Optimizing the performance of cryogenic quantum amplifiers is a key step toward achieving high-fidelity and scalable qubit readout. In this work, we present efficient and accurate modeling of a Josephson traveling-wave parametric amplifier (JTWPA) based on electromagnetic (EM) and circuit co-simulation. In contrast to conventional simulation methods where an equivalent lumped-element circuit model of the JTWPA is required, we directly perform full EM analysis of the device to faithfully determine the linear response. The extracted S-parameters are then fed into a nonlinear harmonic balance simulator with Josephson junctions represented as circuit elements. The simulated linear and gain properties are compared with experimental results and show good agreement.
@article{arxiv.2509.07807,
title = {Modeling Josephson traveling-wave parametric amplifiers with electromagnetic and circuit co-simulation},
author = {Likai Yang and Jennifer Wang and Mohamed Awida Hassan and Philip Krantz and Kevin P. O'Brien},
journal= {arXiv preprint arXiv:2509.07807},
year = {2025}
}