Liquid-Crystal-Based Beam Steerable Planar Antennas for 60 GHz Wireless Networks

57-66 GHz频谱的巨大带宽可以支持多千兆传输。根据操作环境和应用，距离在10米到100米之间的60 GHz无线网络具有吸引力，目前正在研究和开发中。它们可以在消费和专业电子市场上有巨大的应用。无线网络不仅消除了通信终端之间的布线，而且还允许通过空中传输高清（HD）未压缩视频流，可以支持无线高清视频互动游戏，允许在距离较近的城市办公室之间建立安全的千兆数据链路，并可以在飞机、火车、汽车、办公室、医院和许多其他有趣的地方提供安全快速的数据、音频和视频无线分发。仅就这些应用而言，60 GHz芯片组的销售估计将达到数十亿台。在60 GHz频段，由于氧气和障碍物对电磁信号的吸收非常高，外部干扰非常低。不幸的是，高衰减和低发射机功率会对传输质量产生不利影响。正如业界所指出的那样，这个问题可以通过在60 GHz收发器中实施定向天线来克服，定向天线能够自动控制其波束以获得最大的信号接收。这项工作的目的是开发60千兆赫波段的波束可操纵平面天线阵列，使用向列液晶作为控制天线元件相位分布的手段，从而为多千兆60千兆赫无线网络提供紧凑，低功耗和低成本的原型天线。为此，我们将研究、开发和比较两种基于液晶的移相器，并设计和构建集成最佳替代方案的波束转向天线阵列。移相器性能的优化和天线阵列的开发都需要详细的液晶和电磁建模，而这些都没有商业软件可用。在这项工作中，我们扩展了自己先进的液晶和电磁建模方法，并开发了能够处理完全不均匀和各向异性介电体（逐点）的软件工具，以便准确可靠地分析和设计二维和三维液晶器件，包括移相器和天线。

The huge bandwidth available in the unlicensed 57-66 GHz spectrum can support multi-gigabit transmission. Depending on the operating environment and application, 60 GHz wireless networks with ranges between 10 m to 100 m are attractive and currently are under research and development. They can have immense applications in consumer and professional electronic markets. Not only do wireless networks eliminate cabling between communicating terminals, but they permit high definition (HD) uncompressed video streaming over air, can support wireless HD video interactive games, allow secure multi-gigabit data link between close city offices, and can provide safe and fast data, audio and video wireless distribution in planes, trains, cars, offices, hospitals and many other places of interests. Restricted to these applications alone, the sale of 60 GHz chipsets is estimated to run into billion of units. In the 60 GHz band the external interference is extremely low as the absorption of electromagnetic signals by oxygen and obstacles are extremely high. Unfortunately, the high attenuation together with the low transmitter power adversely affects the transmission quality. As flagged by the industry, this problem can be overcome by the implementation of directional antennas in 60 GHz transceivers, capable of steering their beams automatically for maximum signal reception. The aim of this work is to develop beam steerable planar antenna arrays for the 60 GHz band using nematic liquid crystals as a means for controlling the phase distribution over the antenna elements and hence, to provide prototype antennas which are compact, low-power and low-cost for multi-gigabit 60 GHz wireless networks. For this purpose, we will investigate, develop and compare two types of phase shifters based on liquid crystals, and design and build beam steering antenna arrays integrating the best alternative. Both the optimisation of the phase shifter performance and the development of the antenna arrays require detailed liquid crystal and electromagnetic modelling for which there is no commercial software available. In this work, our own advanced liquid crystal and electromagnetic modelling methods are extended and software tools capable of dealing with fully inhomogeneous and anisotropic dielectrics (on a point by point basis) will be developed in order to analyse and design accurately and reliably the 2D and 3D liquid-crystal-based devices including phase shifters and antennas.