Wide-band Superconducting Coplanar Delay Lines

Research output: Contribution to journalArticlepeer-review

Colleges, School and Institutes


Two 25-ns high-temperature superconductor delay lines with novel double-spiral meander line structures were fabricated and measured, one based on the conventional coplanar waveguide (CPW) and the other based on the conductor-backed CPW. Compared with other published studies, the performance of the Conductor-backed CPW delay line is among the best in terms of the widest resonance-free band (2-18 GHz), low insertion loss (0.06 dB/ns at 60 K and 10 GHz), small ripple (<1 dB up until 16 GHz), and small dispersion (<2 ns in the variation of group delay between 2-18 GHz). This is also the first coplanar delay line successfully demonstrated without using wire bonding. The reflecting elements in the delay lines were identified through time-domain measurements. Full-wave simulations were performed to compare the double-spiral meander-line structure with conventional double-spiral line, and to identify the geometric factors restricting the bandwidth of the double-spiral meander line.


Original languageEnglish
Pages (from-to)2348-2354
Number of pages7
JournalIEEE Transactions on Microwave Theory and Techniques
Issue number7
Publication statusPublished - 1 Jul 2005


  • high-temperature superconductors (HTSs), delay lines, modeling, coplanar transmission lines