Investigation of MW characteristics of HTS microstrip and coplanar resonators with ferrite thin-film components

Formulas for calculating the magnetic-field dependence of the resonance frequency and the quality factor of HTS microstrip (MS) and coplanar-waveguide resonators with a tangentially magnetized ferrite film component were obtained within the framework of the perturbation method. The conditions of attaining the maximum magnetic tuning effect of the resonance frequency (with reference to the external magnetic-field strength, the field-orientation angle, and the ferrite film position in the resonator) were determined and verified in the example of model resonators, formed from copper MS and ground-plane electrodes, a yttrium-iron-garnet (YIG) ferrite film component, and dielectric spacers. A YBCO MS resonator with a YIG component was also prepared and its characteristics were measured at 77 K.