Simulation of flux-pumped Josephson parametric amplifier with a detailed SQUID model using harmonic balance method

Abstract

Abstract This work presents an analysis of flux-pumped Josephson Parametric Amplifier (JPA) with a detailed Superconducting QUantum Interference Device (SQUID) model, using Harmonic Balance (HB) method in Keysight Advanced Design System (ADS). The model is built with the generalized Resistively Shunted Junction (RSJ) model of a Josephson junction and the quantization condition of a SQUID, incorporating effects of the geometric inductance and parasitic parameters. This model is used to simulate the behavior of an unmatched lumped element JPA and an impedance-matched JPA, showing the necessity of the detailed SQUID model for the simulation of a broadband JPA by comparison with the results based on a widely used simplified model. Gain profiles obtained from the approach are consistent with the existing experiments in literatures within reasonable accuracy. Owing to the HB method, the simulation is of high efficiency, making it feasible to sweep and optimize parameters. This provides a fast and accurate method for the design and analysis of a JPA.