SISMA: A Numerical Simulation Software for SIS Mixer Design

SISMA is a numerical simulation software programmed for the design of SIS mixers with single junction or junction arrays. It is based on quantum mixing theory and a proximation of the nonlinearity up to 2^nd harmonic. A new fixed-point iteration algorithm is designed to solve the large-signal nonlinear equation, which enables simulations of SIS mixers with distributed series-connected junction arrays, removing the limitation that only parallel-connected junction arrays can be simulated. The temperature and frequency-dependent complex surface impedances of various superconducting materials can be calculated in the simulation of thin-film superconducting passive components. The graphic interface of this software is a beneficial to fast optimization of the mixer circuit design.