Superconducting microwave resonators

The low surface resistance of high temperature superconductors enables the construction of resonators which have significantly higher Qs than equivalent resonators made out of conventional conductors. Resonators are widely used in microwave work in many different applications, and it is therefore important to assess the performance of different types of resonant device to ascertain the improvement which is possible for each particular type. Experimental results on four different resonators are reported here, the cylindrical cavity, coaxial cavity, helical cavity and a coplanar resonator. The resonators have been constructed out of different high-temperature superconducting materials.