Lumped arrays of shunted bicrystal Josephson junctions

We report on the design, fabrication, and investigation of lumped arrays of Josephson junctions embedded into coplanar strip-lines (CPS). The arrays were incorporated into the CPS by meandering a bilayer across the grain boundary. Limitations on junctions packing density are discussed. The dependence of the length of the lumped array on spread of critical currents of junctions in the array was found. The investigated arrays with 431 junctions have shown frequency locking with an external irradiation. Voltage steps up to 20 mV at liquid nitrogen temperature were demonstrated.