Measurement Of Microwave Surface Resistance Of High Temperature Superconducting Thin Films

This paper is one of the 863 projects.As the manufacture technology of high temperature superconductor (HTSC) film is greatly improved, it is applied more and more widely. Then it is becoming urgent to precisely measure the surface resistance of HTSC film that is one of the most important parameters of HTSC film. In this paper we will research the measurement in details.Sapphire resonator working in TE011+δ mode is used in this paper to nondestructively measure the microwave surface resistance RS of a single piece of HTS thin film at 77K.The microwave surface of HTSC film under test can be determined by measuring the change of the unloaded quality factors of the loaded resonator.Based on the others' research, a sapphire resonator working at 12GHz was improved and fabricated. The coupling of resonant circuit and the match of the outside circuit are analyzed. And the automatic test system is also built. The system features high sensitivity, good repeatability and nondestructive test. In this paper we also analyze the factors which will destroy the symmetry and bring forward some suggestion to reduce the nonsymmetry.