Superconductivity - Part 15: Electronic characteristic measurements - Intrinsic surface impedance of superconductor films at microwave frequencies

IEC 61788-15:2026 describes measurements of the intrinsic surface impedance (Zs) of HTS films at microwave frequencies by a modified two-resonance mode dielectric resonator method. The object of measurement is to obtain the temperature dependence of the intrinsic Zs at the resonant frequency f0.

The frequency and thickness range and the measurement resolution for the Zs of HTS films are as follows:

- frequency: up to 40 GHz;

- film thickness: greater than 50 nm;

- measurement resolution: 0,01 mΩ at 10 GHz.

It is crucial that the Zs data at the measured frequency, and that scaled to 10 GHz be reported for comparison, assuming the f2 rule for the intrinsic surface resistance, Rs (f < 40 GHz), and the f rule for the intrinsic surface reactance, Xs. This second edition cancels and replaces the first edition published in 2011. This edition constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous edition:

- informative Annex B, combined relative standard uncertainty in the intrinsic surface impedance is added;

- the terms, ‘precision and accuracy’, are replaced with uncertainty;

- results from a round robin