This article presents a novel class of dual-mode substrate-integrated waveguide (SIW) bandpass filters exploiting perturbed SIW rectangular cavities. By introducing metallized via-holes along the central line of an SIW rectangular cavity, the resonant frequency of TE ₁₀₁ mode can be shifted close to that of TE ₂₀₁ mode, thus creating a dual-mode resonator. This structure implements a doublet, which provides two poles and one or two transmission zeros (TZs). The pass bandwidth, spurious-free bandwidth, and positions of the TZs can be fully controlled by modifying the length of the perturbation, the side ratio of the rectangular cavity, and the offset of the input/output ports, respectively. Eight two-pole SIW filters are designed and investigated to demonstrate the high design flexibility. Moreover, a four-pole SIW filter with the asymmetric response and a five-pole SIW filter with quasi-elliptic response are designed, fabricated, and measured to describe the extension of the proposed approach to higher order filters.

中文翻译：

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使用扰动基板集成波导矩形腔的平面双模带通滤波器

本文介绍了一类新型的双模基板集成波导 (SIW) 带通滤波器，它利用了扰动的 SIW 矩形腔。通过沿 SIW 矩形腔的中心线引入金属化通孔，TE ₁₀₁模式的谐振频率可以移动到接近 TE ₂₀₁的谐振频率 模式，从而创建双模式谐振器。这种结构实现了双峰，它提供了两个极点和一个或两个传输零点 (TZ)。通过分别修改扰动的长度、矩形腔的边长比和输入/输出端口的偏移，可以完全控制通过带宽、无杂散带宽和 TZ 的位置。设计并研究了八个两极 SIW 滤波器，以证明其高度的设计灵活性。此外，设计、制造和测量了具有非对称响应的四极 SIW 滤波器和具有准椭圆响应的五极 SIW 滤波器，以描述所提出的方法对高阶滤波器的扩展。