Tailored and reconfigurable Huygens' metasurfaces

为了支持物联网（IoT）、5G蜂窝网络、卫星宽带互联网服务、联网自动驾驶汽车等新兴应用，下一代无线网络将严重依赖带宽充裕的毫米波频段（30ghz - 300ghz）。在这些频率下，能量成为一种宝贵的商品，而波的传播则由视线过程主导。因此，业界正在大力开发相控阵天线，这样，软件驱动的专用波束被引导给用户，以节省电力，实现先进的频谱管理并保持视线连接。尽管毫米波频率的集成电路技术取得了惊人的进步，但在成本和功耗方面，这种相控阵天线的部署仍然是一个主要挑战。因此，迫切需要对如何在传统相控阵之外随意操纵电磁波进行变革性的研究。在这个项目中，我们将使用惠更斯超表面的新范例来解决这一挑战：工程电磁表面可以以前所未有的方式控制电磁波。在这个项目中，我们将开发新的开创性研究方向，将这类技术提升到一个新的水平。例如，定制的超表面将被开发，使入射波可以以期望的偏转角度折射或反射，但具有完全定制的远场模式（例如控制副瓣电平和波束宽度）。这将在不需要像传统天线阵列那样的功耗馈电网络的情况下实现。这些表面可以从附近的小型天线阵列馈电，从而为新兴的5G移动和卫星网络提供一个整体强大的低成本和低调的天线平台。此外，一个全新的方向将被追求，这些超表面由合适的金属化制成，使其具有光学透明度。

The next generation of wireless networks will rely heavily on the millimetre-wave band (30GHz-300 GHz) where bandwidth is abundant in order to support emerging applications such as the Internet-of-things (IoT), 5G cellular , broadband internet service via satellites, and networked autonomous vehicles. At these frequencies, power becomes a precious commodity whereas wave propagation is dominated by line-of-sight processes. Hence industry is fiercely developing phased-array antennas such that, software-driven, dedicated beams are steered to users to save power, achieve advanced spectrum management and maintain line-of-sight connectivity. Despite spectacular advances in IC technologies at mm-wave frequencies, the deployment of such phased array antennas remains a major challenge in terms of cost and power dissipation. Therefore, there is a pressing need for transformative research on how to manipulate electromagnetic waves at will, beyond traditional phased arrays. In this project we will address this challenge using the new paradigm of the Huygens' metasurface: Engineered electromagnetic surfaces that can control electromagnetic waves in unprecedented ways. In this Project we will develop new pioneering research directions to bring this type of technology to the next level. For example, tailored metasurfaces will be developed such that incident waves can be refracted or reflected at a desired deflection angle but with completely tailored far-field patterns (e.g. controlled side-lobe levels and beamwidth). This will be achieved without the need of a power-consuming feeding network as in traditional antenna arrays. These surfaces could be fed from nearby small-scale antenna arrays thus providing an overall powerful antenna platform that is low cost and low profile for emerging 5G mobile and satellite networks. In addition, an entirely new direction will be pursued where these metasurfaces are made out of suitable metallizations to render them optically transparent.