Antenna Analysis, Design and Measurement Techniques

加拿大无线行业继续在系统和设备层面进行创新。无线通信无处不在，如果有什么东西是无线的（而不是有线的），就需要天线。我提出的研究目标是利用电磁原理开发工具，用于分析、设计和测量许多新兴无线应用的改进天线。贯穿提案的主题是让电磁直接指导我们实现所需性能的天线元件形状。由于无线网络中存在传播问题，除了在基站上的天线外，无线天线必须具有宽辐射模式（低指向性）。它们必须适应便携式设备的拥挤环境，因此很难设计。这种困难增加了未来系统中使用的认知无线电和多输入/多输出能力，以克服频谱稀缺性，因为这些天线将需要多频段，在单个移动设备上有几个紧密间隔的天线。需要新的结构和设计方法。我们之前已经开发了一种独特的形状合成技术，可用于设计单波段的下一代天线，它使用便携式无线设备中的“剩余空间”作为起始形状。研究计划的一部分目标是将该方法扩展到多频段天线，以及两个或多个非常紧密间隔的天线的配置。*******由于带宽需求，第五代无线系统将使用使用毫米波频段（用于蜂窝移动服务的28 GHz至90 GHz）的更小的小区，利用这些频率的高传播损耗来防止小区相互干扰。将需要高指向性天线，其中一些需要可切换波束。为了满足严格的成本限制，天线必须使用印刷技术。在毫米波频率下，传统印刷阵列的波束形成网络中的损耗是一个限制因素。发射阵列和平面全息天线采用印刷技术，但不需要波束形成网络。我将通过使用形状碎片元件方法（我们已经成功地在反射阵列工作中使用）来推进我对发射阵列的研究，以设计多焦点发射阵列（启用开关波束）和多波段发射阵列（在广泛分离的多个频率上工作）。平面全息天线可以做得非常低调（在商业应用中很重要），将馈电集成到支持全息图的基板上，但受到低孔径效率的影响。我们将使用我们开发的扩展电磁建模能力来合成馈电安排，以提高孔径效率

The Canadian wireless industry continues to be innovative at both the system and equipment level. Wireless communications pervades everything, and if anything is wireless (as opposed to wired) antennas are required. The objective of my proposed research is the use of electromagnetic principles for developing tools for the analysis, design and measurement of improved antennas for the many emerging wireless applications. A theme running through the proposal is that of letting the electromagnetics directly guide us as to the antenna element shapes needed to achieve the performance we desire.***Except for those on base-stations, wireless antennas must have broad radiation patterns (low directivity) because of the propagation issues extant in wireless networks. They must fit in the crammed environment of portable devices and so can be difficult to design. This difficulty is increased for the cognitive radio and multiple-input/multiple-output capabilities to be used in future systems to overcome spectrum scarcity, since these antennas will need to be multiband, with several closely-spaced antennas on a single mobile device. New configurations and design methods are needed. We have previously developed a unique class of shape synthesis technique that can be used for the design of single-band varieties of such next-generation antennas, which uses as a starting shape the "leftover space" in a portable wireless device. The goal of one part of the research proposal is to extend the approach to multiband antennas, and configurations of two or more very closely-spaced antennas.*******Fifth-generation wireless systems will use smaller cells that utilize millimetrewave bands (28 GHz to 90 GHz for cellular mobile services) due to bandwidth demand, with the high propagation losses at these frequencies exploited to keep cells from interfering with each other. High-directivity antennas, some needing switchable beams, will be needed. To satisfy aggressive cost constraints the antennas must use printed technology. At millimetrewave frequencies the losses in the beamforming networks of conventional printed arrays are a limiting factor. Transmitarray and planar holographic antennas use printed technology but dispense with the beamforming networks. I will advance my research on transmitarrays by using the shaped fragmented element approach (which we have successfully used in reflectarray work) to design multifocal transmitarrays (enabling switched beams) and multiband transmitarrays (operating at widely separated multiple frequencies). Planar holographic antennas can be made truly low profile (important in commercial applications), with the feed integrated onto the substrates supporting the hologram, but have suffered from low aperture efficiencies. We will use the extended electromagnetic modelling abilities we have developed to synthesize feeding arrangements to improve this aperture efficiency.***