Next Generation metasurfaces: tensorial surfaces for novel antenna functionality

下一代超表面：用于新颖天线功能的张量表面

• 批准号: 2638760
• 金额: --
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2638760
• 关键词: Next; Generation; metasurfaces; tensorial; surfaces

It is the focus of this project to design, model, fabricate and characterise 2D metasurfaces, or the surface 3D metamaterials or composites, that demonstrate a tensorial surface impedance. When combined with appropriate antenna designs, the findings will support future civil applications like the internet of things, high frequency imaging systems for screening, scanners and tomography systems for medical diagnostics and wireless measurement and smart meter systems.Propagation of energy along scalar impedance surfaces for the purpose of guiding and radiating electromagnetic waves has been studied for some time. Both 1-D and 2-D artificial impedance surfaces have been explored to control guided waves and leaky-wave radiation. Indeed the 'Sievenpiper-mushroom' array [1] is perhaps the best known metasurface, and Exeter researchers have successfully used an inhomogeneous design based on this to fabricate and experimentally test a surface-wave Luneburg lens device [2]. Similar structured surfaces can also be employed to reduce the height of antenna systems. This is because, at their resonant frequency, the surface forbids the propagation of surface waves, and presents a magnetic-conductor boundary condition. Unlike perfect electric conductors, materials with this magnetic boundary condition do not exist in nature: it forces the tangential components of magnetic fluxes and the normal components of electric fields to be zero. In this way radiating elements can be placed very close to the surface without the detrimental effects associated with the interference created by images sources induced by a simple metal ground plane.This project takes our understanding beyond the current state-of-the art [3-6], and is centred around an exploration of coupling antenna eignenmodes to inhomogeneous and tensorial impedance surfaces. These metasurfaces can be those of the printed-circuit-board-type, or the surface of 'bulk' metamaterials or magnetic composites. Initially we will work to understand the extent of the parameter space (in terms of the boundary conditions) that can be explored. The next step is then to place a simple dipole source close to these surfaces to understand how they can influence the source's radiation characteristics. In turn, we will consider how the efficiency, functionality or directivity of more complex antenna can be improved, as well as reduction of size or thickness, and the polarisation of the radiated beam. A resulting structure that is lightweight, potentially conformal, and with compact volume, is particularly valuable to aerospace and space applications.The challenges are numerous and difficult, but we expect great advances in fundamental understanding and device design from a competent researcher. There are a wealth of studies in the scientific literature, and the researcher will be required to undertake a substantial review to provide the sponsors with a summary of the state-of-the-art on metasurfaces, and composite materials. He or she will need to become familiar with the physics of anisotropic, layered and magnetic materials, and the fundamentals and complexities of wave optics. The project will include analytical, modelling, fabrication and experimental elements, and the student will be expected to interact closely with other researchers working in related areas.

该项目的重点是设计、建模、制造和模拟2D超材料表面，或表面3D超材料或复合材料，以展示张量表面阻抗。当与适当的天线设计相结合时，这些发现将支持未来的民用应用，如物联网，用于筛查的高频成像系统，用于医疗诊断的扫描仪和断层扫描系统以及无线测量和智能电表系统。能量沿沿着标量阻抗表面传播以引导和辐射电磁波的研究已经有一段时间了。已经探索了1-D和2-D人工阻抗表面来控制导波和漏波辐射。事实上，“Sievenpiper-mushroom”阵列[1]可能是最著名的超表面，埃克塞特的研究人员已经成功地使用基于此的非均匀设计来制造和实验测试表面波Luneburg透镜设备[2]。也可以采用类似的结构化表面来降低天线系统的高度。这是因为，在它们的谐振频率下，表面禁止表面波的传播，并呈现出磁导体边界条件。与完美电导体不同，具有这种磁边界条件的材料在自然界中并不存在：它迫使磁通量的切向分量和电场的法向分量为零。通过这种方式，辐射元件可以放置在非常靠近表面的位置，而不会产生与简单金属接地层引起的图像源产生的干扰相关的有害影响。该项目使我们的理解超越了当前的最新技术水平[3-6]，并围绕着将天线本征模耦合到非均匀和张量阻抗表面的探索。这些超材料表面可以是印刷电路板类型的超材料表面，也可以是“块状”超材料或磁性复合材料的表面。首先，我们将努力了解可以探索的参数空间的范围（就边界条件而言）。下一步是将一个简单的偶极子源靠近这些表面，以了解它们如何影响源的辐射特性。反过来，我们将考虑如何提高更复杂天线的效率，功能或方向性，以及减小尺寸或厚度，以及辐射波束的极化。由此产生的结构，重量轻，潜在的共形，并与紧凑的体积，是特别有价值的航空航天和空间应用。挑战是众多的和困难的，但我们期待着从一个称职的研究人员在基本的理解和设备设计的巨大进步。科学文献中有大量的研究，研究人员将被要求进行实质性审查，以向申办者提供超颖表面和复合材料的最新技术水平总结。他或她将需要熟悉各向异性，分层和磁性材料的物理学，以及波动光学的基本原理和复杂性。该项目将包括分析，建模，制造和实验元素，学生将有望与相关领域的其他研究人员密切互动。