There is considerable interest world-wide in high temperature superconductor (HTS) microwave devices because microwave losses in HTS devices are far lower than those in equivalent devices fabricated from conventional materials, such as copper. For example, the surface resistance, R_s, at 10 GHz has been shown to be over a hundred times smaller in high quality YBa_2Cu_3O_(7-x) (YBCO) thin films than in copper at 77K. This low R_s has led to the development of a wide range of planar resonant structures that have sharply defined resonant frequencies, and also to the miniaturisation of devices such as microwave filters (2).
展开▼
