Quality factor and intermodulation product of superconducting coplanar wave guides with slots in a DC magnetic field

Superconducting coplanar wave guides may easily be fabricated and combined with surface mounted semiconductor devices. The current density distribution is calculated to determine the microwave losses for different miniaturised cross sections and edge shapes. The calculated and measured quality factors are in good agreement at low power and zero external magnetic field perpendicular to the film. The influence of moats or slots in the CPW stripes on the measured quality factor and intermodulation product as a function of the external magnetic field is discussed in terms of critical superconducting current density.