Cross-coupled YBCO BPFs with wide upper stopband using quarter-wavelength stepped-impedance resonators

Chung I.G. Hsu, Li Ming Wang, Li Shian Chen, Ching Her Lee

Research output: Contribution to journalArticle

3 Citations (Scopus)


This paper presents a cross-coupled high-temperature superconducting (HTS) bandpass filter (BPF) design using quarter-wavelength stepped-impedance resonators (λ/4 SIRs) for the wireless communication applications. A pair of transmission zeros associated with the cross-coupled configuration is designed to be placed near the passband skirts, greatly sharpening the rolling-off at the passband edges. The spurious-passband center frequency of the BPF using λ/4 SIRs is simulated to be higher than that of the BPF adopting λ/2 SIRs. A BPF using λ/4 SIRs, conceived to be smaller than the corresponding BPF using λ/2 SIRs, has been fabricated by double-sided depositing patterned YBCO film on a 10-mm-square and 0.5-mm-thick LaAlO3 substrate and by putting them in a copper housing. The measured results revealed that this BPF has a very wide stopband bandwidth beyond the desired passband.

Original languageEnglish
Pages (from-to)273-280
Number of pages8
JournalChinese Journal of Physics
Issue number2 II
Publication statusPublished - 2007 Apr 1

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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