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arXiv · 2101.02369

Re-configurable Intelligent Surface-based VLC Receivers Using Tunable Liquid-crystals: The Concept

Alain R. Ndjiongue·Telex M. N. Ngatched·Octavia A. Dobre·Harald Haas
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Abstract

Visible light communication (VLC) enables access to huge unlicensed bandwidth, a higher security level, and no radio frequency interference. With these advantages, VLC emerges as a complementary solution to radio frequency communications. VLC systems have primarily been designed for indoor scenarios with typical transmission distances between 2 and 5 m. Different designs would be required for larger distances. This paper proposes for the first time the use of a liquid crystal (LC)-based re-configurable intelligent surface (RIS) on improving the VLC signal detection and transmission range. An LC-based RIS presents multiple advantages, including the tunability of its photo-refractive parameters. Another advantage is its light amplification capabilities when under the influence of an externally applied field. In this paper, we analyze an LC-based RIS structure to amplify the detected light and improve the VLC signal detection and transmission range. Results show that mixing LC with 4 to 8 wt\% concentration of a dye such as the terthiophene (3T-2MB) improves the VLC transmission range of about 0.20 to 1.08 m. This improvement can reach 6.56 m if we combine 8 wt\% concentration of 3T-2MB and 0.1 wt\% concentration of trinitrofluorenone.

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Alain R. Ndjiongue, Telex M. N. Ngatched, Octavia A. Dobre, Harald Haas. 2021-01-07. Re-configurable Intelligent Surface-based VLC Receivers Using Tunable Liquid-crystals: The Concept. https://doi.org/10.1109/jlt.2021.3059599

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