Microwave nonlinearity measurements of epitaxial YBa2Cu3O7−x thin film by bridged resonator

A simple bridged resonator method is presented for microwave nonlinearity measurement of epitaxial superconductor thin film. By this method, microwave current is concentrated in local bridged part on the resonator, and local inductive and resistive nonlinearity in this part are measured. At the same time, undesired nonlinearity are eliminated from the tested results by the special current distribution of the resonator, which enhances the accuracy of the measured nonlinearity.