Surface loss simulations of superconducting coplanar waveguide resonators

Losses in superconducting planar resonators are presently assumed to predominantly arise from surface-oxide dissipation, due to experimental losses varying with choice of materials. We model and simulate the magnitude of the loss from interface surfaces in the resonator and investigate the dependence on power, resonator geometry, and dimensions. Surprisingly, the dominant surface loss is found to arise from the metal-substrate and substrate-air interfaces. This result will be useful in guiding device optimization, even with conventional materials.