Compact wide stopband superconducting bandpass filter using modified spiral resonators with interdigital structure<xref rid="cpb_27_6_068502_fn1" ref-type="fn">*</xref><fn id="cpb_27_6_068502_fn1"><label>*</label><p>Project supported by the National Key Scientific Instrument and Equipment Development Project, China (Grant No. 2014YQ030975) and the National Natural Science Foundation of China (Grant Nos. 61371009 and 61401282).</p></fn>

Compact wide stopband superconducting bandpass filter using modified spiral resonators with interdigital structure**

Project supported by the National Key Scientific Instrument and Equipment Development Project, China (Grant No. 2014YQ030975) and the National Natural Science Foundation of China (Grant Nos. 61371009 and 61401282).

Wu Di¹, Wei Bin^{1, †}, Li Bo¹, Guo Xu-Bo¹, Lu Xin-Xiang², Cao Bi-Song¹

(color online) Simulated coupling coefficients for four types of coupling patterns sketched in Fig. 5.