Ideally, the orthogonal port can be effective to eliminate the TE102/TE201 spurious passband of a fundamental substrate integrated waveguide (SIW) filter using the orthogonality. However, it was not feasible in practical applications because the orthogonality of TE102/TE201 is deteriorated by the orthogonal port. Here, we propose an approach to repair the orthogonality which makes the practical orthogonal port work as the ideal one and thereby avoid the TE102/TE201 spurious passband in an SIW filter. The repair is achieved using ports’ offset almost without affecting the fundamental passband. A guideline of using the proposed technique to design a wide stopband filter based on square SIW resonators is provided. Four SIW filters with three, four, five, and six resonators, respectively, are then experimented. The measured results agree with the expectations well. An empirical equation is finally given to initialize the critical ports’ offset to facilitate the design. Compared with counterparts, the proposed technique uses a much simpler design, obtains better performance, and can be more easily implemented in practical applications.

中文翻译：

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由正交端口偏移实现的宽阻带基板集成波导滤波器

理想情况下，正交端口可以有效地消除使用正交性的基片集成波导 (SIW) 滤波器的 TE102/TE201 杂散通带。但在实际应用中并不可行，因为正交端口会降低TE102/TE201的正交性。在这里，我们提出了一种修复正交性的方法，使实际的正交端口作为理想的端口工作，从而避免 SIW 滤波器中的 TE102/TE201 杂散通带。修复是通过使用端口偏移实现的，几乎不会影响基本通带。提供了使用所提出的技术设计基于方形 SIW 谐振器的宽阻带滤波器的指南。然后对分别具有三个、四个、五个和六个谐振器的四个 SIW 滤波器进行实验。测量结果与预期非常吻合。最后给出了一个经验方程来初始化关键端口的偏移量，以方便设计。与同行相比，所提出的技术使用更简单的设计，获得更好的性能，并且更容易在实际应用中实现。