Coaxial Lines Containing Ceramic High‐T_c Superconducting‐Center Conductors

Abstract

A superconducting line should be essentially lossless and dispersionless and have a purely resistive impedance up to at least 10 GHz. In fact we expect that a long (>I km) line could carry nanosecond rise time pulses with zero distortion and low loss (<1 dBlkm). We have measured the losses in some short sections of coaxial line containing ceramic high-T, superconducting-center conductors over the frequency range from 5 to 50 M H z . There is only a slight improvement over a completely copper coaxial line. [

Corrosion of YBCO bulk superconductor in air

“…One of the important problems affecting the application of these superconductors is the tendency to irreversible degradation due to exposure to ambient atmospheric conditions . All families of HTS superconductors are susceptible to degradation by environmental agents, such as atmospheric moisture . Corrosion process is sensitive not only to environment but also to the microstructure of superconductor …”

Characterizing the attenuation of coaxial and rectangular microwave-frequency waveguides at cryogenic temperatures

“…Previous studies of the attenuation constant were performed for different types of superconducting coaxial cables down to 4 K by impedance matched measure-ments [24][25][26][27][28][29][30][31]. In those works, the attenuation constant is typically evaluated from measurements of the transmission spectrum of the waveguide, which is subsequently corrected for the attenuation in the interconnecting cables from room temperature to the cold stage in a reference measurement.…”