WG 8 - TC 90/WG 8

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  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 test are added.

IEC 61788-17:2021 specifies the measurements of the local critical current density (Jc) and its distribution in large-area high-temperature superconducting (HTS) films by an inductive method using third-harmonic voltages. The most important consideration for precise measurements is to determine Jc at liquid nitrogen temperatures by an electric-field criterion and obtain current-voltage characteristics from its frequency dependence. Although it is possible to measure Jc in applied DC magnetic fields [20] [21], the scope of this document is limited to the measurement without DC magnetic fields. This technique intrinsically measures the critical sheet current that is the product of Jc and the film thickness d. The range and measurement resolution for Jcd of HTS films are as follows.
- Jcd: from 200 A/m to 32 kA/m (based on results, not limitation).
- Measurement resolution: 100 A/m (based on results, not limitation).

IEC 61788-7:2020 describes measurement of the surface resistance (Rs) of superconductors at microwave frequencies by the standard two-resonator method. The object of measurement is the temperature dependence of Rs at the resonant frequency. The applicable measurement range of Rs for this method is as follows:
- Frequency: 8 GHz  - Measurement resolution: 0,01 m Ω at 10 GHz
The Rs data at the measured frequency, and that scaled to 10 GHz, assuming the f 2 rule for comparison, is reported. This third edition cancels and replaces the second edition, published in 2006. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) informative Annex B, relative combined standard uncertainty for surface resistance measurement has been added;
b) precision and accuracy statements have been converted to uncertainty;
c) reproducibility in surface resistant measurement has been added.

IEC 61788-17:2013 describes the measurements of the local critical current density (Jc) and its distribution in large-area high-temperature superconducting (HTS) films by an inductive method using third-harmonic voltages. The most important consideration for precise measurements is to determine Jc at liquid nitrogen temperatures by an electric-field criterion and obtain current-voltage characteristics from its frequency dependence. Although it is possible to measure Jc in applied DC magnetic fields, the scope of this standard is limited to the measurement without DC magnetic fields. This technique intrinsically measures the critical sheet current that is the product of Jc and the film thickness d. The range and measurement resolution for Jcd of HTS films are from 200 A/m to 32 kA/m, with a measurement resolution of 100 A/m.

IEC 61788-16:2013 involves describing the standard measurement method of power-dependent surface resistance of superconductors at microwave frequencies by the sapphire resonator method. The measuring item is the power dependence of Rs at the resonant frequency. This method is the applicable for a frequency in the range of 10 GHz, for an input microwave power lower than 37 dBm (5 W). The aim is to report the surface resistance data at the measured frequency and that scaled to 10 GHz. Keyword: superconductivity

IEC 61788-15:2011 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.

IEC 61788-7:2006 describes measurement of the surface resistance of superconductors at microwave frequencies by the standard two-resonator method. The object of measurement is the temperature dependence of Rs at the resonant frequency. The applicable measurement range of surface resistances for this method is as follows:
- Frequency: 8 GHz  - Measurement resolution: 0,01 milliohm at 10 GHz.

Describes measurement of the surface resistance of superconductors at microwave frequencies by the standard two-resonator method. The object of measurement is the temperature dependence of Rs at the resonant frequency.