A novel method for designing a multiband rat‐race ring coupler based on a notch filter is proposed. This method realizes dual‐, tri‐, quad‐, penta‐, … band characterizes of coupler using the same structure, two additional branches. So, it has three advantages: (a) simple structure even the number of working bands more than four; (b) achieving the different numbers of working bands with just one structure; (c) useful for almost any kind of wideband passive components because it views them as black boxes. Three prototypes, a tri‐band ring coupler (Global System for Mobile Communications 0.9 GHz, Digital Communication System 1.8 GHz, Industrial Scientific Medical 2.45 GHz), a quad‐band ring coupler (Time Division Long‐Term Evolution 2.3 GHz, Satellite C‐Band Downlink 3.8 GHz, Aeronautical Radio Navigation 4.3 GHz, and Satellite C‐Band Uplink Applications 6.3 GHz) and a penta‐band ring coupler (Frequency Division Long‐Term Evolution [LTE‐FDD] 0.9, 1.4, 1.8, 2.3, and 2.6 GHz), are simulated and measured. They all use the same structure but different parameters of the added branch. The results validate the functionality of the coupler. The method of designing multiband devices in this study can be used for other passive devices, and the structure is simple.

中文翻译：

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基于陷波滤波器的新型多频带环形耦合器

提出了一种基于陷波滤波器设计多频带鼠环耦合器的新方法。这种方法使用相同的结构和两个额外的分支来实现耦合器的双，三，四，五，……频段表征。因此，它具有三个优点：（a）结构简单，即使工作频带超过四个。（b）仅用一种结构就可以实现不同数量的工作频带；（c）对几乎所有类型的宽带无源组件都有用，因为它将它们视为黑匣子。三个原型，一个三频段环形耦合器（全球移动通信系统0.9 GHz，数字通信系统1.8 GHz，工业科学医学2.45 GHz），一个四频段环形耦合器（时分长期演进2.3 GHz，卫星C-频段下行链路3.8 GHz，航空无线电导航4.3 GHz，模拟和测量了卫星和C频段上行链路应用6.3 GHz和五频段环形耦合器（频分长期演进[LTE-FDD] 0.9、1.4、1.8、2.3和2.6 GHz）。它们都使用相同的结构，但所添加分支的参数不同。结果验证了耦合器的功能。本研究中设计多频带器件的方法可以用于其他无源器件，并且结构简单。