High-Sensitivity Microwave Technique for Measuring Dielectric Loss in Coplanar Waveguide Resonators

Future quantum devices will require low-loss dielectric materials to enhance their performance. Traditionally, microwave loss of bulk materials is measured in high-quality-factor 3D cavities or planar resonator structures.

In this work, we present a general formalism for calculating both the participation ratio and loss tangent of an arbitrary load attached to a coplanar waveguide resonator. This method enables highly sensitive measurements of microwave properties in both conventional and novel dielectric materials, regardless of their dimensionality.

As a demonstration, we extract the dielectric constants and loss tangents of various van der Waals (vdW) dielectrics, comparing the results to those of materials commonly used in cutting-edge superconducting quantum devices.