Power handling capabilities of Y-Ba-Cu-O wafers and patterned microstrip resonators

Epitaxially grown large area YBa2Cu3O7-delta (YBCO) thin films are promisin g for the application in passive microwave devices (e.g. resonators, Alters , antennas). The main criteria for these applications are low microwave los ses and good power handling capabilities of the devices. Various measuremen t techniques are in use for the evaluation of the power handling capabiliti es of YBCO thin films. However, only few studies exist relating their resul ts to the actual performance of the microwave devices. We investigate the r f field dependence of the surface resistance of YBCO thin films using a di electric resonator technique at 8.5 GHz and 77 K. The lateral homogeneity o f the Alms with respect to the surface resistance is analyzed with an open resonator technique at 145 GHz and 77 K. Subsequently the films are pattern ed to microstrip resonators and their quality factors are measured at 4 GHz and 77 K as a function of the input r f power. The results show that the low values of the surface resistance and its cons tant level up to high rf magnetic fields similar to 10 mT are necessary req uirements but not stringent criteria for good power handling capability of the microstrip resonators.