This study presents a simple switched-band impedance transformer using microstrip lines. The proposed circuit is suitable for loads with frequency-dependent complex impedances at two arbitrary operating frequencies. The transformer comprises two cascaded microstrip lines and two detachable shunt stepped-impedance stubs, which are separately connected to the main line via switching diodes such that provide good matching at one of the two operating frequencies and suppress unwanted signal at the other frequencies. The structure contains several user-set parameters such that designers can create a smaller circuit. The circuit parameters, except the user-set ones, are obtained using the derived design formula. The numerical simulations and experimental results agree well such that validate the proposed structure and the design formula.

中文翻译：

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一种用于频变复杂负载的微带开关频带阻抗变压器

本研究提出了一种使用微带线的简单开关频带阻抗变压器。所提出的电路适用于在两个任意工作频率下具有与频率相关的复阻抗的负载。该变压器包括两条级联的微带线和两条可拆卸的分流步进阻抗短截线，它们通过开关二极管分别连接到主线路，从而在两个工作频率之一提供良好的匹配，并在其他频率抑制不需要的信号。该结构包含几个用户设置的参数，以便设计人员可以创建更小的电路。电路参数，除了用户设置的参数，是使用导出的设计公式获得的。数值模拟和实验结果非常吻合，从而验证了所提出的结构和设计公式。