This letter presents a novel class of compact dual-mode bandpass filters based on half-mode substrate-integrated waveguide (HMSIW) cavities. By using both TE ₁₀₂ and TE ₃₀₁ modes of the HMSIW rectangular cavity as resonant modes and TE ₁₀₁ mode as nonresonating mode, a novel HMSIW doublet with two poles and two transmission zeros (TZs) is implemented. The TZs can be located at one side or both sides of the passband. Therefore, flexible responses can be obtained. A two-pole HMSIW filter with asymmetric response and a four-pole HMSIW filter with quasi-elliptic response have been designed, fabricated, and measured, to demonstrate and verify the proposed structure. Compared with substrate-integrated waveguide (SIW) counterparts, the dual-mode HMSIW filters have the advantage of smaller size.

中文翻译：

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基于半模基片集成波导腔的紧凑型双模带通滤波器

这封信提出了一种基于半模基片集成波导（HMSIW）腔的新型紧凑型双模带通滤波器。通过将HMSIW矩形腔体的TE ₁₀₂和TE ₃₀₁模式用作谐振模式和TE ₁₀₁模式作为非谐振模式，实现了一种新颖的具有两个极点和两个传输零点（TZ）的HMSIW双峰。TZ可以位于通带的一侧或两侧。因此，可以获得灵活的响应。设计，制造和测量了具有非对称响应的两极HMSIW滤波器和具有准椭圆响应的四极HMSIW滤波器，以演示和验证所提出的结构。与衬底集成波导（SIW）相比，双模HMSIW滤波器具有尺寸更小的优势。