Guided modes excited by a current source in a multilayer cylindrical structure is thoroughly investigated. The guidance condition in the multilayer structure is formulated. Based on this, three antenna configurations in cylindrical stratified media that are of strong practical interest are rigorously investigated: viz. a monopole antenna, a conformal axially-directed slot antenna and an azimuthal slot antenna in a cylindrical layered medium. While previous treatments of such configurations did not investigate the mode-excitation problem of antennas in stratified cylindrical media and were limited in their applicability for a dipole antenna in a cylindrical medium or assumed the slot-current distribution for a slot antenna over a conducting cylinder only, the current investigation provides an in-depth and rigorous insight to the modes excited and power coupled to the excited modes for the antenna configurations and removes such restrictions. In addition to the efficient and rigorous investigation of the coupling problem for the three antenna structures, the radiation characteristics of the antenna configurations are also evaluated using the method of stationary phase, enabling a comprehensive treatment of the antenna structures from both the coupling and radiation aspects.

中文翻译：

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圆柱分层介质中天线的模式激励和辐射特性

深入研究了多层圆柱结构中由电流源激发的导模。制定了多层结构中的引导条件。在此基础上，严格研究了圆柱分层介质中的三个天线配置，这些配置具有很强的实用价值。圆柱形分层介质中的单极天线，共形轴向定向缝隙天线和方位缝隙天线。尽管先前对这种配置的处理并未研究分层圆柱介质中天线的模式激励问题，并且它们在圆柱介质中对偶极天线的适用性受到限制，或者仅假设了缝隙天线在导电圆柱体上的缝隙电流分布，当前的研究对天线配置的激励模式和耦合到激励模式的功率提供了深入而严格的见解，并消除了此类限制。除了高效，严格地研究三种天线结构的耦合问题之外，还使用固定相位方法评估了天线配置的辐射特性，从而可以从耦合和辐射方面对天线结构进行全面处理。