Due to the growing scarcity of spectrum resources in the low-frequency band, the requirement of beam-reconfigurable antennas in the millimeter wave band is urgent. In this paper, a W-band graphene-based metasurface working in a broad bandwidth is proposed with reflective amplitude coding. Here, graphene sheets play a dual role in radiating and regulating electromagnetic waves. By adjusting the Fermi levels of graphene, the reflective amplitude and phase of the metasurface can be modulated simultaneously, enabling multi-beam switching and beam deflection in far-field. The proposed metasurface achieves amplitude-phase modulation within a significantly wide bandwidth which covers 75-91.5 GHz and 99.3-115 GHz. By optimizing the coding patterns, the proposed graphene-based metasurfaces are able to not only realize 2-D beam steering, but also achieve beam switching from single beam to four beams at 87 GHz. The proposed design provides a novel solution for the flexible manipulation of millimeter waves, which can be applied to various fields such as vehicle radar, satellite communication, 6G wireless communication, and beyond.
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http://dx.doi.org/10.3390/ma16134633 | DOI Listing |
Phys Chem Chem Phys
January 2025
College of Mechanics and Engineering Science, Hohai University, Nanjing, 211100, China.
Driven by the pressing demand for integration and miniaturization within the terahertz (THz) spectrum, this research introduces an innovative approach to construct chiral structures using dichroism as the target function. This initiative aims to tackle the prevalent issues of single-functionality, narrow application scope, and intricate design in conventional metasurfaces. The proposed multifunctional tunable metasurface employs a graphene-metal hybrid structure to address the critical constraints found in existing designs.
View Article and Find Full Text PDFLight Sci Appl
January 2025
Department of Physics, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
Graphene has unique properties paving the way for groundbreaking future applications. Its large optical nonlinearity and ease of integration in devices notably makes it an ideal candidate to become a key component for all-optical switching and frequency conversion applications. In the terahertz (THz) region, various approaches have been independently demonstrated to optimize the nonlinear effects in graphene, addressing a critical limitation arising from the atomically thin interaction length.
View Article and Find Full Text PDFThe bulk photovoltaic effect (BPVE) and its artificial variant generate photocurrent under zero external bias in non-centrosymmetric systems, particularly in on-chip miniaturized metasurface-based photodetectors. Despite significant advancements, enhancing the efficiency of local photocurrent collection remains a challenge, often impeded by non-uniform flow fields in graphene caused by nanoantenna contacts, which lead to carrier transport losses. In this study, we conducted a comprehensive investigation into the regulation of local photocurrent collection in zero-bias optoelectronic metasurface-based photodetectors and explored the impact of nanoantenna array configurations on photocurrent efficiency.
View Article and Find Full Text PDFNanophotonics
August 2024
School of Opto-Electronic Engineering, Zaozhuang University, Zaozhuang 277160, China.
Broadband and omnidirectional absorption of electromagnetic waves is required in various technologies, such as stealth, high quality wireless communications, spacecraft shielding. In this study, we theoretically and numerically study a graphene-based absorber achieving broadband and omnidirectional absorption from 4 GHz to 100 GHz and 0 to 50 ∼70 , with over 90% absorption efficiency. By applying a thin layer of graphene upon a SiO moth-eye structure, we show that electromagnetic waves can be effectively absorbed in the graphene layer and that the structure is optically transparent, ideal for civilian and military applications.
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