Structures for the Measurement of High-Frequency Properties of Point-Contact Josephson Junctions

Others have demonstrated that superconductor point-contact Josephson junctions interact with electromagnetic fields having free-space wavelengths as short as several hundred microns. To lay a theoretical foundation for more quantitative measurements of junction properties, we have undertaken an analysis of electromagnetic properties of three closed point-contact structures and have computed how those structures influence a point-contact junction described by a simple but plausible model. The analysis is in part an exercise in antenna theory; the conductors, superconductors, and dielectrics making up the structure act as an antenna for the intrinsically nonlinear Josephson junction.