Study of high temperature superconducting thin film with application in microwave circuits

In this paper, a numerical solution to the estimation of superconducting thin film surface impedance is presented. Integral equations are developed in the basis of Maxwell equation, Green function and two-fluid model. The solution of the integral equations gives the surface impedance of the superconducting thin film, which can be used in many applications in microwave circuits. It is found that the thin film surface impedance at microwave frequency dependent on the thickness of the substrate. A comparison with published experimental results for surface resistance is included to check the accuracy of this technique. The interaction of superconducting thin film with surface acoustic wave (SAW) in hybrid layer structure is studied as one application in microwave circuits. It is found that the attenuation of SAW is dependent on frequency and gives great change at the temperature transition to normal region.