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

在未经许可的57-66 GHz频谱中可用的巨大带宽可以支持几千兆位的传输。根据运行环境和应用的不同，范围在10m到100m之间的60 GHz无线网络很有吸引力，目前正在研发中。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，而且允许空中传输高清晰度(HD)未压缩视频流，可以支持无线高清视频互动游戏，允许在靠近城市的办公室之间建立安全的数千兆数据链路，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和快速的数据、音频和视频无线分发。仅限于这些应用，60 GHz芯片组的销量估计就达到数十亿个单位。在60 GHz频段，由于氧气和障碍物对电磁信号的吸收极高，外部干扰极低。不幸的是，高衰减与低发射机功率一起对传输质量产生不利影响。正如业界所指出的，这个问题可以通过在60 GHz收发机中实现定向天线来克服，能够自动控制其波束以实现最大信号接收。这项工作的目的是利用向列相液晶作为控制天线单元相位分布的手段，开发适用于60 GHz频段的波束可控平面天线阵，从而为多吉比特60 GHz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，并设计和制作集成最佳替代方案的波束定向天线阵。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，而目前还没有商业软件可用。在这项工作中，我们扩展了自己的先进的液晶和电磁建模方法，并将开发能够逐点处理完全不均匀和各向异性介质的软件工具，以便准确和可靠地分析和设计基于2D和3D的液晶器件，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.