Design of a Broadband Beam-Modulated Metasurface for Millimeter-Wave Applications

keywords:wide band, graphene, metasurface, millimeter-wave band, reflection phase, beam modulation

Abstract:Millimeter-wave applications are receiving considerable attention due to their high data transmission rates and large capacity. To meet the demands of modern communication systems for wide bandwidth, beamforming, and high radiation efficiency, a graphene-metal composite metasurface operating in the 88.5-94.6 GHz frequency range is proposed in this paper. The metasurface enables real-time beamforming control of its elements by adjusting the Fermi level of graphene. By optimizing the dimensions of the metal layer, the metasurface elements exhibit different phase and amplitude responses, as well as coding frequency ranges for various coding states. After optimized design, the encoded metasurface unit exhibits a reflection phase difference of 180 °± 20° in the broad frequency band of 88.5-94.6 GHz, at graphene Fermi levels of 0 eV and 1 eV, respectively, with all reflection amplitudes being greater than 0.7. Utilizing the unit design, the metasurface allows dynamic control of millimeter-wave beams, including beam steering and multi-beam switching, achieved by arranging the coding elements appropriately. Experimental results demonstrate that the maximum deflection angle of a single beam can be up to 105° (-55° to 50°) and the switching from 1 beam to 5 beams can be realized. The proposed metasurface presents a novel solution for multifunctional antenna design, holding potential applications in high-speed wireless local area networks, vehicular radar systems, satellite communications, and other fields. Its significance lies in advancing millimeter-wave communication technology.