A novel dual‐mode optimized patch capacitor loaded T‐type resonator is proposed for the design of a dual‐band filter (DBF). The resonator has its lowest even‐ and odd‐mode at the two expected passband frequencies and the first spurious mode far away from the passbands. For tuning of the two sets of coupling strengths for both passbands, open/shorted secondary coupling structures are introduced as a fine‐tuning coupling structure to increase/decrease the primary coupling strength. A four‐pole DBF with passbands centered at 2450 and 3500 MHz, respectively, is proposed and fabricated using the HTS material. The measured results of the filter indicate superior performance and good fitting with the simulation results. The return losses of both passbands and the insertion losses obtained by measurements are greater than 14 dB and less than 0.3 dB, respectively. The stopband rejection exceeds 50 dB up to 8.0 GHz.

中文翻译：

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具有微调耦合结构的紧凑型双频超导滤波器

提出了一种新型的双模式优化的贴片电容器负载T型谐振器，用于双频带滤波器（DBF）的设计。谐振器在两个预期的通带频率处具有最低的偶数模式和奇数模式，而远离通带的第一个杂散模式。为了调整两个通带的两组耦合强度，引入了开/短路次级耦合结构作为微调耦合结构，以增加/减小初级耦合强度。提出并使用HTS材料制造了通带分别位于2450和3500 MHz中心的四极DBF。滤波器的测量结果表明性能优越，并且与仿真结果非常吻合。两个通带的回波损耗和通过测量获得的插入损耗均大于14 dB且小于0.3 dB，分别。在8.0 GHz时，阻带抑制超过50 dB。