Miniaturized Dual-Mode Substrate Integrated Waveguide Bandpass Filters With Wide Stopbands Using Mixed-Mode Cavities

作者：Meng Ru Jiao, Long Sun, Xin Zhao, Fang Zhu, Weiliang Yu, Peng Chu, Kang Zhou, Guo Qing Luo · 发表于：IEEE Transactions on Microwave Theory and Techniques · 年份：2025 · DOI：10.1109/tmtt.2025.3580748 · 被引用次数：2 · 研究领域：Microwave Engineering and Waveguides、Semiconductor Lasers and Optical Devices、Photonic and Optical Devices

This article presents, for the first time, a novel class of miniaturized dual-mode substrate integrated waveguide (SIW) bandpass filters (BPFs) with wide stopbands using mixed-mode cavities (MMCs). The proposed MMCs uniquely support TEM, TE, and folded TE (FTE) modes simultaneously. By exploiting the TE101and FTE101modes as resonant modes and the TEM100mode as a nonresonanting mode, a dual-mode resonator (doublet) exhibiting two poles and two transmission zeros (TZs) is realized. A detailed characterization of the MMCs is provided. Subsequently, a class of miniaturized four-pole SIW BPFs with two flexible TZs is proposed, employing one dual-mode and two single-mode MMCs. By strategically staggering the spurious resonances of the dual- and single-mode MMCs, enhanced stopband performance is achieved. To validate the proposed concept, a four-pole BPF with quasi-elliptic response and two four-pole BPFs with asymmetric responses are designed, fabricated, and measured. The measured results agree well with the simulated ones.