A miniature dual-band bandpass filter with interlocked stepped-impedance resonators (SIRs) is presented in this paper, which was designed for the student design competition held in European Microwave Week 2019. This bandpass filter is required to have two concurrent passbands, namely, the first passband at 900–1000 MHz and the second passband at 1427–1518 MHz bands, which cover six designated bands in sub-6 GHz range of fifth generation (5G) New Radio Access Technology. Three stopbands are required at 500–850, 1050–1350, and 1600–2000 MHz, respectively. To achieve the best figure of merit, an interlocked configuration of two SIRs is proposed. One advantage is that the impedance ratio of the inter-locked SIR can be controlled to have two passbands at the required frequencies. Second, the coupling section of the interlocked SIR gives three transmission zeros distributed to every stopbands such that the stopband suppression are dramatically enhanced. The measured results show that the passband insertion losses are 2.16 dB at the first passband and 1.33 dB at the second passband, and the return losses are greater than 10 dB. The stopband suppression at the transmission zeros are greater than 38 dB. The circuit is very compact as 41.40 × 19.96 mm2, equivalent to $0.25 \times 0.12\,\lambda _g^2$.

中文翻译：

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用于 5G 新无线接入技术的具有互锁步进阻抗谐振器的微型双频带带通滤波器设计

本文介绍了一种具有互锁步进阻抗谐振器 (SIR) 的微型双频带带通滤波器，它是为 2019 年欧洲微波周举行的学生设计竞赛而设计的。该带通滤波器需要有两个并发通带，即，第一个通带为 900-1000 MHz，第二个通带为 1427-1518 MHz，覆盖第五代 (5G) 新无线电接入技术的 6 GHz 以下范围内的六个指定频段。分别在 500–850、1050–1350 和 1600–2000 MHz 处需要三个阻带。为了获得最佳品质因数，提出了两个 SIR 的互锁配置。一个优点是可以控制互锁 SIR 的阻抗比，使其在所需频率具有两个通带。第二，互锁 SIR 的耦合部分给出了三个传输零点，分布在每个阻带上，从而显着增强了阻带抑制。实测结果表明，第一通带的通带插入损耗为2.16dB，第二通带为1.33dB，回波损耗大于10dB。传输零点处的阻带抑制大于 38 dB。电路非常紧凑，为 41.40 × 19.96 mm2， 相当于$0.25 \times 0.12\,\lambda _g^2$.