SIST EN 61000-4-20:2005
(Main)Electromagnetic compatibility (EMC) -- Part 4-20: Testing and measurement techniques - Emission and immunity testing in transverse electromagnetic (TEM) waveguides
Electromagnetic compatibility (EMC) -- Part 4-20: Testing and measurement techniques - Emission and immunity testing in transverse electromagnetic (TEM) waveguides
Relates to emission and immunity test methods for electrical and electronic equipment using various types of transverse electromagnetic (TEM) waveguides. This includes open (for example, striplines and EMP simulators) and closed (for example, TEM cells) structures, which can be further classified as one-, two-, or multi-port TEM waveguides. The frequency range depends on the specific testing requirements and the specific TEM waveguide type. The object of this standard is to describe · TEM waveguide characteristics, including typical frequency ranges and EUT-size limitations (EUT = equipment under test); · TEM waveguide validation methods for EMC measurements; · the EUT (i.e. EUT cabinet and cabling) definition; · test set-ups, procedures, and requirements for radiated emission testing in TEM waveguides and · test set-ups, procedures, and requirements for radiated immunity testing in TEM waveguides.
Elektromagnetische Verträglichkeit (EMV) -- Teil 4-20: Prüf- und Messverfahren - Messung der Störaussendung und Störfestigkeit in transversal-elektromagnetischen (TEM-) Wellenleitern
Compatibilité électromagnétique (CEM) -- Partie 4-20: Techniques d'essai et de mesure - Essais d'émission et d'immunité dans les guides d'onde TEM
Concerne les méthodes d'essai d'émission et d'immunité pour les équipements électriques et électroniques utilisant différents types de guides d'onde transverse électromagnétique (TEM). Ces types comprennent des structures ouvertes (par exemple, des lignes ouvertes et des simulateurs d'impulsion électromagnétique), et des structures fermées (par exemple des cellules TEM), qui peuvent être elles-mêmes classées en guides d'onde TEM à un accès, à deux accès, ou à accès multiples. La gamme de fréquences dépend des exigences d'essai spécifiques et du type spécifique de guide d'onde TEM. L'objet de cette norme est de décrire · les caractéristiques des guides d'onde TEM, y compris les gammes de fréquences types et les limites de tailles des appareils en essai; · les méthodes de validation des guides d'onde TEM pour les mesures de CEM; · la définition de l'appareil en essai (c'est-à-dire l'armoire et le câblage de l'appareil en essai); · les montages d'essai, les procédures et les exigences pour les essais d'émissions rayonnées dans les lignes TEM, et · les montages d'essai, les procédures et les exigences pour les essais d'immunité rayonnée dans les guides d'onde TEM.
Elektromagnetna združljivost (EMC) – 4-20. del: Preskusne in merilne tehnike – Preskušanje oddajanja in odpornosti pri prečnih elektromagnetnih (TEM) valovih (IEC 61000-4-20:2003)
General Information
Relations
Standards Content (Sample)
SLOVENSKI SIST EN 61000-4-20:2005
STANDARD
julij 2005
Elektromagnetna združljivost (EMC) – 4-20. del: Preskusne in merilne tehnike –
Preskušanje oddajanja in odpornosti pri prečnih elektromagnetnih (TEM)
valovih (IEC 61000-4-20:2003)
Electromagnetic compatibility (EMC) – Part 4-20: Testing and measurement
techniques – Emission and immunity testing in transverse electromagnetic (TEM)
waveguides (IEC 61000-4-20:2003)
ICS 33.100.10; 33.100.20 Referenčna številka
SIST EN 61000-4-20:2005(en)
© Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno
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EUROPEAN STANDARD EN 61000-4-20
NORME EUROPÉENNE
EUROPÄISCHE NORM April 2003
ICS 33.100.10; 33.100.20
English version
Electromagnetic compatibility (EMC)
Part 4-20: Testing and measurement techniques –
Emission and immunity testing
in transverse electromagnetic (TEM) waveguides
(IEC 61000-4-20:2003)
Compatibilité électromagnétique (CEM) Elektromagnetische Verträglichkeit (EMV)
Partie 4-20: Techniques d'essai Teil 4-20: Prüf- und Messverfahren -
et de mesure – Messung der Störaussendung
Essais d'émission et d'immunité und Störfestigkeit in transversal-
dans les guides d'onde TEM elektromagnetischen (TEM-) Wellenleitern
(CEI 61000-4-20:2003) (IEC 61000-4-20:2003)
This European Standard was approved by CENELEC on 2003-04-01. CENELEC members are bound to
comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on
application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CENELEC member into its own language and
notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta,
Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61000-4-20:2003 E
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EN 61000-4-20:2003 - 2 -
Foreword
The text of document CIS/A/419/FDIS, future edition 1 of IEC 61000-4-20, prepared by CISPR SC A,
Radio-interference measurements and statistical methods, in cooperation with SC 77B, High
frequency phenomena, of IEC TC 77, Electromagnetic compatibility, was submitted to the
IEC-CENELEC parallel vote and was approved by CENELEC as EN 61000-4-20 on 2003-04-01.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2004-01-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2006-04-01
Annexes designated "normative" are part of the body of the standard.
Annexes designated "informative" are given for information only.
In this standard, annexes A, B, C and ZA are normative and annexes D and E are informative.
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61000-4-20:2003 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards
indicated:
CISPR 14 NOTE Harmonized in EN 55014 series (not modified).
CISPR 20 NOTE Harmonized as EN 55020:2002 (not modified).
IEC 61000-2-9 NOTE Harmonized as EN 61000-2-9:1996 (not modified).
__________
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- 3 - EN 61000-4-20:2003
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of any
of these publications apply to this European Standard only when incorporated in it by amendment or
revision. For undated references the latest edition of the publication referred to applies (including
amendments).
NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
Publication Year Title EN/HD Year
1)
-
IEC 60050-161 International Electrotechnical - -
Vocabulary (IEV)
Chapter 161: Electromagnetic
compatibility
2)
- 1)
IEC 60068-1 Environmental testing EN 60068-1 1994
Part 1: General and guidance
- 1)
IEC 61000-2-11 Electromagnetic compatibility (EMC) - -
Part 2-11: Environment - Classification
of HEMP environments
- 1) 2)
IEC 61000-4-3 Part 4-3: Testing and measurement EN 61000-4-3 2002
techniques - Radiated, radio-
frequency, electromagnetic field
immunity test
- 1) 2)
IEC 61000-4-23 Part 4-23: Testing and measurement EN 61000-4-23 2000
techniques - Test methods for
protective devices for HEMP and other
radiated disturbances
- 1)
IEC/TR 61000-4-32 Electromagnetic compatibility (EMC) - - -
Part 4-32: Testing and measurement
techniques - HEMP simulator
compendium
- 1)
IEC/TR 61000-5-3 Part 5: Installation and mitigation - -
guidelines -- Section 3: HEMP
protection concepts
1)
Undated reference.
2)
Valid edition at date of issue.
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EN 61000-4-20:2003 - 4 -
Publication Year Title EN/HD Year
- 1)
CISPR 16-1 Specification for radio disturbance and - -
immunity measuring apparatus and
methods
Part 1: Radio disturbance and
immunity measuring apparatus
- 1)
CISPR 16-2 Part 2: Methods of measurement of - -
disturbances and immunity
- 1) 2)
CISPR 22 (mod) Information technology equipment - EN 55022 1998
Radio disturbance characteristics -
Limits and methods of measurement
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INTERNATIONAL IEC
STANDARD
61000-4-20
First edition
2003-01
BASIC EMC PUBLICATION
Electromagnetic compatibility (EMC) –
Part 4-20:
Testing and measurement techniques –
Emission and immunity testing in transverse
electromagnetic (TEM) waveguides
IEC 2003 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, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
PRICE CODE
XB
Commission Electrotechnique Internationale
International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue
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61000-4-20 IEC:2003 – 3 –
CONTENTS
FOREWORD . 7
INTRODUCTION .11
1 Scope and object .13
2 Normative references.13
3 Definitions and abbreviations.15
3.1 Definitions .15
3.2 Abbreviations.21
4 General .21
5 TEM waveguide requirements.23
5.1 General requirements for the use of TEM waveguides .23
5.2 Special requirements for certain types of TEM waveguides.27
5.3 Measurement uncertainty considerations .29
6 Overview of EUT Types .29
6.1 Small EUT .29
6.2 Large EUT .29
Annex A (normative) Emission testing in TEM waveguides .31
Annex B (normative) Immunity testing in TEM waveguides .75
Annex C (normative) HEMP transient testing in TEM waveguides.91
Annex D (informative) TEM waveguide characterization .107
Annex E (informative) Standards including TEM waveguides.121
Bibliography.125
Figure A.1 – Routing the exit cable to the corner at the ortho-angle and the lower edge
of the test volume.55
Figure A.2 – Basic ortho-axis positioner or manipulator.57
Figure A.3 – Three orthogonal axis-rotation positions for emission measurements .59
Figure A.4 – Canonical 12-face/axis orientations for a typical EUT.61
Figure A.5 – Open-area test site geometry .63
Figure A.6 – Two-port TEM cell (symmetric septum) .65
Figure A.7 – One-port TEM cell (asymmetric septum).67
Figure A.8 – Stripline (two plates) .71
Figure A.9 – Stripline (four plates, balanced feeding) .73
Figure B.1 – Example of test set-up for single-polarization TEM waveguides.87
Figure B.2 – Uniform area calibration points in TEM waveguide .89
Figure C.1 – Frequency domain spectral magnitude between 100 kHz and 300 MHz.105
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61000-4-20 IEC:2003 – 5 –
Figure D.1 – Simplest waveguide (no TEM wave!).119
Figure D.2 – Waveguides for TEM propagation .119
Figure D.3 – Polarization vector .119
Figure D.4 – Transmission line model for TEM propagation.119
Figure D.5 – One- and two-port TEM waveguides.119
Table B.1 – Uniform area calibration points.79
Table B.2 – Test levels.81
Table C.1 – Radiated immunity test levels defined in the present standard.105
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61000-4-20 IEC:2003 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTROMAGNETIC COMPATIBILITY (EMC) –
Part 4-20: Testing and measurement techniques –
Emission and immunity testing in
transverse electromagnetic (TEM) waveguides
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 61000-4-20 has been prepared by CISPR subcommittee A: Radio
interference measurements and statistical methods, in cooperation with subcommittee 77B:
High-frequency phenomena, of IEC technical committee 77: Electromagnetic compatibility.
This standard forms Part 4-20 of IEC 61000. It has the status of a basic EMC publication in
accordance with IEC Guide 107.
The text of this standard is based on the following documents:
Committee draft Report on voting
CIS/A/419/FDIS CIS/A/435/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 2.
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61000-4-20 IEC:2003 – 9 –
The committee has decided that the contents of this publication will remain unchanged until
2004. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
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61000-4-20 IEC:2003 – 11 –
INTRODUCTION
IEC 61000 is published in separate parts according to the following structure:
Part 1: General
General considerations (introduction, fundamental principles)
Definitions, terminology
Part 2: Environment
Description of the environment
Classification of the environment
Compatibility levels
Part 3: Limits
Emission limits
Immunity limits (in so far as they do not fall under the responsibility of the product
committees)
Part 4: Testing and measurement techniques
Measurement techniques
Testing techniques
Part 5: Installation and mitigation guidelines
Installation guidelines
Mitigation methods and devices
Part 6: Generic Standards
Part 9: Miscellaneous
Each part is further subdivided into several parts, published either as International Standards,
Technical Specifications or Technical Reports, some of which have already been published as
sections. Others will be published with the part number followed by a dash and a second
number identifying the subdivision (example: 61000-6-1).
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61000-4-20 IEC:2003 – 13 –
ELECTROMAGNETIC COMPATIBILITY (EMC) –
Part 4-20: Testing and measurement techniques –
Emission and immunity testing in
transverse electromagnetic (TEM) waveguides
1 Scope and object
This part of IEC 61000 relates to emission and immunity test methods for electrical and
electronic equipment using various types of transverse electromagnetic (TEM) waveguides.
This includes open (for example, striplines and EMP simulators) and closed (for example,
TEM cells) structures, which can be further classified as one-, two-, or multi-port TEM
waveguides. The frequency range depends on the specific testing requirements and the
specific TEM waveguide type.
The object of this standard is to describe
• TEM waveguide characteristics, including typical frequency ranges and EUT-size
limitations;
• TEM waveguide validation methods for EMC measurements;
• the EUT (i.e. EUT cabinet and cabling) definition;
• test set-ups, procedures, and requirements for radiated emission testing in TEM
waveguides and
• test set-ups, procedures, and requirements for radiated immunity testing in TEM
waveguides.
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(161), International Electrotechnical Vocabulary (IEV) – Chapter 161: Electro-
magnetic compatibility
IEC 60068-1, Environmental testing – Part 1: General and guidance.
IEC 61000-2-11, Electromagnetic compatibility (EMC) – Part 2-11: Environment – Classi-
fication of HEMP environments. Basic EMC publication
IEC 61000-4-3, Electromagnetic compatibility (EMC) – Part 4-3: Testing and measurement
techniques – Radiated, radio-frequency, electromagnetic field immunity test. Basic EMC
publication
IEC 61000-4-23, Electromagnetic compatibility (EMC) – Part 4-23: Testing and measurement
techniques – Test methods for protective devices for HEMP and other radiated disturbances.
Basic EMC publication
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61000-4-20 IEC:2003 – 15 –
IEC/TR 61000-4-32, Electromagnetic compatibility (EMC) – Part 4-32: Testing and measure-
ment techniques – HEMP simulator compendium
IEC/TR 61000-5-3, Electromagnetic compatibility (EMC) – Part 5-3: Installation and mitigation
guidelines – HEMP protection concepts. Basic EMC publication
CISPR 16-1, Specification for radio disturbance and immunity measuring apparatus and
methods – Part 1: Radio disturbance and immunity measuring apparatus
CISPR 16-2, Specification for radio disturbance and immunity measuring apparatus and
methods – Part 2: Methods of measurement of disturbances and immunity
CISPR 22, Information technology equipment – Radio disturbance characteristics – Limits and
methods of measurement
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this part of IEC 61000, the definitions given in IEC 60050(161) (IEV), as
well as the following, apply.
3.1.1
transverse electromagnetic (TEM) mode
waveguide mode in which the components of the electric and magnetic fields in the
propagation direction are much less than the primary field components across any transverse
cross-section
3.1.2
TEM waveguide
open or closed transmission line system, in which a wave is propagating in the transverse
electromagnetic mode to produce a specified field for testing purposes
3.1.3
TEM cell
enclosed TEM waveguide, often a rectangular coaxial line, in which a wave is propagated in
the transverse electromagnetic mode to produce a specific field for testing purposes. The
outer conductor completely encloses the inner conductor
3.1.4
two-port TEM waveguide
TEM waveguide with input/output measurement ports at both ends
3.1.5
one-port TEM waveguide
TEM waveguide with a single input/output measurement port. Such TEM waveguides typically
feature a broadband line termination at the non-measurement-port end
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61000-4-20 IEC:2003 – 17 –
3.1.6
stripline
terminated transmission line consisting of two or more parallel plates between which a wave
is propagated in the transverse electromagnetic mode to produce a specific field for testing
purposes. Usually the sides are open for EUT access and monitoring
3.1.7
inner conductor or septum
inner conductor of a coaxial transmission line system, often flat in the case of a rectangular
cross-section. The inner conductor may be positioned symmetrically or asymmetrically with
respect to the outer conductor
3.1.8
outer conductor or housing
outer conductor of a coaxial transmission line system, often having a rectangular cross-
section
3.1.9
characteristic impedance
for any constant phase wave-front, the magnitude of the ratio of the voltage between the inner
conductor and the outer conductor to the current on either conductor. The characteristic
impedance is independent of the voltage/current magnitudes and depends only on the cross-
sectional geometry of the transmission line. TEM waveguides are typically designed to have a
50 Ω characteristic impedance. TEM waveguides with a 100 Ω characteristic impedance are
often used for transient testing
3.1.10
anechoic material
material that exhibits the property of absorbing, or otherwise reducing, the level of
electromagnetic energy reflected from that material
3.1.11
broadband line termination
termination which combines a low-frequency discrete-component load, to match the
characteristic impedance of the TEM waveguides (typically 50 Ω), and a high-frequency
anechoic-material volume
3.1.12
correlation algorithm
mathematical routine for converting TEM waveguide voltage measurements to open-area test
sites (OATS), semi-anechoic chamber (SAC), or free space field strength levels
3.1.13
EUT type
grouping of products with sufficient similarity in electromagnetic characteristics to allow
testing with the same test installation and the same test protocol
3.1.14
exit cable
cable that connects the EUT to equipment external to the TEM waveguide or exiting the
usable test volume defined in 5.1.2.
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61000-4-20 IEC:2003 – 19 –
3.1.15
interconnecting cable
cable that connects subcomponents of the EUT within the test volume but does not exit the
test volume
3.1.16
test set-up support
non-reflecting, non-conducting, low-permittivity support and positioning reference that allows
for precise rotations of the EUT as required by a correlation algorithm or test protocol
1
NOTE 1 A typical material is foamed polystyrene. Wooden supports are not recommended (see [7] ).
3.1.17
ortho-angle
angle that the diagonal of a cube makes to each side face at the trihedral corners of the cube.
Assuming that the cube is aligned with the TEM waveguide Cartesian coordinate system, the
azimuth and elevation angles of the projection of the cube diagonal are 45°, and the angles to
the face edges are 54,7° (see Figure A.2a)
NOTE 2 When associated with the EUT, this angle is usually referred to as the ortho-axis.
3.1.18
primary (field) component
electric field component aligned with the intended test polarization
NOTE 3 For example, in conventional two-port TEM cells, the septum is parallel to the horizontal floor, and the
primary mode electric field vector is vertical at the transverse centre of the TEM cell.
3.1.19
secondary (field) component
in a Cartesian coordinate system, either of the two electric field components orthogonal to the
primary field component and orthogonal to each other
3.1.20
resultant field (amplitude)
root-sum-squared values in V/m of the primary and the two secondary field components
3.1.21
manipulator
any type of manual or automatic non-metallic fixtures similar to a turntable, and capable of
supporting an affixed EUT throughout numerous positions as required by a correlation
algorithm or test protocol. The material has to meet the requirements defined for the test set-
up support (see 3.1.16). For example, see Figure A.2
3.1.22
hyper-rotated TEM waveguide
TEM waveguide that has been reorientated such that its ortho-axis is normal to the Earth’s
surface (see [6])
———————
1
Figures in square brackets refer to the bibliography.
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61000-4-20 IEC:2003 – 21 –
3.1.23
gravity-dependent / -independent
the gravitation force of the earth has a fixed direction. The EUT can be rotated around all
three axes. Due to different rotation positions the EUT is affected by the gravitation force in
different directions. The EUT is gravity-independent if it is working properly in all positions,
which means working properly regardless of the direction of the gravity vector relative to the
EUT. The EUT is gravity-dependent if it does not work properly in one or more test positions
3.2 Abbreviations
BALUN Balanced-to-unbalanced transformer
DFT Discrete Fourier Transform
EUT Equipment under test
FFT Fast Fourier Transform
GTEM Gigahertz transverse electromagnetic mode
HEMP High-altitude electromagnetic pulse
OATS Open-area test site
PoE Points of entry
RF Radiofrequency
SAC Semi-anechoic chamber
SPD Surge protective device
TDR Time-domain reflectometer
TE Transverse electric (mode), (H-mode)
TEM Transverse electromagnetic mode
TM Transverse magnetic (mode), (E-mode)
VSWR Voltage-standing-wave-ratio
4 General
This standard describes basic characteristics and limitations of TEM waveguides, namely test
volume, field uniformity, purity of the TEM mode, and frequency ranges. An introduction and
some fundamental characteristics of TEM waveguides are given in Annex D.
Radiated emission measurements in a TEM waveguide are usually correlated with the open-
area test site (OATS) and semi-anechoic chamber (SAC) methods, which provide valid and
repeatable measurement results of disturbance field strength from equipment. In this case so-
called correlation algorithms are used to convert TEM waveguide measurement results to
OATS-equivalent data, as described in Annex A. Product committees should demonstrate that
good correlation exists between measurement results using typical product types.
TEM waveguides can also be used as field generators for testing the immunity of equipment
to electromagnetic fields. Details are given in Annex B. Immunity testing in TEM waveguides
is cited in several other standards listed in Annex E.
TEM waveguide measurements are not restricted to radiated measurements on fully
assembled equipment; they may also be applied to the testing of components, integrated
circuits, and the shielding effectiveness of gasket materials and cables.
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61000-4-20 IEC:2003 – 23 –
5 TEM waveguide requirements
TEM waveguides can be used for emission and immunity measurements when certain
requirements are met. For the validation of a TEM waveguide the following methods shall be
applied.
NOTE This clause focuses on general validation aspects such as the dominant TEM mode and field homogeneity.
Specific validation requirements for emission, immunity, and transient testing are given in the annexes.
5.1 General requirements for the use of TEM waveguides
5.1.1 TEM mode verification
TEM waveguides may exhibit resonances above a certain cut-off frequency determined by the
cross-sectional dimensions and/or the waveguide length. For practical use, the field in a TEM
waveguide is considered to propagate in a TEM mode when the following requirements are
met. Generally, a TEM waveguide manufacturer has to verify and document the TEM mode
behaviour over the desired frequency range and include verification data with the system
documentation.
NOTE 1 The TEM mode behaviour must be confirmed at regular intervals (see B.2.2).
Using an immunity-type uniform-area calibration procedure (according to B.2.2) the
magnitudes of the secondary (unintended) electric field components shall be at least 6 dB
less than the primary component of the electric field, over at least 75 % of the measured
points in a defined cross-section of the TEM waveguide (perpendicular to the propagation
direction). For this 75 % of measurement points, a primary electric field component tolerance
−0 −0
greater than dB up to dB , or a secondary electric field component level up to
+6 +10
–2 dB of the primary field component, is allowed for a maximum of 3 % of the test frequencies
(at least one frequency), provided that the actual tolerance and frequencies are stated in the
test reports
...
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