Sub-6-GHz Uplink Massive MIMO System Using Holographic Beamforming Metasurfaces: A Conceptual Development
Sub-6-GHz Uplink Massive MIMO System Using Holographic Beamforming Metasurfaces: A Conceptual Development
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DOI：
10.1109/lwc.2023.3237761
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发表时间：
2023-04
影响因子：
6.3
通讯作者：
Insang Yoo;David R. Smith
中科院分区：
文献类型：
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作者：
Insang Yoo;David R. Smith
我们提出了一个上行链路的大规模MIMO系统，使用全息元表面阵列作为扇区天线工作在3.5 GHz。该天线由一组矩形波导馈电超表面组成，这些超表面沿仰角方向沿着组合成平面孔径，每个超表面具有亚波长尺寸的超材料元件作为辐射器。超材料辐射器的设计使得波导馈电超表面实现引导（或参考）模式的全息解决方案，生成朝向指定方向的定向波束，从而形成多波束天线系统。我们证明了使用元表面的窄带上行链路大规模MIMO系统可以实现接近瑞利信道所提供的总容量。我们表明，支持多个波束的元表面可以在低于6 GHz的信道中在方位角方向上实现高空间分辨率，从而在基站和用户之间形成不相关的MIMO信道。此外，所提出的超表面天线在结构上简单、低成本且高效，并且因此适合于减轻配备有大型天线系统的大规模MIMO系统所共有的RF硬件问题。
We propose an uplink massive MIMO system using an array of holographic metasurfaces as a sector antenna operating at 3.5 GHz. The antenna consists of a set of rectangular waveguide-fed metasurfaces combined along the elevation direction into a planar aperture, each with subwavelength-sized metamaterial elements as radiators. The metamaterial radiators are designed such that the waveguide-fed metasurface implements a holographic solution for the guided (or reference) mode, generating a directional beam towards a prescribed direction, thereby forming a multibeam antenna system. We demonstrate that a narrowband uplink massive MIMO system using the metasurfaces can achieve the sum capacity close to that offered by the Rayleigh channel. We show that metasurfaces supporting multiple beams can achieve high spatial resolution in the azimuth directions in sub-6 GHz channels, and thereby form uncorrelated MIMO channels between the base station and users. Also, the proposed metasurface antenna is structurally simple, low-cost, and efficient, and thus is suitable to alleviate RF hardware issues common to massive MIMO systems equipped with a large antenna system.