Improvement of Image Method for Measuring the Microwave Surface Resistance of HTS Thin Film

A new device using image sapphire resonator method is introduced for measuring the microwave resistance of high temperature superconductor (HTS) thin films. Coupling hole was used in this device for the stimulation of resonator. A 6 mm×3 mm×8 mm dielectric waveguide, an L type coupling loop made of roasting silver situating in the section plane of the dielectric waveguide are used for the EM transmitting. This coupling structure is a new attempt for low temperature measurement. The microwave surface resistances (RS) of two YBCO films about 2 inches deposited on MgO substrates are measured.