A coplanar waveguide filter using thin-film high temperature superconductor

The design of a coplanar waveguide low-pass filter mode of high-critical-temperature superconducting YBCO film on a LaAlO/sub 3/ substrate is described. The patterned and packaged coplanar waveguide low-pass filter of YBCO exhibited measured insertion losses in liquid nitrogen superior to the loss of similar thin-film copper filter throughout the 0-to-9.5-GHz passband. Coplanar waveguide models for use with thin-film normal metal (with thickness either greater or less than the skin depth) and YBCO are discussed and used to compare the losses of the measured YBCO and copper circuits.<
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