waves impinging upon it and manipulate them in ways dictated by software.

A core concept of VISORSURF are the metasurfaces, a concept from Physics, which has recently enabled the realization of novel objects with engineered and even "unnatural" electromagnetic functionalities. VISORSURF introduces a new kind of networked metasurfaces that can host metasurface functionalities described in software, such as parametric wave steering, absorbing, filtering and polarizing. The HyperSurface is a merge of properly-designed metasurfaces and novel electronic nano-controllers, resulting in a reconfigurable metasurface, whose properties can be changed via a software interface. The controllers receive programmatic directives and perform simple alterations in the metasurface aspect of HyperSurfaces, adjusting their overall electromagnetic behavior and attaining the required high-level functionality.

From another innovative aspect, the project enables the translation of advanced concepts of Physics in software, which nowadays constitutes the “common language” for all scientific fields, promoting open-access to knowledge. Thus an additional ambition is to bring the physics behind metasurfaces into the realm of software developers, eventually treating the electromagnetic behavior of objects as an app, as shown in the attached Figure.
For reporting period 1 the project achieved its goals, which are summarized as follows:
1) Establish a cross-discipline understanding among the consortium partners.
2) Establish a design/implement/manufacture/evaluate workflow between the academic and industrial partners.
3) Derive an initial design of the HyperSurface hardware.
4) Derive an initial design of the HyperSurface software.
5) Initiate the theoretic studies of the HyperSurface capabilities, decoupled from manufacturing restrictions.
6) Initiate the dissemination efforts, acquainting the academic world and the broader public with the novel HyperSurface concept.

For reporting period 2, the project achieved the following goals:
1) To refine the HyperSurface prototype design process, yielding a wide tenability range in absorption and wave steering.
2) Schedule some key intermediate prototypes, to gain valuable experience on critical aspects of the official project prototypes.
3) To manufacture a development-level prototype early on, and use it to complete the measurements testbed and test the developed software (Electromagnetic (EM) Application Programming Interface (API) and Compiler).
4) To implement a complete version of the EM Compiler, which combines concepts of electromagnetism with computer science principles for transparent usage and interfacing with smart, connected systems.
5) To define the experimental setup specifications of the project's final demonstrator, which a tunable EM wave absorber which exhibits perfect absorption for any incidence angle.
6) To showcase the Programmable Wireless Environment concept as a promising application of connected HyperSurfaces.
7) To study the scaling trends of HyperSurfaces in the pathway to determining the performance and cost of future deployments.

For reporting period 3, the project proceeded to the manufacturing and testing of the prototypes (perfect absorbers) aimed at 5GHz and the THz band. The main goals which were achieved are the following:
1) Manufacturing of the 5 GHz prototype which uses chips as tunability elements; all the HyperSurface components were tested successfully. (Final testing delayed due to Covid-19 pandemic).
2) Manufacturing tunable graphene-based metasurfaces suitable for realization of perfect all-angle absorber and beam steering device at THz; the desired response of the non-reconfigurable variant of the prototype was verified.
Additional achievements of the period include:
1) Theoretical exploration of additional functionalities appropriate for implementation via our HyperSurfaces, including polarization conversion, beam steering, multi-band absorption and asymmetric reflection.
2) Final refinement and optimization of the software related with computer-control of the HyperSurface response.
3) Development of a scalability model for the intra-HyperSurface network of HyperSurfaces (HSF) accounting for the motion, HSF size, network bandwidth and topology.

The project dissemination outcome in its 4 years includes more than 60 journal publications, more than 20 invited talks at conferences, organizations of 1 summer school and 3 special sessions in conferences, one patent, and publication of a book ("The Internet of Materials" (1st ed.), CRC Press, 2021. ISBN 9780367457389.)
Classic metasurfaces are functional media which have promising applications, yet they cannot react to environmental changes and
adapt themselves in a controllable manner. As an upshot, they cannot allow for point-to-point or programmatic control, i.e. no interface,
means for automation and formal programming. Even at the level of plain, static metasurfaces, many significant configurations are
hindered by the lack of metasurface tuning competences and their limited working bandwidth, primarily attributed to the resonance
nature of their sub-wavelength building blocks. Presently, research acknowledges the need to attain tunable, switchable, nonlinear
and sensing functionalities at the metasurface level. However, there is no proposal for software-defined smart control or equivalent.

VISORSURF addresses the shortcomings of the literature and proposes true, software definition of the EM properties of a medium, allowing its interconnection to smart control loops in real-time.
VISORSURF is expected to allow software developers and engineers to design systems that contain the electromagnetic behavior of objects into their control loops, without required knowledge
of the underlying Physics. This evolution comes as a timely extension of the Internet-of-Things (IoT) concept. IoT constitutes a robust, complete hardware platform (hardware and full
software stack included) for connecting anything-to-anything, under a considerable range of conditions and use-cases: houses that perform
access control, unlocking/locking doors when the owner approaches, and regulating the room temperature, lights and music according to
his perceived mood; medical implants can calls the doctors if they shows signs of failure, long before the user notices, and more. Novel
IoT products are being released almost daily, at a trend that is expected to yield 20-30 billion connected IoT devices by 2020.
Software-defined metasurfaces can give the already successful IoT concept a new application field over the electromagnetic behavior
of objects. Coupled with related efforts seeking to provide control over mechanical properties, IoT can extend to IoM (Internet-of-Materials),
offering unprecedented capabilities.
The electromagnetic behavior of the HyperSurface can change through an app.