HETERODYNE MICROWAVE MIXING IN A SUPERCONDUCTING YBA2CU3O7-X COPLANARWAVE-GUIDE CIRCUIT CONTAINING A SINGLE ENGINEERED GRAIN-BOUNDARY JUNCTION

The purpose of this work was to utilize the nonlinear current-voltage properties of induced grain boundaries in high temperature superconduc ting YBa2Cu3O7-x thin films to fabricate a planar microwave mixer. The experiment involved constructing a coplanar waveguide microwave circu it, the center conductor of which had a constriction patterned in it c ontaining a single high angle grain boundary, thus forming a weak link junction. Analysis was provided by use of the resistively shunted jun ction model with excess current.