Journal
IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY
Volume 28, Issue 1, Pages -Publisher
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC
DOI: 10.1109/TASC.2017.2773836
Keywords
Microstrip; NbTi; Superconducting cables; Superconducting microwave devices
Funding
- Japanese Society for the Promotion of Science-JSPS [26220704]
- National Science Foundation-NSF (ATI) [AST-1308556]
- National Aeronautics and Space Administration-NASA [NNX16AE98G]
- Direct For Mathematical & Physical Scien [1308556] Funding Source: National Science Foundation
Ask authors/readers for more resources
Large arrays of superconducting devices such as microwave kinetic inductance detectors require high density interconnects from higher temperatures with minimal heat load, low loss, and negligible crosstalk capable of carrying large and overlapping bandwidth signals. We report the fabrication of superconducting 53 wt% Nb-47 wt% Ti (Nb-47Ti) microstrip transmission lines laminated onto flexible polyimide substrates with lengths up to 40 cm and up to ten traces. The 50 Omega traces terminate in G3PO coaxial push-on connectors. We found transmission losses of 2.5 dB and a nearest-neighbor forward crosstalk of -25 dB at 8 GHz on a typical 5 trace, 1.8-cm-wide, 0.198-mm-thick, 22-cm-long flex cable at 30 mK. A simple two-port analytical model and subsequent Sonnet simulations indicate that this loss is mainly due to a complex impedance mismatch from wirebonds at the end connector without which the insertion loss would be <2.7 dB/m. This is about six times worse than the transmission measured in Coax Company, Ltd.'s smallest (circle divide 0.86 mm) Nb-47Ti coaxial cables, possibly from differences in the low temperature loss properties of polyimide laminates versus PTFE or from unaccounted resistive losses in the copper adapter coaxes of our tested device. Heat flow calculations from literature data show that the 0.198-mm-thick flex cables tested have roughly equivalent thermal conductance per trace below 4 K compared to the circle divide 0.86 mm Nb-47Ti coaxial cables.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available