A compact dual-band bandpass filter based on the substrate integrates suspended line platform is proposed in this letter. The design is implemented using low-cost FR-4 material, while the loss can be reduced by 3D metal connections with substrate cutout. 0.97 dB/1.6 dB improvement of insertion loss is achieved and verified at 3.45 GHz/4.9 GHz. By paralleling quarter wavelength step impedance resonators with different operating frequencies, two paths formed between source and load. Both bandwidth and location of transmission zeros can be adjusted independently. Two stubs are added working not only as feed structure but also as a stop band resonator, which can provide 20 dB out-of-band suppression up to 4.4f0. The obtained performances are good enough to compare with the state of art, though very low-cost FR-4 materials are used.

中文翻译：

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一种使用基板增强抑制的紧凑型低成本双带带通滤波器，集成了悬浮线技术

本文提出了一种基于基板集成悬线平台的紧凑型双带带通滤波器。该设计使用低成本的 FR-4 材料实现，而损耗可以通过具有基板切口的 3D 金属连接来减少。在 3.45 GHz/4.9 GHz 下实现并验证了插入损耗的 0.97 dB/1.6 dB 改善。通过并联具有不同工作频率的四分之一波长阶跃阻抗谐振器，在源和负载之间形成两条路径。传输零点的带宽和位置都可以独立调整。添加了两个短截线，不仅用作馈电结构，还用作阻带谐振器，可提供高达 4.4f0 的 20 dB 带外抑制。尽管使用了非常低成本的 FR-4 材料，但获得的性能足以与现有技术进行比较。