Vv. Talanov et al., Measurement of the absolute penetration depth and surface resistance of superconductors using the variable spacing parallel plate resonator, IEEE APPL S, 9(2), 1999, pp. 2179-2182
We have developed a modified Parallel Plate Transmission Line Resonator wit
h a smoothly variable thickness of the dielectric spacer filled by liquid n
itrogen. A cryogenic linear stage is made to vary the spacer from 200 mu m
down to contact with 0.1 mu m resolution. Estimates of the absolute penetra
tion depth and the surface resistance are based on the analysis of the spac
er thickness dependencies of the resonator frequency and Q-factor, The meas
urements are performed at fixed temperature (77 K), so the result does not
depend on an a priori model for the temperature dependence of the penetrati
on depth. The ability of this technique to be employed as a standard for ch
aracterization of HTS films for microwave applications is pointed out.