High-Tc superconducting coplanar fractal slow-wave resonator

Summary form only given. Conductor losses in conventional conductors have constrained the miniaturisation of microwave passive circuits. High-Tc superconductors with an inherently low loss exhibit a great potential of overcoming this problem. The microwave properties of a novel superconducting transmission line with a very low phase velocity was investigated by using the coplanar resonator. This resonator was made using a three strip coplanar waveguide, loaded with a series of capacitive sections on both sides of the centre strip. The capacitive loadings are composed of a series of 20 μm wide open-end coplanar lines which are arranged into a compact area in a fractal structure. A 0.095 velocity reduction was obtained, when the resonator was cooled down to 17 K. The unloaded Q-value is over 8000 at 1.9 GHz