Low Temperature Loss Measurement of Aluminium Thin Film Transmission Lines

Abstract

In this article, we study the planar microwave structures made from Aluminium thin films deposited by the sputtering technique at low temperature. The loss mechanisms in these Aluminium transmission lines deposited on Silicon substrates have been analysed by considering the stopping distance in the conducting lines. It is shown that the attenuation of the lines depends on the material properties and edge shape of the transmission lines. The two-port microwave transmission measurement of the structures was performed with a vector network analyser in the 1-12 GHz frequency range using a cryostat system. This work presents that Aluminium can be a potential candidate for various applications, namely MKIDS, and can replace other conventional superconductors for low temperature applications. Additionally, stopping distance analysis in silicon substrate-based microstrip lines can be continued in order to analyse the precise losses due to the step edge fabrication of the transmission lines. This analysis can then be used to estimate the uncertainty in the loss measurement. This work will be beneficial for developing the transmission lines for a variety of cutting-edge technologies, including quantum computing, the Internet of Things, and high-speed communication systems, where loss parameters play a crucial role.