基于非谐振节点的盒型拓扑结构基片集成波导滤波器设计

针对微波带通滤波器小型化、高性能的应用需求，提出使用单模和双模基片集成波导谐振器相结合设计广义切比雪夫带通滤波器.该结构可实现盒型拓扑结构，并且双模基片集成波导谐振器中的主模TE₁₀₁作为非谐振节点提供一条额外的交叉耦合路径，并能增加一个有限的传输零点；该结构不需要传统负耦合结构就能实现两个有限传输零点，并且该传输零点可以位于通带上方或下方，具有设计灵活的特点.为了进一步提高滤波器的选择性，研究了在四阶滤波器上蚀刻互补开环谐振器设计拓展的盒型拓扑结构滤波器，并实现五阶滤波功能三个有限传输零点.为了验证结构的合理性，设计了两款中心频率为10GHz的对称和非对称响应的四阶滤波器、一款中心频率为5.8GHz的五阶滤波器，并给出相应的含非谐振节点的盒型拓扑结构耦合矩阵进行验证，最后进行加工和测试.耦合矩阵响应、仿真和测试结果一致性较好，表明了该结构设计高性能滤波器的可行性.

Design of Substrate Integrated Waveguide Filters in Box-Like Topology with Nonresonating Node

Bandpass filters (BPFs) with generalized Chebyshev response using dual-and single-mode substrate integrated waveguide (SIW) resonators are proposed according to the miniaturization and high performances.The box-like topology with an additional cross-coupled path realized by the fundamental mode (TE₁₀₁) of the dual-mode SIW cavity is proposed,and an additional transmission zero (TZ) is achieved.The traditional negative coupling structure is not required in the proposed structure,and two TZs can be realized;moreover,the structure has flexible responses that two TZs can be located on the lower and/or upper of passband.To improve the selectivity,a complementary split-ring resonator (CSRR) etched into the fourth-order SIW filter to design a filter with an extended box-like topology is studied,and the fifth-order filtering function with three finite TZs can be realized.To verify the feasibility,a symmetric and an asymmetric response fourth-order BPFs with center frequency of 10GHz and a fifth-order BPF with center frequency of 5.8GHz are designed.The corresponding coupling matrixes of box-like topologies with nonresonating node (NRN) are also given to verify the proposed structure.Finally,the designed SIW BPFs are processed and measured.The responses of coupling matrixes,simulated and measured results are in good agreement,which demonstrates the feasibility of designed filters with high performances using the proposed structures.