Analysis of superconducting transmission-line structures for passive microwave device applications

A full-wave spectral-domain volume-integral-equation technique is used to calculate the complex propagation constant, the complex characteristic impedance, and the current distribution for Nb and YBa/sub 2/Cu/sub 3/O/sub 7-x/ microstrip lines and coplanar waveguides with superconducting ground planes. Measurements of resonant frequency and quality factor are performed on Nb microstrip and coplanar waveguide resonators, and the results are compared with numerical calculations. The power-handling capability of various superconducting transmission-line structures is calculated. Results of phase noise measurements on Nb microstrip resonators suggest that phase noise may be related to the current distribution in the structure.<
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