An end-fed launcher geometry excited by a coaxially multiple-stepped coupling loop is proposed. The proposed configuration enables better performance in terms of a wider bandwidth and lower VSWR than previous works. In order to analyze and optimize the multiple-stepped coupling loop configuration, an accurate input impedance expression based on EMF method is presented. Numerical results of the proposed model and the results of previous works are compared, and verified by the experimental data. The input VSWRs were below 2 over the entire operating frequency band of the WR90 waveguide from 8.0 to 12.5 GHz. The fractional bandwidth of the end-fed launcher waveguide adapter involving single, double and triple-stepped coupling loop are 28.6%, 44.8% and 50.5%, respectively.

提出了一种由同轴多步耦合回路激励的末端馈送发射器的几何形状。与以前的工作相比，建议的配置在更宽的带宽和更低的VSWR方面实现了更好的性能。为了分析和优化多步耦合回路的配置，提出了一种基于EMF方法的精确输入阻抗表达式。比较了所提出模型的数值结果和以前的工作结果，并通过实验数据进行了验证。在8.0至12.5 GHz的WR90波导的整个工作频带上，输入VSWR均低于2。涉及单步，双步和三步耦合回路的最终馈送发射器波导适配器的分数带宽分别为28.6％，44.8％和50.5％。