Cryogenic Calibration Setup for Broadband Complex Impedance Measurements

摘要

Reflection measurements give access to the complex impedance of a material ona wide frequency range. This is of interest to study the dynamical propertiesof various materials, for instance disordered superconductors. Howeverreflection measurements made at cryogenic temperature suffer from thedifficulty to reliably subtract the circuit contribution. Here we report on thedesign and first tests of a setup able to precisely calibrate in situ thesample reflection, at 4.2 K and up to 2 GHz, by switching and measuring, duringthe same cool down, the sample and three calibration standards.