MM-wave surface resistance measurements of HTS films using a highly sensitive cavity

Abstract

For the precise measurement of surface resistance of HTSs (high-temperature superconductors), a systematic design theory for truncated cone cavities is given. This kind of cavity avoids mode degeneration, which is a problem if cylindrical cavities are used. Also, if offers a considerably higher sensitivity with regard to surface resistance measurements. A measurement system at 52 GHz is described and results for three samples are given. The residual resistances of the three films were in the range of 5 m Omega to 10 m Omega at 52 GHz. A measurement accuracy of +or-0.5 m Omega has been achieved.<>