Cavity and ground effects on a superconducting microstrip resonator

Superconducting planar-transmission-line resonators play an increasingly important role in applications such as astronomical detection and circuit quantum electrodynamics. When measuring the transmission response of array resonators, however, one often observes some spurious resonances besides intrinsic ones. In this letter, effect cavity accommodating a half-wavelength superconducting microstrip resonator is investigated. An attenuation pole associated with resonance clearly observed found to be resulted from mutual coupling between cavity. addition, it demonstrated that adding ground layer for can avoid frequency shift owing ever-present thin air gap also improve Q factor resonator.