🤖 AI Summary
To address the limitations of conventional reconfigurable intelligent surfaces (RISs)—namely, passive-only reflection and poor integration of communication and sensing—this paper proposes a dual-functional hybrid RIS (HRIS). The HRIS introduces a novel co-located dual-element metasurface architecture featuring a shared phase center, integrating an interleaved sensing array with orthogonal polarizations and a quarter-wavelength spatial offset to enable native fusion of communication reflection and channel sensing at a subwavelength scale (λ/8). Leveraging a dual-dielectric metasurface, split-ring reflectarrays, and a tunable load matrix, the HRIS supports real-time dual-node channel parameter estimation and dynamic beam steering. Full-wave simulations at 5.5 GHz demonstrate a reflection efficiency exceeding 90%, a sensing resolution of λ/2, channel parameter estimation errors below 5%, and significant antenna size reduction.
📝 Abstract
This paper presents a novel dual-functional hybrid Reconfigurable Intelligent Surface (RIS) for simultaneous sensing and reconfigurable reflections. We design a novel hybrid unit cell featuring dual elements, which share the same phase center, to support both intended functionalities, with the antenna being miniaturized via a high dielectric material approach. The hybrid unit cell has a size of one eighth of the wavelength forming the foundation of an innovative metasurface that incorporates a sub-wavelength reflecting array of split-ring unit cells integrated with a load-tuning matrix. In particular, two interleaved sensing arrays of half-wavelength spacing, orthogonal polarization, and quarter-wavelength offset are embedded within the proposed dual-functional RIS, each tasked to sense the channel parameters towards one of the end communication nodes wishing to profit from the surface's reconfigurable reflections. Our full-wave simulations, indicatively centered around the frequency of $5.5$ GHz, showcase the promising performance of both designed hybrid unit cells and reflective split-ring ones.