SIST EN 62431:2009

Reflectivity of electromagnetic wave absorbers in millimetre wave frequency - Measurement methods (IEC 62431:2008)

This International Standard specifies the measurement methods for the reflectivity of electromagnetic wave absorbers (EMA) for the normal incident, oblique incident and each
polarized wave in the millimetre-wave range. In addition, these methods are also equally effective for the reflectivity measurement of other materials:
– measurement frequency range: 30 GHz to 300 GHz;
– reflectivity: 0 dB to –50 dB;
– incident angle: 0° to 80°.
NOTE This standard is applicable not only to those EMA which are widely used as counter-measures against communication faults, radio interference etc. , but also to those used in an anechoic chamber in some cases. EMAs may be any kind of material, and may have any arbitrary shape, configuration, or layered structure as pointed out
below.
Material: Conductive material, dielectric material, magnetic material.
Shape: planar-, pyramidal-, wedge-type, or other specific shapes.
Layer structure: single layer, multi layers, or graded-index material.

Verfahren zur Messung des Reflexionsvermögens von Absorbern für elektromagnetische Wellen im Millimeterwellen-Frequenzbereich (IEC 62431:2008)

Réflectivité des absorbeurs d'ondes électromagnétiques dans la plage des fréquences millimétriques - Méthodes de mesure (CEI 62431:2008)

La CEI 62431:2008 spécifie les méthodes de mesure de la réflectivité des absorbeurs d'ondes électromagnétiques (EMA: Electromagnetic Wave Absorber) pour une onde incidente normale, une onde incidente oblique et toute onde polarisée dans la plage des ondes millimétriques. En outre, ces méthodes sont aussi valables pour la mesure de réflectivité d'autres matériaux:
- plage des fréquences de mesure: 30 GHz à 300 GHz;
- réflectivité: 0 dB à -50 dB;
- angle d'incidence: 0° à 80°. La norme CEI 62431 annule et remplace le IEC/PAS. La présente version bilingue correspond à la version anglaise monolingue publiée en 2008-07.

Merilne metode za odbojnost absorberjev milimetrskih elektromagnetnih valov (IEC 62431:2008)

General Information

• Status: Published
• Publication Date: 11-Dec-2008
• ICS: 19.080 - Electrical and electronic testing
• Technical Committee: iTEL - Communication cables
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 05-Dec-2008
• Due Date: 09-Feb-2009
• Completion Date: 12-Dec-2008
• Ref Project: EN 62431:2008 - Reflectivity of electromagnetic wave absorbers in millimetre wave frequency - Measurement methods

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 62431:2009
01-februar-2009
Merilne metode za odbojnost absorberjev milimetrskih elektromagnetnih valov
(IEC 62431:2008)
Reflectivity of electromagnetic wave absorbers in millimetre wave frequency -
Measurement methods (IEC 62431:2008)
Verfahren zur Messung des Reflexionsvermögens von Absorbern für elektromagnetische
Wellen im Millimeterwellen-Frequenzbereich (IEC 62431:2008)
Réflectivité des absorbeurs d'ondes électromagnétiques dans la plage des fréquences
millimétriques - Méthodes de mesure (CEI 62431:2008)
Ta slovenski standard je istoveten z: EN 62431:2008
ICS:
19.080 (OHNWULþQRLQHOHNWURQVNR Electrical and electronic
SUHVNXãDQMH testing
SIST EN 62431:2009 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 62431:2009SIST EN 62431:2009

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SIST EN 62431:2009SIST EN 62431:2009

EUROPEAN STANDARD
EN 62431

NORME EUROPÉENNE
December 2008
EUROPÄISCHE NORM

ICS 19.080; 17.020; 29.120.10


English version


Reflectivity of electromagnetic wave absorbers
in millimetre wave frequency -
Measurement methods
(IEC 62431:2008)


Réflectivité des absorbeurs d'ondes Verfahren zur Messung
électromagnétiques dans la plage des Reflexionsvermögens von Absorbern
des fréquences millimétriques - für elektromagnetische Wellen
Méthodes de mesure im Millimeterwellen-Frequenzbereich
(CEI 62431:2008) (IEC 62431:2008)




This European Standard was approved by CENELEC on 2008-11-01. 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, Bulgaria, Cyprus, the
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the 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


© 2008 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62431:2008 E

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SIST EN 62431:2009SIST EN 62431:2009
EN 62431:2008 – 2 –
Foreword
The text of document 46F/65/CDV, future edition 1 of IEC 62431, prepared by SC 46F, R.F. and
microwave passive components, of IEC TC 46, Cables, wires, waveguides, R.F. connectors, R.F. and
microwave passive components and accessories, was submitted to the IEC-CENELEC Parallel Unique
Acceptance Procedure and was approved by CENELEC as EN 62431 on 2008-11-01.
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) 2009-08-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2011-11-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 62431:2008 was approved by CENELEC as a European
Standard without any modification.
__________

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SIST EN 62431:2009SIST EN 62431:2009
– 3 – EN 62431:2008

Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications

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.

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) 2)
ISO/IEC 17025 - General requirements for the competence EN ISO/IEC 17025 2005
of testing and calibration laboratories




1)
Undated reference.
2)
Valid edition at date of issue.

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SIST EN 62431:2009SIST EN 62431:2009

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SIST EN 62431:2009SIST EN 62431:2009



IEC 62431
Edition 1.0 2008-07
INTERNATIONAL
STANDARD


Reflectivity of electromagnetic wave absorbers in millimetre wave frequency –
Measurement methods


INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XA
ICS 19.080; 17.120; 29.120.10 ISBN 2-8318-9895-1
® Registered trademark of the International Electrotechnical Commission

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SIST EN 62431:2009SIST EN 62431:2009
– 2 – 62431 © IEC:2008(E)
CONTENTS
FOREWORD.5
1 Scope.7
2 Normative references .7
3 Terms, definitions and acronyms .7
3.1 Terms and definitions .7
3.2 Acronyms and symbols.10
4 Specimen .12
4.1 Specimen specification.12
4.2 Reference metal plate .12
4.2.1 Material and thickness.12
4.2.2 Surface roughness .12
4.2.3 Flatness .12
4.2.4 Size and shape.12
4.3 Reference specimen for calibration .12
5 Specimen holder .13
6 Measurement equipment .13
6.1 Type of network analyzer .13
6.2 Antenna .13
6.2.1 Horn antenna.13
6.2.2 Lens antenna.13
6.3 Amplifier.13
6.4 Cable .14
7 Measurement condition .14
7.1 Temperature and environment.14
7.2 Warming up of measurement equipment.14
7.3 Electromagnetic environment .14
8 Calibration of measurement system and measurement conditions .14
8.1 Calibration of measurement system.14
8.2 Measurement conditions.14
8.2.1 Dynamic range .14
8.2.2 Setting up of the network analyzer for keeping adequate dynamic
range.14
9 Horn antenna method .15
9.1 Measurement system .15
9.1.1 Configuration of the measurement system .15
9.1.2 Horn antenna.16
9.1.3 Specimen holder.16
9.1.4 Mounting of the specimen.18
9.1.5 Antenna stand .18
9.2 Measurement conditions.18
9.2.1 Measurement environment .18
9.2.2 Measuring distance .18
9.2.3 Size of specimen .18
9.3 Measurement procedures .19
10 Dielectric lens antenna method – focused beam method .20
10.1 Outline .20

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SIST EN 62431:2009SIST EN 62431:2009
62431 © IEC:2008(E) – 3 –
10.2 Measurement system .20
10.2.1 Transmitting and receiving antennas .20
10.2.2 Focused beam horn antenna .21
10.2.3 Specimen size .22
10.2.4 Reference metal plate size .22
10.2.5 Specimen holder.22
10.2.6 Method of fixing the specimen and the reference metal plate.23
10.3 Measurement procedures .23
11 Dielectric lens antenna method – parallel beam method .25
11.1 Principle.25
11.1.1 Outline .25
11.1.2 Parallel EM wave beam formed using a EM wave lens.25
11.2 Measurement system .26
11.2.1 Composition of measurement system .26
11.2.2 Dielectric lens antenna .29
11.3 Specimen .29
11.3.1 General .29
11.3.2 Reference metal plate .29
11.3.3 Size of specimen .30
11.4 Measurement procedures .30
11.4.1 Normal incidence.30
11.4.2 Oblique Incidence.30
12 Test report.31
Annex A (informative) Reflection and scattering from metal plate – Horn antenna
method .33
Annex B (informative) Reflectivity of reference specimens using horn antenna method.38
Annex C (informative) Specifications of commercially available antennas .39
Annex D (normative) Calibration using VNA.42
Annex E (informative) Dynamic range and measurement errors .51
Annex F (informative) Enlargement of dynamic range – Calibration by isolation .53
Annex G (informative) Relative permittivity of styrofoam and foamed polyethylene
based on foam ratio .54
Annex H (informative) Calculation of Fraunhofer region – Horn antenna method.55

Figure 1 – Definition of reflectivity.10
Figure 2 – Configuration of the measurement system normal incidence (S ).15
11
Figure 3 – Configuration of the measurement system oblique incidence (S ) .16
21
Figure 4 – Mounting method of specimen.17
Figure 5 – The mechanism of adjusting azimuth and elevation.17
Figure 6 – Measurement system for normal incidence (side view) .20
Figure 7 – Measurement system for oblique incidence (top view).21
Figure 8 – Structure of a dielectric lens antenna .22
Figure 9 – Structure of specimen holder.23
Figure 10 – EM wave propagation using a horn antenna and a dielectric lens .26
Figure 11 – Block diagram of the measurement system .27
Figure 12 – A measurement system for normal incidence .28

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SIST EN 62431:2009SIST EN 62431:2009
– 4 – 62431 © IEC:2008(E)
Figure 13 – Measurement system for oblique incidence .28
Figure 14 – Position of a shielding plate .29
Figure 15 – Items to be mentioned in a test report .32
Figure A.1 – Reflection from the reference metal plate versus measurement distance
between the antenna and the metal plate.33
Figure A.2 – Reflectivity of reference metal plate versus size.34
Figure A.3 – Reflectivity of reference metal plate at 40 GHz .35
Figure A.4 – Reflectivity of reference metal plate with cross section of 200 mm ×
200 mm at 40 GHz.35
Figure A.5 – Analysis of reflection from a metal plate.37
Figure B.1 – Reflectivity of a 200 mm × 200 mm silica-glass plate in millimetre wave
frequency.38
Figure C.1 – Representative specifications of a horn antenna.39
Figure C.2 – Structure of cylindrical horn antenna with dielectric lens in Table C.2, A
40
used at 50 GHz - 75 GHz.
Figure C.3 – A structure of dielectric lens and horn antenna in Table C.2, D.41
Figure D.1 – Measurement configuration for the case of normal incidence with a
directional coupler connected directly to the horn antenna .42
Figure D.2 – Configuration for response calibration using a reference metal plate in the
case of normal incidence .43
Figure D.3 – Configuration for response calibration using a reference metal plate in the
case of oblique incidence.44
Figure D.4 – Configuration for response and isolation calibration in the case of normal
incidence .45
Figure D.5a – Response calibration    Figure D.5b – Isolation calibration.45
Figure D.5 – Configuration for response and isolation calibration in the case of oblique
incidence .45
Figure D.6 – Configuration for S 1-port full calibration in the case of normal
11
47
incidence .
Figure D.7 – Precision antenna positioner configuration.48
Figure D.8 – TRL calibration procedure.49
Figure D.9 – Measurement and TRL calibration of transmission line .50
Figure E.1 – An example of receiving level of a reference metal plate and that without
a specimen .51
Figure E.2 – Dynamic range and measurement error of reflectivity.52
Figure F.1 – A method to remove spurious waves .53
Figure H.1 – Fraunhofer region and antenna gain .55

Table 1 – Acronyms .11
Table 2 – Symbols .11
Table C.1 – Antenna gain 24 dB (example A).39
Table C.2 – Some specifications of antennas with dielectric lenses .40
Table G.1 – Relative permittivity and foam ratio of styrofoam.54
Table G.2 – Relative permittivity and foam ratio of foamed polyethylene.54

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SIST EN 62431:2009SIST EN 62431:2009
62431 © IEC:2008(E) – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

REFLECTIVITY OF ELECTROMAGNETIC
WAVE ABSORBERS IN MILLIMETRE WAVE FREQUENCY –
MEASUREMENT METHODS


FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of 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, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”. 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. 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 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) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) EC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damages
or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62431 has been prepared by subcommittee SC46F: RF and
microwave passive components, of IEC technical committee 46: Cables, wires, waveguides,
R.F. connectors, R.F. and microwave passive components and accessories.
IEC 62431 replaces and cancels IEC/PAS 62431 with corrections of obvious errors as noted
in 46F/29A/RVN.
The text of this standard is based on the following documents:
CDV Report on voting
46F/65/CDV 46F/72/RVC

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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SIST EN 62431:2009SIST EN 62431:2009
– 6 – 62431 © IEC:2008(E)
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under “http://webstore.iec.ch” in the
data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

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SIST EN 62431:2009SIST EN 62431:2009
62431 © IEC:2008(E) – 7 –
REFLECTIVITY OF ELECTROMAGNETIC
WAVE ABSORBERS IN MILLIMETRE WAVE FREQUENCY –
MEASUREMENT METHODS



1 Scope
This International Standard specifies the measurement methods for the reflectivity of
electromagnetic wave absorbers (EMA) for the normal incident, oblique incident and each
polarized wave in the millimetre-wave range. In addition, these methods are also equally
effective for the reflectivity measurement of other materials:
– measurement frequency range: 30 GHz to 300 GHz;
– reflectivity: 0 dB to –50 dB;
– incident angle: 0° to 80°.
NOTE This standard is applicable not only to those EMA which are widely used as counter-measures against
communication faults, radio interference etc. , but also to those used in an anechoic chamber in some cases. EMAs
may be any kind of material, and may have any arbitrary shape, configuration, or layered structure as pointed out
below.
Material: Conductive material, dielectric material, magnetic material.
Shape: planar-, pyramidal-, wedge-type, or other specific shapes.
Layer structure: single layer, multi layers, or graded-index material.
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.
ISO/IEC 17025, General requirements for the competence of testing and calibration
laboratories
3 Terms, definitions and acronyms
For the purposes of this document, the following terms and definitions apply.
3.1 Terms and definitions
3.1.1
ambient level
the value of radiation power or noise which exists when no measurement is being carried out
at the experiment site
3.1.2
associated equipment
an apparatus or product connected for convenience or operation of the equipment
3.1.3
beam diameter
the diameter where the electric field strength decreases by 3 dB from the centre of the
focused beam

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SIST EN 62431:2009SIST EN 62431:2009
– 8 – 62431 © IEC:2008(E)
3.1.4
beam waist
the portion at which the diameter of the focused beam becomes minimum when the
electromagnetic waves radiated from a transmit antenna are converged using a dielectric lens
3.1.5
beam waist diameter
beam diameter at the beam waist
3.1.6
bistatic measurement
measurement where the incident and reflection angle are equal
3.1.7
dielectric lens
electromagnetic wave lens that is composed of dielectric material
Usually, it is used by mounting in front of a pyramidal or conical horn.
3.1.8
directional gain
ratio of the radiated power density in a particular direction to the average power density that
would be radiated in all directions
3.1.9
dynamic range
difference in decibels between the receiving level from the reference metal plate and the
receiving level measured when the metal plate is removed
3.1.10
electromagnetic wave absorber
material ingredient which absorbs the electromagnetic wave energy and dissipates it
thermally
3.1.11
focal distance
distance between the centre of the dielectric lens and the focal point
3.1.12
focal point
centre of the beam waist when the electromagnetic waves are converged using a dielectric
lens
3.1.13
focused beam
focused electromagnetic wave converged by the dielectric lens mounted in front of the horn
antenna
The focused beam diameter is a few times the wavelength or more at the beam waist, which
depends on the focal distance of the lens.
3.1.14
fraunhofer region
region where the angular radiation pattern of an aperture antenna is nearly independent of the
distance

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SIST EN 62431:2009SIST EN 62431:2009
62431 © IEC:2008(E) – 9 –
3.1.15
free-space method
measurement method that employs a single or pair of horn antennas where the specimen and
the antennas are put in free space
3.1.16
fresnel region
region where the
...