Frequency-reconfigurable couplers presented before show some shortages such as limited tunable range and complex tuning mechanism. To address these problems, a frequency-reconfigurable coupler with wide tuning range is proposed based on a slotline structure. A T-shaped shorted feeding line with certain impedance transform is connected to each port of the coupler. Beneath the shorted end, the slotline structure is utilized to transfer the signal coupled from the feeding line. The 3-dB quadrature coupler performance is achieved by setting different widths of the slotlines. To tune the frequency, a varactor with tuning capacitance is loaded at the center of each shorted feeding line. Equivalent circuit is given by transmission line model to verify the design concept. For demonstration, the coupler is fabricated and measured. Good agreements between the simulation and measurement and a wide frequency tunable range from 1.2 to 2.6 GHz are achieved based on a single tuning mechanism.

中文翻译：

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具有宽调谐范围和简单调谐机制的基于槽线的频率可重构正交耦合器

之前提出的频率可重构耦合器存在一些不足，例如可调范围有限和调谐机制复杂。为了解决这些问题，提出了一种基于槽线结构的具有宽调谐范围的频率可重构耦合器。具有一定阻抗变换的T形短路馈线连接到耦合器的每个端口。在短路端下方，槽线结构用于传输从馈线耦合的信号。3-dB 正交耦合器性能是通过设置不同的槽线宽度来实现的。为了调谐频率，在每条短路馈线的中心加载一个带有调谐电容的变容二极管。等效电路由传输线模型给出以验证设计概念。为了演示，我们制造并测量了耦合器。