IEC 61788-7:2002

INTERNATIONAL IEC
STANDARD
61788-7
First edition
2002-01
Superconductivity –
Part 7:
Electronic characteristic measurements –
Surface resistance of superconductors
at microwave frequencies
Supraconductivité –
Partie 7:
Mesures des caractéristiques électroniques –
Résistance de surface des supraconducteurs
aux hyperfréquences
Reference number
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INTERNATIONAL IEC
STANDARD
61788-7
First edition
2002-01
Superconductivity –
Part 7:
Electronic characteristic measurements –
Surface resistance of superconductors
at microwave frequencies
Supraconductivité –
Partie 7:
Mesures des caractéristiques électroniques –
Résistance de surface des supraconducteurs
aux hyperfréquences
 IEC 2002  Copyright - all rights reserved
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– 2 – 61788-7  IEC:2002(E)
CONTENTS
FOREWORD.3

INTRODUCTION.4

1 Scope.5

2 Normative references .5

3 Terms and definitions .5

4 Requirements .6

5 Theory and calculation equations .6
6 Apparatus.9
7 Measurement procedure.11
8 Precision and accuracy of the test method.15
9 Test Report .17
Annex A (informative) Additional information relating to clauses 1 to 8.18
Bibliography.25
Figure 1 – Configuration of a cylindrical dielectric rod resonator short-circuited at both
ends by two parallel superconductor films deposited on dielectric substrates.6
Figure 2 – Computed results of the u-v and W-v relations for TE mode .8
01p
Figure 3 – Configuration of standard dielectric rods for measurement of tan δ .8
Figure 4 – Schematic diagram of measurement equipment for temperature dependence
of R using a cryocooler .9
s
Figure 5 – Measurement apparatus for R .10
s
Figure 6 – Frequency response of dielectric resonator using sapphire (ε’ = 9,4) . 13
Figure 7 – Insertion attenuation IA, resonant frequency f
and half power bandwidth Δf, measured at T Kelvin .13
Figure 8 – Reflection scattering parameters (S and S ) .15
11 22
Figure 9 – Term definitions in Table.16
Figure A.1 – Schematic configuration of several measurement methods for the surface

resistance .19
Figure A.2 – Three types of dielectric resonators .20
Figure A.3 – The mode chart to design TE resonator short-circuited at both ends by
parallel superconductor films[11] .22
Figure A.4 – The mode chart to design TE resonator short-circuited at both ends by
parallel superconductor films[11, 12].23
Figure A.5 – Relationship between d and f of the TE resonator for ε’ of the
0 011
sapphire rod .23

61788-7 © IEC:2002(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
SUPERCONDUCTIVITY –
Part 7: Electronic characteristic measurements –

Surface resistance of superconductors at microwave frequencies

FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. The IEC collaborates closely with the International
Organization for Standardization (ISO) in accordance with conditions determined by agreement between the
two organizations.
2) The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, an
international consensus of opinion on the relevant subjects since each technical committee has representation
from all interested National Committees.
3) The documents produced have the form of recommendations for international use and are published in the form
of standards, technical specifications, technical reports or guides and they are accepted by the National
Committees in that sense.
4) In order to promote international unification, IEC National Committees undertake to apply IEC International
Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this International Standard may be the subject
of patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 61788-7 has been prepared by IEC technical committee 90:
Superconductivity.
The text of this standard is based on the following documents:
FDIS Report on voting
90/111/FDIS 90/117/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives.
Annex A is for information only.
The committee has decided that the contents of this publication will remain unchanged until
2006. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
A bilingual version of this standard may be issued at a later date.

– 4 – 61788-7  IEC:2002(E)
INTRODUCTION
Since the discovery of some Perovskite-type Cu-containing oxides, extensive R & D work on

high-temperature oxide superconductors has been, and is being, made worldwide, and its

application to high-field magnet machines, low-loss power transmission, electronics and many

other technologies is in progress.

In various fields of electronics, especially in telecommunication fields, microwave passive

devices such as filters using oxide superconductors are being developed and are undergoing

on-site testing [1,2] .
Superconductor materials for microwave resonators, filters, antenna and delay lines have the
advantage of very low loss characteristics. Knowledge of this parameter is of primary
importance for the development of new materials on the supplier side and for the design of
superconductor microwave components on the customer side. The parameters of
superconductor materials needed for the design of microwave components are the surface
resistance R and the temperature dependence of the surface resistance.
s
Recent advances in high Tc superconductor (HTS) thin films with R several orders of
s
magnitude lower than that of normal metals have increased the need for a reliable
characterization technique to measure this property [3,4]. Traditionally, the R of Nb or any
s
other low temperature superconducting material was measured by first fabricating an entire
three dimensional resonant cavity and then measuring its Q-value. The R could be calculated
s
by solving the EM field distribution inside the cavity. Another technique involves placing a
small sample inside a larger cavity. This technique has many forms but usually involves the
uncertainty introduced by extracting the loss contribution due to the HTS films from the
experimentally measured total loss of the cavity.
The best HTS samples are epitaxial films grown on flat crystalline substrates and no high
quality films have been grown on any curved surface so far. What is needed is a technique
that: can use these small flat samples; requires no sample preparation; does not damage or
th
change the film; is highly repeatable; has great sensitivity (down to 1/1000 the R of
s
copper); has great dynamic range (up to the R of copper); can reach high internal powers
s
with only modest input powers; and has broad temperature coverage (4,2 K to 150 K).
The dielectric resonator method is selected among several methods [5,6,7] to determine the
surface resistance at microwave frequencies because it is considered to be the most popular
and practical at present. Especially, the sapphire resonator is an excellent tool for measuring
the R of HTS materials [8].
s
The test method given in this standard can be also applied to other superconductor bulk
plates including low Tc material.

This standard is intended to provide an appropriate and agreeable technical base for the time
being to engineers working in the fields of electronics and superconductivity technology.
The test method covered in this standard is based on the VAMAS (Versailles Project on
Advanced Materials and Standards) pre-standardization work on the thin film properties of
superconductors.
———————
Numbers in brackets refer to the bibliography.

61788-7 © IEC:2002(E) – 5 –
SUPERCONDUCTIVITY –
Part 7: Electronic characteristic measurements –

Surface resistance of superconductors at microwave frequencies

1 Scope
This part of IEC 61788 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 R at the resonant frequency.
s
The applicable measurement range of surface resistances for this method is as follows:
–Frequency: 8 GHz < f < 30 GHz
– Measurement resolution: 0,01 mΩ at 10 GHz
The surface resistance data at the measured frequency, and that scaled to 10 GHz, assuming

the f rule (f < 30 GHz) for comparison, shall be reported.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60050-815, International Electrotechnical Vocabulary – Part 8
...