Controlling microwave radiation from sources by design of their environment

该项目将研究使用超材料和超表面来优化天线性能，如效率和指向性。改进天线设计的其他驱动因素包括需要最小化重量、厚度和横截面积，以延长带宽并降低成本。该项目将专注于设计新颖的元表面，赋予人工边界条件，以实现上述目标。超表面将被概念化、设计、建模、制造和实验测试，最初不参考天线。将考虑提供宽带频率响应的多层和多域设计-这可能需要这些表面内谐振元件的小型化，这可以通过考虑复杂的几何形状或使用高折射率材料来实现。该项目的第二阶段将看到metassurfaces与最简单的散热器/天线设计相结合，以便了解两者之间的耦合。然后，研究人员将开发超表面设计，以匹配辐射元件中的电流分布，或者以其他方式操纵天线的性能和功能：这可能包括考虑各向异性表面。一旦了解了这一点，我们就会考虑更复杂的“现成”和定制的辐射元件设计，以便最大限度地发挥表面辐射天线系统的优势。莱昂纳多感兴趣的天线是非常宽带的，覆盖几十千兆赫，它们在民用和国防应用中得到了应用，比如无线通信和航空。这个学生项目的新颖之处在于应用超材料来优化天线性能。很有可能在学习期间研究或开发活性或可重构的超材料。偏振操纵（最大限度地有效利用天线孔径）也是我们感兴趣的，也在项目范围内。在国防应用中，雷达截面（RCS）也很重要，因此也将被考虑用于有利的天线和超材料选择。

This project will investigate the use of metamaterials and metasurfaces for optimising antenna performance, such as efficiency and directivity. Other drivers in improving antenna design include the need to minimise weight, thickness and cross-sectional area, to extend bandwidth and reduce cost.The project will focus on the design of novel metasurfaces that impart artificial boundary condtions in order to achieve the ambitions above. Metasurfaces will be conceptualised, designed, modelled, fabricated and experimentally tested initially without reference to an antenna. Multilayered and multidomained designs will be considered that provide a broadband frequency response - this will likely requrie the minaturisation of the resonant elements within these surfaces, and this can be obtained by considering complex geomtries or the use of high-index materials. The second stage of the project will see the metasurfaces combined with the simplest radiator / antenna designs in order to understand the coupling between the two. The researcher will then develop the metasurfaces designs in order to match the current distribution in the radiating element, or to otherwise manipulate the antenna performance and functionality: this might include the consideration of anisotropic surfaces. Once this is undertsood, we will then consider more complex 'off-the-shelf' and bespoke designs of the radiating element in order to maximise the benefits of the combined surface-radiator antnnna system.The antennas of interest to Leonardo are very broadband covering tens of GHz similar - they find application in civil and defence applications such as wireless communication and aviation. The novelty of this studentship is in the application of metamaterials to optimise the antenna performance. It is quite possible that active or reconfigurable metamaterials are investigated or developed in the course of the studentship. Polarisation manipulation (to maximise the efficient use of the antenna aperture) is also of interest and within the scope of the project. In defence applications, radar cross-section (RCS) can also be important and so will also be considered for favoured antenna and metamaterial options.