This paper presents a dual band bandpass filter by loading two semi‐circular mushroom resonators (ScMRs) inside the cavity of a circular substrate integrated waveguide (SIW). TM₁₀₁ and TM₂₀₁ modes of the mushroom resonator loaded circular SIW cavity are excited to generate the first and second passbands respectively. As the proposed bandpass filter is based on circular SIW cavity, the passbands of the filter undergo relatively low insertion loss (IL) compared to other referred works. The selectivity is improved by generating four transmission zeros (TZs); two TZs are generated in between the two passbands by cross coupling the excited modes of the resonators and other two TZs are generated in lower and upper stopband by the source to load coupling. The passbands of the proposed filter are centred at 2.24 GHz and 4.35 GHz with 13% and 6.2% fractional bandwidth (FBW) respectively. A prototype of the proposed dual bandpass filter occupying a compact area of 0.3λ₀ × 0.3λ₀ is fabricated in Rogers RT/Duroid 5880. The measured minimum insertion losses for the first and second passbands are 0.9 dB and 1.1 dB respectively with a good agreement observed between simulated and measured results.

中文翻译：

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基于半圆形蘑菇加载基片集成波导的双带通滤波器

本文介绍了一种通过将两个半圆形蘑菇形谐振器（ScMR）装入圆形衬底集成波导（SIW）的腔体内来实现的双带通滤波器。TM ₁₀₁和TM ₂₀₁蘑菇形谐振器加载的圆形SIW腔的振型被激发以分别产生第一和第二通带。由于拟议的带通滤波器基于圆形SIW腔，因此与其他相关工作相比，滤波器的通带经历了相对较低的插入损耗（IL）。通过产生四个透射零（TZ）来提高选择性。通过将谐振器的激励模式交叉耦合，在两个通带之间生成两个TZ，通过源极至负载耦合在上下阻带中生成另外两个TZ。所提出的滤波器的通带以2.24 GHz和4.35 GHz为中心，分别具有13％和6.2％的分数带宽（FBW）。所提出的双带通滤波器占据的0.3λ的紧凑区域A原型₀  ×0.3λ ₀ 用Rogers RT / Duroid 5880制造。在第一和第二通带上测得的最小插入损耗分别为0.9 dB和1.1 dB，在模拟结果和测量结果之间有很好的一致性。