A high-temperature superconductor (HTS) bandpass filter with special asymmetric cul-de-sac units (SACUs) is introduced and a compact low-radiating microstrip resonator is suggested for the filter realization. Such a filter is capable of providing better selectivity and higher out-of-band rejection and hence a decrease in adjacent-channel interference, which is of critical importance for mobile communication. This improvement of the filter characteristics results from an increase in the number of pairs of transmission zeros (TZs) on the imaginary axis on the complex plane when using the filter composed of the introduced SACUs, each providing a pair of TZs. An 11-pole filter consisting of two SACUs was fabricated using MgO substrate of 0.5 mm thickness with double-sided YBCO HTS film. Characterization of the filter at 77 K gave a central frequency of 2345 MHz, insertion loss 0.19 dB, an overall in-band return loss better than 15 dB, and an ultra-high band-edge steepness as a conse...

中文翻译：

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多对传输零点的特殊非对称小路单元配置高温超导滤波器的设计

介绍了一种具有特殊不对称死胡同单元（SACU）的高温超导体（HTS）带通滤波器，并提出了一种紧凑的低辐射微带谐振器来实现该滤波器。这种滤波器能够提供更好的选择性和更高的带外抑制能力，从而减少相邻信道干扰，这对移动通信至关重要。当使用由引入的SACU组成的滤波器（每个提供一对TZ）时，复平面上虚轴上的透射零对（TZ）数量增加，从而可以改善滤波器特性。使用厚度为0.5 mm的MgO衬底和双面YBCO HTS膜，制造了由两个SACU组成的11极滤波器。