SuperMix: A Flexible Software Library for High-Frequency Circuit Simulation, Including SIS Mixers and Superconducting Elements

'SuperMix" is a software library written to aid in the calculation and optimization of the signal and noise performance of high -frequency circuits, especially those including superconductors and superconducting tunnel junctions. Using this library, C++ programs can be written to simulate circuits of arbitrary size, complexity, and topology. The library includes an optimizer which can minimize an arbitrary error function by varying chosen circuit parameters. Using SuperMix, it is now possible to directly optimize an SIS receiver design to minimize the average noise temperature across the desired RF frequency band. including a full harmonic balance analysis at every frequency. point together with a full analysis of the IF amplifier circuit and its noise contribution.