VO2-based radiative thermal transistor with a semi-transparent base

International audienc

Digital Twins for Generic Radio Environments Parametrized by Reconfigurable Intelligent Surfaces: Physics-Based vs. Physics-Agnostic Surrogate Models

International audienceOptimizing the configuration of reconfigurable intelligent surfaces (RISs) in generic (potentially complex-scattering) radio environments for a desired communications or sensing functionality is challenging because of the non-linear manner in which the RIS impacts the wireless channel. The availability of a learned surrogate forward model of the mapping from RIS configuration to wireless channel can substantially facilitate the optimization problem. Here, we explore different approaches (physics-based vs. physics-agnostic) to learning such digital twins. © 2023, META Conference. All rights reserved

Digital Twins for Generic Radio Environments Parametrized by Reconfigurable Intelligent Surfaces: Physics-Based vs. Physics-Agnostic Surrogate Models

International audienceOptimizing the configuration of reconfigurable intelligent surfaces (RISs) in generic (potentially complex-scattering) radio environments for a desired communications or sensing functionality is challenging because of the non-linear manner in which the RIS impacts the wireless channel. The availability of a learned surrogate forward model of the mapping from RIS configuration to wireless channel can substantially facilitate the optimization problem. Here, we explore different approaches (physics-based vs. physics-agnostic) to learning such digital twins. © 2023, META Conference. All rights reserved

Efficient Computation of Physics-Compliant Channel Realizations for (Rich-Scattering) RIS-Parametrized Radio Environments

International audiencePhysics-compliant channel models for radio environments parametrized by reconfigurable intelligent surfaces (RISs) require the inversion of an "interaction matrix" to capture the mutual coupling between wireless entities (transmitters, receivers, RIS, environmental scattering objects) due to proximity and reverberation. The computational cost of this matrix inversion is typically dictated by the environmental scattering objects in non-trivial radio environments, and scales unfavorably with the latter's complexity. In addition, many problems of interest in wireless communications (RIS optimization, fast fading, object or user-equipment localization, etc.) require the computation of multiple channel realizations. To overcome the potentially prohibitive computational cost of using physics-compliant channel models, we i) introduce an isospectral reduction of the interaction matrix from the canonical basis to an equivalent reduced basis of primary wireless entities (antennas and RIS), and ii) leverage the fact that interaction matrices for different channel realizations only differ regarding RIS configurations and/or some wireless entities' locations

Experimentally realized physical-model-based frugal wave control in metasurface-programmable complex media

International audienceMetasurface-programmable radio environments are considered a key ingredient of next-generation wireless networks. Yet, identifying a metasurface configuration that yields a desired wireless functionality in an unknown complex environment was so far only achieved with closed-loop iterative feedback schemes. Here, we introduce open-loop wave control in metasurface-programmable complex media by estimating the parameters of a compact physics-based forward model. Our experiments demonstrate orders-of-magnitude advantages over deep-learning-based digital-twin benchmarks in terms of accuracy, compactness and required calibration examples. Strikingly, our parameter estimation also works without phase information and without providing measurements for all considered scattering coefficients. These unique generalization capabilities of our pure-physics model unlock unforeseen and previously inaccessible frugal wave control protocols that significantly alleviate the measurement complexity. For instance, we achieve coherent wave control (focusing or perfect absorption) and phase-shift-keying backscatter communications in metasurface-programmable complex media with intensity-only measurements. Our approach is also directly relevant to dynamic metasurface antennas, microwave-based signal processors and emerging in situ reconfigurable nanophotonic, optical and room-acoustical systems

Experimentally realized physical-model-based wave control in massively parametrized complex media

International audienc