Resonant metasurface with tunable asymmetric reflection
Resonant metasurface with tunable asymmetric reflection
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DOI：
10.1063/1.5046948
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发表时间：
2018-08-27
影响因子：
4
通讯作者：
Ginzburg, Pavel
中科院分区：
文献类型：
--
作者：
Filonov, Dmitry;Kozlov, Vitali;Ginzburg, Pavel
在一系列应用中，通过精心设计的结构来抑制后向散射电磁波是非常必要的，其中一些应用包括雷达隐身、天线隔离等。索尔兹伯里的屏幕由一面镜子组成，上面加了一层，传统上是用于这些目的。在这里，我们报告了一种互易屏的设计和实验演示，当从相反的方向照明时，它表现出不对称的反射特性。这种结构利用亚波长裂环谐振器和导线之间的近场磁电耦合，形成亚表面。虽然互易结构在传输中表现出完美的对称性，但通过仔细选择欧姆损耗，可以控制强后向散射不对称性，欧姆损耗是通过在谐振器中焊接集中电阻来实现的。根据负载的不同，元屏幕显示了在入射照明的正向和反向之间的完全对称和完全不对称反射之间变化的切换特性。当从一侧照明时，频率选择表面充当惠更斯元件，而当从另一侧照明时，频率选择表面则充当完美的镜子。通过控制欧姆损耗来定制电磁变形表面的非对称反射率的能力允许在天线罩和其他天线设备的设计中使用额外的自由度。此外，这一概念可以扩展到光学频率，其中阻性损耗可以通过直接向半导体器件中注入载流子来控制。由AIP出版公司出版。
Suppression of backscattered electromagnetic waves by carefully designed structures is highly demanded in a range of applications, some of which are radar invisibility, antenna isolation, and many others. Salisbury screens, composed of a mirror with an additional layer on top, are traditionally used for these purposes. Here, we report on the design and experimental demonstration of a reciprocal screen, which demonstrates asymmetric reflection properties when illuminated from opposite directions. The structure utilizes near-field magneto-electric coupling between subwave-length split ring resonators and wires, forming a metasurface. While the reciprocal structure demonstrates perfect symmetry in transmission, strong backscattered asymmetry is shown to be controllable by carefully choosing the Ohmic losses, which are implemented with lumped resistors soldered into the resonators. Depending on the load, the meta-screen demonstrates switching properties that vary between fully symmetric and completely asymmetric reflection between the forward and backward directions of incident illumination. The frequency selective surface acts as a Huygens element when illuminated from one side and as a perfect mirror when illuminated from the other. The ability to tailor the asymmetric reflectance of electromagnetic metasurfaces by controlling Ohmic losses allows employing additional degrees of freedom in designing of radomes and other antenna devices. Furthermore, the concept could be extended to optical frequencies, where resistive losses can be controlled via direct carrier injection into semiconductor devices. Published by AIP Publishing.