Laboratoire de Traitement et Communication de l'Information (LTCI), Télécom Paris, Institut Polytechnique de Paris, 91120, Palaiseau, France.
Sci Rep. 2023 Jun 19;13(1):9871. doi: 10.1038/s41598-023-36828-4.
Metasurfaces are artificial materials that can provide properties not readily available in nature for the interaction with acoustic, elastodynamic, or electromagnetic waves. In Electromagnetics, metasurfaces allow particular functionalities to antennas, which in turn lately have been increasingly pushed to a multiband operation. To fully exploit metasurfaces' capabilities, the use of a metasurface reflector and a metasurface superstrate surrounding a radiating element in multiband antennas is interesting. However, such topology generally creates multiple reflections inside the formed cavity, known as Fabry-Pérot resonances. Here we show that one should tame this phenomenon to use two parallel metasurfaces surrounding a planar radiating element. We present the conditions to obtain directive, multiband antennas under such circumstances. The concepts are validated with a compact device for 5G/4G/Wi-Fi 2.4/5/6E performing a beam steering in the 5G without disturbing the radiation patterns of the other bands. This device demonstrates that the functionalities of two metasurfaces may be exploited in a single design if the presented conditions are respected. We also anticipate our work to be a starting point for other studies in the wave domain. For example, compact, multiband, beam-steerable microphones or sonar transducers with two parallel metasurfaces could be investigated in the future.
超表面是一种人工材料，可提供自然界中不易获得的特性，用于与声波、弹性动力学或电磁波相互作用。在电磁学中，超表面允许天线具有特定的功能，而天线最近又越来越多地被推向多频带操作。为了充分利用超表面的功能，在多频带天线中使用超表面反射器和超表面基底来包围辐射元件是很有趣的。然而，这种拓扑结构通常会在形成的腔体内产生多次反射，称为法布里-珀罗共振。在这里，我们展示了应该控制这种现象，以使用两个平行的超表面来包围平面辐射元件。我们提出了在这种情况下获得定向、多频带天线的条件。该概念通过一个用于 5G/4G/Wi-Fi 2.4/5/6E 的紧凑设备得到了验证，该设备在不干扰其他频段辐射模式的情况下，在 5G 频段进行了波束转向。该设备表明，如果满足所提出的条件，两个超表面的功能可以在单个设计中得到利用。我们还期望我们的工作成为波域中其他研究的起点。例如，未来可以研究具有两个平行超表面的紧凑型、多频带、波束可转向的麦克风或声纳换能器。
