IEC 61726:1999

Cable assemblies, cables, connectors and passive microwave components - Screening attenuation measurement by the reverberation chamber method

Describes the measurement of screening attenuation by the reverberation, or stirred, chamber, suitable for virtually any type of microwave component and having no theoretical upper frequency limit. It is only limited toward low frequencies due to the size of the test equipment, which is frequency dependent and is only one of several methods of measuring sreening attenuation. For the purpose of this standard, examples of microwave components are waveguides, phase shifters, diplexers/multiplexers, power dividers/combiners, etc.

Câbles, cordons, connecteurs et composants hyperfréquence passifs - Mesure de l'atténuation d'écran par la méthode de la chambre réverbérante

Describes the measurement of screening attenuation by the reverberation, or stirred, chamber, suitable for virtually any type of microwave component and having no theoretical upper frequency limit. It is only limited toward low frequencies due to the size of the test equipment, which is frequency dependent and is only one of several methods of measuring sreening attenuation. For the purpose of this standard, examples of microwave components are waveguides, phase shifters, diplexers/multiplexers, power dividers/combiners, etc.

General Information

• Status: Published
• Publication Date: 29-Nov-1999
• ICS: 33.120.10 - Coaxial cables. Waveguides
• ICS: 33.120.30 - RF connectors
• Technical Committee: SC 46A - Coaxial cables
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 08-Sep-2015

Relations

• Revised: IEC 61726:2015 - Cable assemblies, cables, connectors and passive microwave components - Screening attenuation measurement by the reverberation chamber method
• Effective Date: 05-Sep-2023

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD
Second edition
1999-11
Cable assemblies, cables, connectors
and passive microwave components –
Screening attenuation measurement
by the reverberation chamber method
Câbles, cordons, connecteurs et composants
hyperfréquence passifs –
Mesure de l'atténuation d'écran par la méthode
de la chambre réverbérante
Reference number
Numbering
As from 1 January 1997 all IEC publications are issued with a designation in the
60000 series.
Consolidated publications
Consolidated versions of some IEC publications including amendments are
available. For example, edition numbers 1.0, 1.1 and 1.2 refer, respectively, to the
base publication, the base publication incorporating amendment 1 and the base
publication incorporating amendments 1 and 2.
Validity of this publication
The technical content of IEC publications is kept under constant review by the IEC,
thus ensuring that the content reflects current technology.
Information relating to the date of the reconfirmation of the publication is available
in the IEC catalogue.
Information on the subjects under consideration and work in progress undertaken
by the technical committee which has prepared this publication, as well as the list
of publications issued, is to be found at the following IEC sources:
• IEC web site*
•
Catalogue of IEC publications
Published yearly with regular updates
(On-line catalogue)*
• IEC Bulletin
Available both at the IEC web site* and as a printed periodical
Terminology, graphical and letter symbols
For general terminology, readers are referred to IEC 60050: International
Electrotechnical Vocabulary (IEV).
For graphical symbols, and letter symbols and signs approved by the IEC for
general use, readers are referred to publications IEC 60027: Letter symbols to be
used in electrical technology, IEC 60417: Graphical symbols for use on equipment.
Index, survey and compilation of the single sheets and IEC 60617: Graphical symbols
for diagrams.
* See web site address on title page.

INTERNATIONAL IEC
STANDARD
Second edition
1999-11
Cable assemblies, cables, connectors
and passive microwave components –
Screening attenuation measurement
by the reverberation chamber method
Câbles, cordons, connecteurs et composants
hyperfréquence passifs –
Mesure de l'atténuation d'écran par la méthode
de la chambre réverbérante
 IEC 1999  Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission 3, rue de Varembé Geneva, Switzerland
Telefax: [phone] e-mail: [e-mail] IEC web site http://www.iec.ch
Commission Electrotechnique Internationale
PRICE CODE
S
International Electrotechnical Commission
For price, see current catalogue

– 2 – 61726 © IEC:1999(E)
CONTENTS
Page
FOREWORD . 3
INTRODUCTION .5
Clause
1 Scope . 6
2 Basic description of the reverberation chamber method . 6
3 Measurement of the screening attenuation of the device under test (DUT) . 7
4 Description of the test set-up. 7
4.1 Reverberation chamber . 7
4.2 Mode stirrer . 7
4.3 Antennas . 7
4.4 Test equipment . 8
4.5 Device under test (DUT). 9
4.6 Linking devices . 9
5 Measurement procedure. 10
5.1 General. 10
5.2 Measurement of the DUT . 10
5.3 Measurement of the insertion loss of the cavity. 10
5.4 Control of the test set-up. 11
5.5 Revolution speed of the mode stirrer . 12
5.6 Test frequencies . 12
5.7 Voltage standing wave ratio (VSWR) . 12
6 Evaluation of the test results . 12
6.1 Screening attenuation . 12
6.2 Relationship between transfer impedance parameters and screening attenuation. 13
6.3 Electromagnetic field surrounding the DUT . 14
Annex A (informative) Design of the reverberation chamber . 15
Annex B (informative) Design of the mode stirrer . 16
Annex C (informative) Example of a calibrator. 18
Annex D (informative) Relationship between transfer impedance and
screening attenuation .20
Bibliography . 22

61726 © IEC:1999(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
CABLE ASSEMBLIES, CABLES, CONNECTORS
AND PASSIVE MICROWAVE COMPONENTS –
SCREENING ATTENUATION MEASUREMENT
BY THE REVERBERATION CHAMBER METHOD
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 61726 has been prepared by subcommittee 46A: Coaxial cables, of
IEC technical committee 46: Cables, wires, waveguides, r.f. connectors and accessories for
communication and signalling.
This second edition cancels and replaces the first edition, which was issued as a type 3
technical report in 1995. It constitutes a technical revision and now has the status of an
International Standard.
The text of this standard is based on the following documents:
FDIS Report on voting
46A/356/FDIS 46A/359/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, Part 3.
Annexes A, B, C and D are for information only.

– 4 – 61726 © IEC:1999(E)
The committee has decided that this publication remains valid until 2005. At this date, in
accordance with the committee's decision, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
61726 © IEC:1999(E) – 5 –
INTRODUCTION
The requirements of modern electronic equipment have indicated a demand for a method of
testing screening attenuation of microwave components over their whole frequency range.
Convenient test methods exist for low frequencies and components of regular shape and these
test methods are described in the relevant product specifications.
For higher frequencies and for components of irregular shape a new test method has become
necessary and such a test method is described in this International Standard.

– 6 – 61726 © IEC:1999(E)
CABLE ASSEMBLIES, CABLES, CONNECTORS
AND PASSIVE MICROWAVE COMPONENTS –
SCREENING ATTENUATION MEASUREMENT
BY THE REVERBERATION CHAMBER METHOD
1 Scope
This International Standard describes the measurement of screening attenuation by the
reverberation chamber test method, sometimes named mode stirred chamber, suitable for
virtually any type of microwave component and having no theoretical upper frequency limit. It is
only limited toward low frequencies due to the size of the test equipment, which is frequency
dependent and is only one of several methods of measuring screening attenuation.
For the purpose of this standard, examples of microwave components are waveguides, phase
shifters, diplexers/multiplexers, power dividers/combiners etc.
2 Basic description of the reverberation chamber method
The reverberation chamber method for measurement of the screening attenuation of
microwave components consists of exposing the device under test (DUT) to an almost
homogeneous and isotropic electromagnetic field and then measuring the signal level induced
into the device.
These conditions are achieved by the use of a shielded enclosure, which acts as an oversized
cavity (in terms of wavelength), with a high quality factor. Its boundary conditions are
continuously agitated by a rotating reflective surface (mode stirrer), mounted within the
chamber, which enables the field to approach homogeneous and isotropic conditions during
one revolution.
Electromagnetic power is fed to the chamber by means of an input or transmitting antenna.
The strength of the field inside the chamber is measured through a reference antenna. The
ratio of the injected power (input antenna) to the received power (reference antenna) is the
insertion loss of the cavity. The insertion loss is strongly frequency dependent and is also
dependent on the quality factor of the cavity.
It has been shown that, due to the isotropic field, any antenna placed inside the cavity behaves
1)
as if its gain was unity [1] , therefore no directional effect is to be expected. If the device
under test is electrically short, its screening attenuation will be directly related to usual transfer
parameters (Z and Z). If the device under test is not electrically short the screening
t f
attenuation may still be related to Z and Z in some simple cases (evenly distributed leakage,
t f
periodically distributed leakage) using summing functions derived from antenna network theory.
___________
1)
Figures in square brackets refer to the Bibliography.

61726 © IEC:1999(E) – 7 –
3 Measurement of the screening attenuation of the device under test (DUT)
The measurement of screening attenuation is based on the comparison of the electromagnetic
field power outside the DUT to the electromagnetic field power induced into the DUT. The
screening attenuation is then defined as:
 P 
DUT
 
a = −10 log (1)
s 10
 
P
REF
 
or:
 P 
DUT
a = −10 log   (2)
− Δ
s 10 ins
 
P
 INJ 
where
P is the power coupled to the device under test (W);
DUT
P is the power coupled to the reference antenna (W);
REF
P is the power injected into the chamber (W);
INJ
Δ is the insertion loss of the chamber in decibels (dB).
ins
4 Description of the test set-up
4.1 Reverberation chamber
The reverberation chamber is a shielded enclosure having any shape, provided that its smallest
dimension exceeds three wavelengths at the lowest test frequency. A perfect cubic shape
should be avoided for optimum performance at lower frequencies. It shall be made of
conductive materials (copper, aluminium or steel) and shall not contain lossy materials.
The upper frequency limit depends only on the screening attenuation, which shall exceed 60 dB
for the whole frequency range. However, this value is not critical if the spectrum analyzer and
the connecting devices of the test set-up are sufficiently screened and if the quality factor of
the cavity remains sufficiently high. The quality factor shall be checked to verify that during one
revolution of the mode stirrer the ratio between the maximum and the
...

IEC 61726
Edition 2.0 1999-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Cable assemblies, cables, connectors and passive microwave components –
Screening attenuation measurement by the reverberation chamber method

Câbles, cordons, connecteurs et composants hyperfréquence passifs – Mesure
de l’atténuation d’écran par la méthode de la chambre réverbérante

Copyright © 1999 IEC, Geneva, Switzerland

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by
any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either IEC or
IEC's member National Committee in the country of the requester.
If you have any questions about IEC copyright or have an enquiry about obtaining additional rights to this publication,
please contact the address below or your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de la CEI ou du Comité national de la CEI du pays du demandeur.
Si vous avez des questions sur le copyright de la CEI ou si vous désirez obtenir des droits supplémentaires sur cette
publication, utilisez les coordonnées ci-après ou contactez le Comité national de la CEI de votre pays de résidence.

IEC Central Office
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: [e-mail]
Web: www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.
ƒ Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
ƒ IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
ƒ Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
ƒ Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: [e-mail]
Tel.: [phone]
Fax: [phone]
A propos de la CEI
La Commission Electrotechnique Internationale (CEI) est la première organisation mondiale qui élabore et publie des
normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications CEI
Le contenu technique des publications de la CEI est constamment revu. Veuillez vous assurer que vous possédez
l’édition la plus récente, un corrigendum ou amendement peut avoir été publié.
ƒ Catalogue des publications de la CEI: www.iec.ch/searchpub/cur_fut-f.htm
Le Catalogue en-ligne de la CEI vous permet d’effectuer des recherches en utilisant différents critères (numéro de référence,
texte, comité d’études,…). Il donne aussi des informations sur les projets et les publications retirées ou remplacées.
ƒ Just Published CEI: www.iec.ch/online_news/justpub
Restez informé sur les nouvelles publications de la CEI. Just Published détaille deux fois par mois les nouvelles
publications parues. Disponible en-ligne et aussi par email.
ƒ Electropedia: www.electropedia.org
Le premier dictionnaire en ligne au monde de termes électroniques et électriques. Il contient plus de 20 000 termes et
définitions en anglais et en français, ainsi que les termes équivalents dans les langues additionnelles. Egalement appelé
Vocabulaire Electrotechnique International en ligne.
ƒ Service Clients: www.iec.ch/webstore/custserv/custserv_entry-f.htm
Si vous désirez nous donner des commentaires sur cette publication ou si vous avez des questions, visitez le FAQ du
Service clients ou contactez-nous:
Email: [e-mail]
Tél.: [phone]
Fax: [phone]
IEC 61726
Edition 2.0 1999-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Cable assemblies, cables, connectors and passive microwave components –
Screening attenuation measurement by the reverberation chamber method

Câbles, cordons, connecteurs et composants hyperfréquence passifs – Mesure
de l’atténuation d’écran par la méthode de la chambre réverbérante

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
S
CODE PRIX
ICS 33.120.10; 33.120.30 ISBN 2-8318-5737-6
– 2 – 61726 © CEI:1999
SOMMAIRE
Pages
AVANT-PROPOS .4
INTRODUCTION.8
Articles
1 Domaine d'application.10
2 Description de base de la méthode en chambre réverbérante.10
3 Mesure de l'atténuation d'écran d'un composant en essai (DUT) .12
4 Description du montage d'essai.12
4.1 Chambre réverbérante.12
4.2 Variateur de mode .12
4.3 Antennes.12
4.4 Equipement d'essai.14
4.5 Dispositif en essai .16
4.6 Dispositifs de liaison.16
5 Procédure de mesure .18
5.1 Généralités.18
5.2 Mesure du composant en essai.18
5.3 Mesure des pertes d'insertion de la cavité.18
5.4 Vérification du système d'essai .20
5.5 Vitesse de rotation du variateur de mode .22
5.6 Fréquence d'essais.22
5.7 Rapport d'ondes stationnaires (ROS) .22
6 Evaluation des résultats d'essai .22
6.1 Atténuation d'écran.22
6.2 Relation entre les paramètres d'impédance de transfert et l'atténuation d'écran.24
6.3 Champ électromagnétique dans l'environnement du composant en essai .26
Annexe A (informative) Description de la chambre réverbérante .28
Annexe B (informative) Description du variateur de mode .30
Annexe C (informative) Exemple de calibreur .34
Annexe D (informative) Relation entre l'impédance de transfert et l'atténuation d'écran.38
Bibliographie .42
Figure 1 – Exemple de dispositif d'essai .14
Figure B.1 – Schéma de construction du variateur de mode.32
Figure B.2 – Détails de la bride de passage pour piloter le variateur de mode à travers
la paroi de la chambre.32
Figure C.1 – Détails de construction de base.34

61726 © IEC:1999 – 3 –
CONTENTS
Page
FOREWORD.5
INTRODUCTION.9
Clause
1 Scope.11
2 Basic description of the reverberation chamber method.11
3 Measurement of the screening attenuation of the device under test (DUT).13
4 Description of the test set-up .13
4.1 Reverberation chamber.13
4.2 Mode stirrer.13
4.3 Antennas.13
4.4 Test equipment.15
4.5 Device under test (DUT) .17
4.6 Linking devices.17
5 Measurement procedure.19
5.1 General.19
5.2 Measurement of the DUT.19
5.3 Measurement of the insertion loss of the cavity .19
5.4 Control of the test set-up .21
5.5 Revolution speed of the mode stirrer.23
5.6 Test frequencies.23
5.7 Voltage standing wave ratio (VSWR).23
6 Evaluation of the test results .23
6.1 Screening attenuation .23
6.2 Relationship between transfer impedance parameters and screening attenuation .25
6.3 Electromagnetic field surrounding the DUT .27
Annex A (informative) Design of the reverberation chamber.29
Annex B (informative) Design of the mode stirrer.31
Annex C (informative) Example of a calibrator .35
Annex D (informative) Relationship between transfer impedance and screening attenuation .39
Bibliography .43
Figure 1 – Example of a test set-up .15
Figure B.1 – Construction diagram for mode-stirrer.33
Figure B.2 – Details of collet for mounting tuner shaft to drive motor through the
wall of the test chamber .33
Figure C.1 – Basic construction details.35

– 4 – 61726 © CEI:1999
COMMISSION ÉLECTROTECHNIQUE INTERNATIONALE
____________
CÂBLES, CORDONS, CONNECTEURS
ET COMPOSANTS HYPERFRÉQUENCE PASSIFS –
MESURE DE L'ATTÉNUATION D'ÉCRAN
PAR LA MÉTHODE DE LA CHAMBRE RÉVERBÉRANTE

AVANT-PROPOS
1) La CEI (Commission Électrotechnique Internationale) est une organisation mondiale de normalisation composée
de l'ensemble des comités électrotechniques nationaux (Comités nationaux de la CEI). La CEI a pour objet de
favoriser la coopération internationale pour toutes les questions de normalisation dans les domaines de
l'électricité et de l'électronique. A cet effet, la CEI, entre autres activités, publie des Normes internationales.
Leur élaboration est confiée à des comités d'études, aux travaux desquels tout Comité national intéressé par le
sujet traité peut participer. Les organisations internationales, gouvernementales et non gouvernementales, en
liaison avec la CEI, participent également aux travaux. La CEI collabore étroitement avec l'Organisation
Internationa
...