SIDELOBE SUPPRESSION IN SMALL JOSEPHSON-JUNCTIONS

Many applications of Josephson junctions require that the sidelobes of the critical-current patterns as a function of magnetic field be as small as possible. The sidelobes can be significantly suppressed by appropriate choice of junction geometry. This paper emphasizes that suppression is not just a long-junction effect. For a wide variety of shaped small junctions, the diffraction patterns are given by simple expressions, inspection of which quickly shows the overall features of the patterns. For some shapes the highest sidelobes can be kept well under 1% of the central lobe. For applications requiring long junctions, the geometry of small junctions giving the desired pattern is a practical starting point for a long-junction analysis.