Superconducting coplanar microwave resonators with operating frequencies up to 50 GHz

TL;DR

This paper reports the development of superconducting niobium coplanar microwave resonators capable of operating up to 50 GHz, with high quality factors, suitable for high-frequency spectroscopy applications.

Contribution

The authors demonstrate high-frequency operation of superconducting resonators up to 50 GHz and optimize their design for improved performance at these frequencies.

Findings

Resonators operate up to 50 GHz with quality factors up to 25000.

Resonators detect superconducting transition of tin at multiple frequencies.

Resonators are fabricated from niobium on sapphire substrates.

Abstract

We demonstrate the operation of superconducting coplanar microwave resonators in a very large frequency range up to 50 GHz. The resonators are fabricated from niobium thin films on sapphire substrates and optimized for these high frequencies by small chip sizes. We study numerous harmonics of the resonators at temperatures between 1.5 K and 6 K, and we determine quality factors of up to 25000 at 1.5 K. As an example for spectroscopy applications of such resonators we detect the superconducting transition of a bulk tin sample at multiple probing frequencies.