A Multiport Approach to Thermal Noise and Scattering Parameter Simulation of Cryogenic Experiments

TL;DR

This paper introduces a comprehensive algorithm for system-level thermal noise analysis in cryogenic experiments, effectively incorporating multiport device effects and temperature differentials, validated through ideal and real-world experiments.

Contribution

The paper presents a novel noise-wave based method for multiport thermal noise simulation that accounts for return loss, isolation, and temperature differences at cryogenic temperatures.

Findings

Method aligns with Friis cascade for ideal cases

Successfully simulates real cryogenic experiment data

Handles quantum noise limit conditions

Abstract

In this paper, a simple algorithm for detailed system-level thermal noise analysis is developed, demonstrated, and verified. This method uses noise-wave theory and noise covariance matrices to cascade noise and scattering parameters of multiport devices at different temperatures. This method addresses the effects of return loss, multiport isolation/coupling, and static temperature differentials between components, and will work in cases where the noise temperature is at or near the quantum noise limit. An ideal multidevice network will first be demonstrated to show that this method's results are consistent with the Friis cascade when component parameters such as return loss and isolation are ideal. Following the ideal multidevice example, a cryogenic experiment is conducted to demonstrate that the proposed simulation method is successful when real data are used.