IEC 62153-4-15:2015

Metallic communication cable test methods - Part 4-15: Electromagnetic compatibility (EMC) - Test method for measuring transfer impedance and screening attenuation - or coupling attenuation with triaxial cell

IEC 62153-4-15:2015(E) specifies the procedures for measuring with triaxial cell the transfer impedance, screening attenuation or the coupling attenuation of connectors, cable assemblies and components, e.g. accessories for analogue and digital transmission systems and equipment for communication networks and cabling (in accordance with the scope of IEC technical committee 46). Measurements can be achieved by applying the device under test direct to the triaxial cell or with the tube in tube method in accordance with IEC 62153-4-7.

General Information

• Status: Published
• Publication Date: 03-Dec-2015
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 33.100.10 - Emission
• ICS: 33.120.10 - Coaxial cables. Waveguides
• Technical Committee: TC 46 - Cables, wires, waveguides, RF connectors, RF and microwave passive components and accessories
• Drafting Committee: WG 5 - TC 46/WG 5
• Current Stage: DELPUB - Deleted Publication
• Start Date: 03-Aug-2021
• Completion Date: 28-Jun-2019

Relations

• Revised: IEC 62153-4-15:2021 - Metallic cables and other passive components test methods - Part 4-15: Electromagnetic compatibility (EMC) - Test method for measuring transfer impedance and screening attenuation - or coupling attenuation with triaxial cell
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 62153-4-15 ®
Edition 1.0 2015-12
INTERNATIONAL
STANDARD
colour
inside
Metallic communication cable test methods –
Part 4-15: Electromagnetic compatibility (EMC) – Test method for measuring
transfer impedance and screening attenuation – or coupling attenuation with
triaxial cell
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.

IEC Central Office Tel.: [phone]
3, rue de Varembé Fax: [phone]
CH-1211 Geneva 20 [e-mail]
Switzerland 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.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing more than 30 000 terms and
Technical Specifications, Technical Reports and other definitions in English and French, with equivalent terms in 15
documents. Available for PC, Mac OS, Android Tablets and additional languages. Also known as the International
iPad. Electrotechnical Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a More than 60 000 electrotechnical terminology entries in
variety of criteria (reference number, text, technical English and French extracted from the Terms and Definitions
committee,…). It also gives information on projects, replaced clause of IEC publications issued since 2002. Some entries
and withdrawn publications. have been collected from earlier publications of IEC TC 37,

77, 86 and CISPR.
IEC Just Published - webstore.iec.ch/justpublished

Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: [e-mail].
IEC 62153-4-15 ®
Edition 1.0 2015-12
INTERNATIONAL
STANDARD
colour
inside
Metallic communication cable test methods –

Part 4-15: Electromagnetic compatibility (EMC) – Test method for measuring

transfer impedance and screening attenuation – or coupling attenuation with

triaxial cell
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.100; 33.120.10 ISBN 978-2-8322-3056-5

– 2 – IEC 62153-4-15:2015 © IEC 2015
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions. 8
4 Physical background . 10
5 Principle of the test methods . 10
5.1 General . 10
5.2 Transfer impedance . 11
5.3 Screening attenuation. 12
5.4 Coupling attenuation . 12
5.5 Tube in tube method . 13
6 Test procedures . 13
6.1 General . 13
6.2 Triaxial cell . 13
6.3 Cut off frequencies, higher order modes . 13
6.4 Test equipment . 14
6.5 Calibration procedure . 14
6.6 Test leads and connecting cables to DUT . 15
7 Sample preparation . 15
7.1 Coaxial connector or assembly or quasi-coaxial component . 15
7.2 Balanced or multipin connector or component . 15
7.3 Cable assemblies . 16
7.4 Other screened devices . 17
8 Transfer impedance (short – matched) . 17
8.1 General . 17
8.2 Principle block diagram of transfer impedance . 17
8.3 Measuring procedure . 18
8.4 Evaluation of test results . 18
8.5 Test report . 18
9 Screening attenuation . 19
9.1 General . 19
9.2 Impedance matching . 19
9.3 Measuring with matched conditions . 19
9.3.1 Procedure . 19
9.3.2 Evaluation of test results . 19
9.4 Measuring with mismatch . 20
9.4.1 General . 20
9.4.2 Evaluaton of test results . 20
9.5 Test report . 21
10 Coupling attenuation . 21
10.1 Procedure . 21
10.2 Expression of results . 21
10.3 Test report . 22
11 Coupling transfer function . 22
Annex A (informative) Principle of the triaxial test procedure . 23

Annex B (informative) Triaxial cell . 25
Annex C (informative) Cut off frequencies, higher order modes . 27
Annex D (informative) Coupling transfer function . 30
Annex E (informative) Attenuation versus scattering parameter S . 32
Annex F (informative) Application of a moveable shorting plane . 34
F.1 Effect of the measurement length on the measurement cut-off frequency . 34
F.2 Details of the movable shorting plane . 34
F.3 Measurement results . 36
Annex G (informative) Correction in case the receiver input impedance R is higher
than the characteristic impedance of the outer circuit Z . 37
Bibliography . 39

Figure 1 – Definition of Z . 8
T
Figure 2 – Principle depiction of the triaxial cell to measure transfer impedance and
screening attenuation . 11
Figure 3 – Principle depiction of the triaxial cell to measure transfer impedance and
screening attenuation of assemblies with tube in tube according to IEC 62153-4-7 . 11
Figure 4 – Preparation of balanced or multipin connectors for transfer impedance and
screening attenuation . 16
Figure 5 – Preparation of balanced or multipin connectors for coupling attenuation
measurement . 16
Figure 6 – Test set-up (principle) for transfer impedance measurement according to
test method B of IEC 62153-4-3 . 17
Figure A.1 – Principle test set-up to measure transfer impedance and screening
attenuation . 23
Figure A.2 – Equivalent circuit of the principle test set-up in Figure A.1 . 23
Figure B.1 – Principle depiction of the triaxial cell to measure transfer impedance and
screening attenuation at HV-assemblies with tube in tube according to IEC 62153-4-7 . 25
Figure B.2 – Example of different designs of triaxial cells . 26
Figure C.1 – Comparison of the measurements with tube and with triaxial cell of a RG
11 cable with single braid construction, linear scale . 28
Figure C.2 – Comparison of the measurements with tube and with triaxial cell of a cable
RG 11 with single braid construction, log scale . 29
Figure D.1 – Measured coupling transfer function of a braided screen vs. frequency
with the triaxial cell . 30
Figure E.1 – Measurement with HP8753D of S of a 3dB attenuator . 32
Figure E.2 – Measurement with ZVRE of S of a 3dB attenuator . 33
Figure F.1 – Crosssection of triaxial cell with movable shorting plane. 34
Figure F.2 – Crosscut of plane shortening housing and tube-in-tube . 35
Figure F.3 – Detail H of figure F.2: contact between plane and housing . 35
Figure F.4 – Detail G of figure F.2: contact between plane and tube-in-tube . 36
Figure F.5 – Compilation of transfer impedance test results with different shorting plane
distances . 36
Figure G.1 – Example of forward transfer scattering parameter S for different
impedances in the outer circuit where the receiver input impedance is 50Ω . 37
Figure G.2 – DUT with uniform cylindrical shape in the centre of the cell . 38

– 4 – IEC 62153-4-15:2015 © IEC 2015
Table 1 – IEC 62153-4-x, Metallic communication cable test methods – Test
procedures with triaxial test set-up . 10
Table C.1 – Resonance frequencies of different triaxial cells . 27

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
METALLIC COMMUNICATION CABLE TEST METHODS –

Part 4-15: Electromagnetic compatibility (EMC) – Test method
for measuring transfer impedance and screening attenuation –
or coupling attenuation with triaxial cell

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 IEC 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 of 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) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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 damage 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 62153-4-15 has been prepared by IEC technical committee 46:
Cables, wires, waveguides, R.F. connectors, R.F. and microwave passive components and
accessories.
The text of this standard is based on the following documents:
FDIS Report on voting
46/573/FDIS 46/586/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.

– 6 – IEC 62153-4-15:2015 © IEC 2015
A list of all the parts in the IEC 62153-4 series published under the general title Metallic
Communication Cable test methods – Electromagnetic compatibility (EMC), can be found on
the IEC website.
The committee has decided that the contents of this publication will remain unchanged until the
stability date indicated on the IEC website 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.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

METALLIC COMMUNICATION CABLE TEST METHODS –

Part 4-15: Electromagnetic compatibility (EMC) –
Test method for measuring transfer impedance and screening
attenuation – or coupling attenuation with triaxial cell

1 Scope
This part of IEC 62153 specifies the procedures for measuring with triaxial cell the transfer
impedance, screening attenuation or the coupling attenuation of connectors, cable assemblies
and components, e.g. accessories for analogue and digital transmission systems and
equipment for communication networks and cabling (in accordance with the scope of IEC
technical committee 46).
Measurements can be achieved by applying the device under test direct to the triaxial cell or
with the tube in tube method in accordance with IEC 62153-4-7.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
IEC 61196-1, Coaxial communication cables – Part 1: Generic specification – General,
definitions and requirements
IEC TS 62153-4-1:2013, Metallic communication cable test methods – Part 4-1:
Electromagnetic Compatibility (EMC) − Introduction to electromagnetic screening
measurements
IEC 62153-4-3, Metallic communication cable test methods – Part 4-3: Electromagnetic
compatibility (EMC) − Surface transfer impedance − Triaxial method
IEC 62153-4-4, Metallic communication cable test methods – Part 4-4: Electromagnetic
compatibility (EMC) – Shielded screening attenuation, test method for measuring of the
screening attenuation as up to and above 3 GHz
IEC 62153-4-7, Metallic communication cable test methods – Part 4-7: Electromagnetic
compatibility (EMC) – Test method for measuring the transfer impedance and the screening –
or the coupling attenuation – Tube in tube method
IEC 62153-4-8, Metallic communication cable test methods – Part 4-8: Electromagnetic
compatibility (EMC) – Capacitive coupling admittance
IEC 62153-4-9:2009, Metallic communication cable test methods – Part 4-9: Electromagnetic
compatibility (EMC) – Coupling attenuation of screened balanced cables, triaxial method
IEC 62153-4-10, Metallic communication cable test methods – Part 4-10: Shielded screening
attenuation test method for measuring the screening effectiveness of feed-troughs and
electromagnetic gaskets double coaxial method

– 8 – IEC 62153-4-15:2015 © IEC 2015
IEC TS 62153-4-16, Metallic communication cable test methods – Part 4-16: Extension of the
frequency range to higher frequencies for transfer impedance and to lower frequencies for
screening attenuation measurements using the triaxial set-up
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61196-1 and the
following apply.
3.1
triaxial cell
rectangular housing in analogy to the principles of the triaxial test procedure, consisting of a
non-ferromagnetic metallic material
Note 1 to entry: The triaxial test procedure is described in IEC 62153-4-3 and IEC 62153-4-4.
3.2
surface transfer impedance
Z
T
for an electrically short screen, quotient of the longitudinal voltage U induced to the inner
circuit by the current I fed into the outer circuit or vice versa [Ω] (see Figure 1)
Note 1 to entry: The value Z of an electrically short screen is expressed in ohms [Ω] or decibels in relation to
T
1 Ω.
I I
2 2
l < λ/10
U
IEC
Figure 1 – Definition of Z
T
U
Z = (1)
T
I
 
Z
T
 
Z dB(Ω)= 20⋅lg (2)
T
 
 1Ω 
 
3.3
effective transfer impedance
Z
TE
impedance defined as:
Z = max Z ± Z (3)
TE F T
where Z is the capacitive coupling impedance
F
3.4
screening attenuation
a
s
for electrically long devices, i.e. above the cut-off frequency, logarithmic ratio of the feeding
power P and the periodic maximum values of the coupled power P in the outer circuit
1 r,max
 
P
 
a = 10⋅lg Env (4)
s
 
 P 
r,max
 
where
Env is the minimum envelope curve of the measured values in dB
Note 1 to entry: The screening attenuation of an electrically short device is defined as:
150Ω
a = 20⋅lg (5)
s
Z
TE
where
150 Ω is the standardized impedance of the outer circuit.
3.5
coupling attenuation
a
c
for a screened balanced device, sum of the unbalance attenuation a of the symmetric pair and
u
the screening attenuation a of the screen of the device under test
s
Note 1 to entry: For electrically long devices, i.e. above the cut-off frequency, the coupling attenuation a is
c
defined as the logarithmic ratio of the feeding power P and the periodic maximum values of the coupled power
P in the outer circuit.
r,max
3.6
coupling length
length of cable which is inside the test jig, i.e. the length of the screen under test
Note 1 to entry: The coupling length is electrically short, if
c
λ
o
o
> 10⋅ ε or f < (6)
r1
L
10⋅ L⋅ ε
r1
or electrically long, if <
c
λ
o
o
≤ 2⋅ ε – ε or f > (7)
r1 r2
L
2⋅ L⋅ ε – ε
r1 r2
where
L is the effective coupling length in m;
λ is the free space wave length in m;
ε is the resulting relative permittivity of the dielectric of the cable;
r1
ε is the resulting relative permittivity of the dielectric of the secondary circuit;
r2
f is the frequency in Hz;
c is the velocity of light in free space.
– 10 – IEC 62153-4-15:2015 © IEC 2015
3.7
device under test
DUT
connector with mating connector and attached connecting cables or cable assembly consisting
of the assembly with their attached mated connectors and with connecting cables
4 Physical background
See 62153-4-1, 62153-4-3, 62153-4-4 and Annexes A to F.
5 Principle of the test methods
5.1 General
The IEC 62153-4-x series describes different test procedures to measure screening
effectiveness on communication cables, connectors and components.
Table 1 gives an overview about IEC 62153-4-x test procedures with the triaxial test set-up.
Table 1 – IEC 62153-4-x, Metallic communication cable test methods –
Test procedures with triaxial test set-up
IEC 62153- 4-x Metallic communication cable test methods – Electromagnetic compatibility (EMC)
IEC TS 62153-4-1 Introduction to electromagnetic screening measurements
IEC 62153-4-3 Surface transfer impedance – Triaxial method
IEC 62153-4-4 Shielded screening attenuation, test method for measuring of the screening attenuation a up
S
to and above 3 GHz
IEC 62153-4-7 Shielded screening attenuation test method for measuring the Transfer impedance Z and
T
the screening attenuation a or the coupling attenuation a of RF-connectors and assemblies
S C
up to and above 3 GHz, tube in tube method
IEC 62153-4-9 Coupling attenuation of screened balanced cables, triaxial method
IEC 62153-4-10 Shielded screening attenuation test method for measuring the screening effectiveness of
feedtroughs and electromagnetic gaskets double coaxial method
IEC 62153-4-15 Test method for measuring transfer impedance and screening attenuation – or coupling
attenuation with triaxial cell
IEC TS 62153-4-16 Extension of the frequency range to higher frequencies for transfer impedance and to lower
frequencies for screening attenuation measurements using the triaxial set-up

Larger connectors and cable assemblies do not fit into the commercial available test rigs of the
triaxial test procedures of the IEC 62153-4-x series according to Table 1, which have been
designed originally to measure transfer impedance and screening attenuation on
communication cables, connectors and assemblies.
Since rectangular housings with RF-tight caps are easier to manufacture than tubes, the
“triaxial cell” was designed to test larger components like connectors and assemblies. The
principles of the triaxial test procedures according to the IEC 62153-4-x series can be
transferred to rectangular housings. Tubes and rectangular housings can be operated in
combination in one test set-up, see Figure 2 and Figure 3.

DUT
Generator
Receiver
Test head with
screening cap
Connecting cable
Housing resp. triaxial cell
IEC
Figure 2 – Principle depiction of the triaxial cell to measure transfer
impedance and screening attenuation
In principle, the triaxial cell can be used in accordance with all triaxial procedures of Table 1,
where originally a cylindrical tube is used. The screening effectiveness of connectors,
assemblies or other components can be measured in principle in the tube as well as in the
triaxial cell. Test results of measurements with tube and with triaxial cell correspond well.
Generator
DUT
Receiver
Tube in tube
Connecting cable
Test head with
screening cap
Housing resp. triaxial cell
IEC
Figure 3 – Principle depiction of the triaxial cell to measure transfer
impedance and screening attenuation of assemblies
with tube in tube according to IEC 62153-4-7
The triaxial cell test set up is based on the triaxial system according to IEC 62153-4-3 and
IEC 62153-4-4 consisting of the DUT, a solid metallic housing and (optional) a RF-tight
extension tube. The matched device under test, DUT, which is fed by a generator forms the
disturbing circuit which may also be designated as the inner or the primary circuit.
The disturbed circuit, which may also be designated as the outer or the second circuit, is
formed by the outer conductor of the device under test, connected to the connecting cable (or
the tube in tube, if applicable) and a solid metallic housing or cell having the DUT in its axis.
5.2 Transfer impedance
The test determines the screening effectiveness of a shielded device by applying a well-defined
current and voltage to the screen of the cable, the assembly or the device under test and
measuring the induced voltage in secondary circuit in order to determine the surface transfer
impedance. This test measures only the galvanic and magnetic component of the transfer
impedance. To measure the electrostatic component (the capacitance coupling impedance),
the method described in IEC 62153-4-8 should be used.

– 12 – IEC 62153-4-15:2015 © IEC 2015
The triaxial method for the measurement of the transfer impedance is in general suitable in the
frequency range up to 30 MHz for a 1 m sample length and 100 MHz for a 0,3 m sample length,
which corresponds to an electrical length less than 1/6 of the wavelength in the sample. A
detailed description could be found in Clause 9 of IEC/TS 62153-4-1:2013 as well as in
IEC 62153-4-3.
5.3 Screening attenuation
The disturbing or primary circuit is the matched cable, assembly or component under test. The
disturbed or secondary circuit consists of the outer conductor (or the outermost layer in the
case of multiscreen cables or devices) of the cable or the assembly or the device under test
and a solid metallic housing, having the device under test in its axis (see Figure 3).
The voltage peaks at the far end of the secondary circuit have to be measured. The near end
of the secondary circuit is short-circuited. For this measurement, a matched receiver is not
necessary. The expected voltage peaks at the far end are not dependent on the input
impedance of the receiver, provided that it is lower than the characteristic impedance of the
secondary circuit. However, it is an advantage to have a low mismatch, for example, by
selecting of housings of sufficient size. A detailed description could be found in Clause 10 of
IEC/TS 62153-4-1:2013 as well as in IEC 62153-4-4.
5.4 Coupling attenuation
Balanced cables, connectors, assemblies or devices which are driven in the differential mode
may radiate a small part of the input power, due to irregularities in the symmetry. For
unscreened balanced cables, connectors, assemblies or devices, this radiation is related to the
unbalance attenuation a . For screened balanced cables, connectors or assemblies, the
u
unbalance causes a current in the screen which is then coupled by the transfer impedance and
capacitive coupling impedance into the outer circuit. The radiation is attenuated by the screen
of the component and is related to the screening attenuation a .
s
Consequently the effectiveness against electromagnetic disturbances of shielded balanced
cables, connectors or assemblies is the sum of the unbalance attenuation a of the pair and the
u
screening attenuation a of the screen. Since both quantities usually are given in a logarithmic
s
ratio, they may simply be added to form the coupling attenuation a :
c
a = a + a (8)
c u s
Coupling attenuation a is determined from the logarithmic ratio of the feeding power P and
c 1
the periodic maximum values (the envelope) of the power P (which may be radiated due to
r,max
the peaks of voltage U in the outer circuit):
 
P
 
a = 10⋅ lg Env (9)
c
 
P
 
r,max
 
where
Env is the minimum envelope curve of the measured values in dB.
The relationship of the radiated power P (related to the normalised impedance of the
r
=150Ω), to the measured power P received on the input impedance of the
environment Z
S 2
receiver R is:
P
R
r,max
(10)
=
P 2Z
2,max s
There will be a variation of the voltage U on the far end, caused by the electromagnetic
coupling through the screen and superposition of the partial waves caused by the surface
transfer impedance Z , the capacitive coupling impedance Z (travelling to the far and near
T F
end) and the totally reflected waves from the near end.
To feed the balanced device under test, a differential mode signal is necessary. This can be
achieved with a two port network analyser (generator and receiver) and a balun or a multiport
network analyser (two generators with 180° phase shift and one receiver). The procedure to
measure coupling attenuation with a multiport network analyser is under consideration.
5.5 Tube in tube method
If required, measurements according to IEC 62153-4-7 can also be achieved in the triaxial cell.
The measurements shall be performed in accordance with IEC 62153-4-7 but using the triaxial
cell instead of the tube fixture (see Figure 2 and Figure 3).
6 Test procedures
6.1 General
The measurements shall be carried out at the temperature of (23 ± 3) °C. The test method
determines the transfer impedance or the screening attenuation or the coupling attenuation of
a DUT by measuring in a triaxial test set-up according to IEC 62153-4-3 and IEC 62153-4-4.
6.2 Triaxial cell
The triaxial cell consists of a rectangular housing in analogy to the principles of the triaxial test
procedures according to IEC 62153-4-3 and IEC 62153-4-4. The material of the housing shall
be of non-ferromagnetic metallic material. The length of the housing should be preferably 1 m.
Reflexions of the transmitted signal may occur (in the outer circuit), due to the deviation of the
characteristic impedances. The plane of the short circuit at the near end (generator side)
should be therefore preferably direct at the wall of the housing.
At the receiver side, the transition of the housing to the coaxial system impedance
(50 Ω-system) should be also direct at the wall of the housing.
6.3 Cut off frequencies, higher order modes
The housing, respectively the triaxial cell, is in principle a cavity resonator which shows
different resonance frequencies, depending on its dimensions.
For a rectangular cavity resonator, the resonance frequencies can be calculated according to
equation (11). For this calculation, one of the parameters M,N may be set to zero. Conductive
parts inside the cavity resonator or a poor centering of the DUT in the triaxial cell may lead to
deviating resonance frequencies or to mute them.
2 2
   
c M N
f =   +  (11)
MNP
   
2 a b
   
where
M,N are the number of modes (even, 2 of 3 > 0);

– 14 – IEC 62153-4-15:2015 © IEC 2015
a,b,c are the dimensions of cavity;
c is the velocity of light in free space.
Measurements of screening attenuation can be achieved up to the first cut off frequency,
(M, N = 1).
The behaviour of the triaxial cell above the first cut off frequency is under consideration.
6.4 Test equipment
The measurements can be performed using a vector network analyser (VNA) or alternatively a
discrete signal generator and a selective measuring receiver.
The measuring equipment consists of the following:
a) a vector network analyser (with S-parameter test set) or alternatively
– a signal generator with the same characteristic impedance as the coaxial system of the
cable under test or with an impedance adapter and complemented with a power
amplifier if necessary for very high screening attenuation, and
– a receiver with optional low noise amplifier for very high screening attenuation.
b) Impedance matching circuit if necessary:
– primary side: nominal impedance of generator,
– secondary side: nominal impedance of the inner circuit,
– loss: >10 dB,
c) balun for impedance matching of unbalanced generator output signal to the characteristic
impedance of balanced cables for measuring the coupling attenuation. Requirements for
the balun are given in IEC 62153-4-9:2008, subclause 6.2. Alternatively a VNA with mixed
mode option may be used, see IEC/TR 61156-1-2,
Optional equipment is:
d) time domain reflectometer (TDR) with a rise time of less than 200 ps or network analyser
with maximum frequency up to 5 GHz and time domain capability.
6.5 Calibration procedure
The calibration shall be established at the same frequency points at which the measurement of
the transfer impedance is done, i.e. in a logarithmic frequency sweep over the whole frequency
range, which is specified for the transfer impedance.
When using a vector network analyser with S-parameter test-set, a full two port calibration
shall be established including the connecting cables used to connect the test set-up to the test
equipment. The reference planes for the calibration are the connector interface of the
connecting cables.
When using a (vector) network analyser without S-parameter test-set, i.e. by using a power
splitter, a THRU calibration shall be established including the test leads used to connect the
test set-up to the test equipment.
When using a separate signal generator and receiver, the composite loss of the test leads shall
be measured and the calibration data shall be saved, so that the results may be corrected.
 
P
 
a = 10⋅lg = –20⋅lg(S ) (12)
cal 21
 
P
 
where
a Is the attenuation obtained at the calibration procedure
cal
P is the power fed during calibration procedure;
is the power at the receiver during calibration procedure.
P
If amplifiers are used, their gain shall be measured over the above mentioned frequency range
and the data shall be saved.
If an impedance matching adapter or balun is used, the attenuation shall be measured over the
above- mentioned frequency range and the data shall be saved.
6.6 Test leads and connecting cables to DUT
Test leads and connecting cables to the DUT shall be well screened.
In case of measuring transfer impedance, the transfer impedance Z of the connecting cables
con
inside the test set-up can be measured separate either in the triaxial tube or in the triaxial cell,
expressed in mΩ/m, according to IEC 62153-4-3. The length of the connecting cables in the
set-up shall be measured, the transfer impedance Z calculated and be subtracted from the
con
measured transfer impedance of the DUT.
In case of screening attenuation or coupling attenuation, the screening attenuation or the
coupling attenuation of the connecting cables can be measured separate either in the triaxial
tube or in the triaxial cell, expressed in dB, according to IEC 62153-4-4 or IEC 62153-4-9.
The measured screening attenuation or coupling attenuation of the connecting cables inside
the set-up shall be at least 10 dB better than the measured value of the DUT.
7 Sample preparation
7.1 Coaxial connector or assembly or quasi-coaxial component
The connector or the assembly or the component under test shall be connected to its mating
part according to the specification of the manufacturer.
A well screened coaxial connecting cable shall be mounted to the connector, the assembly or
the component under test and/or its mating part(s). One end of the connecting cable shall be
connected to the test head of the test set-up and matched with the nominal characteristic
impedance of the DUT.
The screen of the other end of the connecting cable shall be connected to the wall of the
housing (the short circuit at the generator side).
In case of tube in tube procedure, the other end of the connecting cable shall be passed
through the rf-tight tube in tube and connected to the generator. On the side of the device
under test, the screen, the feeding cable shall be connected to the extension tube with low
contact resistance. On the generator side, the screen of the connecting cable shall not be
connected to the extension tube. The extension tube shall be connected to the wall of the
housing (the short circuit at the generator side).
7.2 Balanced or multipin connector or component
The device under test shall be connected to its mating part according to the specification of the
manufacturer.
A balanced or multi-conductor cable which is usually used with the connector or the device
under test shall be mounted to the connector under test and it’s mating part or to the device
under test according to the specification of the manufacturer.

– 16 – IEC 62153-4-15:2015 © IEC 2015
For the measurement of transfer impedance or screening attenuation, screened balanced or
multiconductor cables or multipin conductors or components are treated as a quasi-coaxial
system. Therefore, at the open ends of the feeding cable, all conductors of all pairs shall be
connected together. All screens, also those of individually screened pairs or quads, shall be
connected together at both ends. All screens shall be connected over the whole circumference
(see Figure 4 and Figure 5).
One end of the connecting cable shall then be connected to the test head where the connecting
cable is matched with the characteristic impedance of the DUT.
Mated connector under test
Load resistor
Screen
IEC
Figure 4 – Preparation of balanced or multipin connectors
for transfer impedance and screening attenuation
When measuring the coupling attenuation, the connecting cable shall be fed by a balun or by
VNA with multimode option (under consideration). The pair under test shall be matched by a
symmetrical/asymmetrical load. The pairs which are not under test shall be left open.
Mated connector under test
Balun (or multiport VNA)
Symmetrical
asymmetrical
load
Screen of feeding cable
IEC
Figure 5 – Preparation of balanced or multipin connectors
for coupling attenuation measurement
7.3 Cable assemblies
The connectors of the assembly under test shall be connected with its mating parts on both
ends respectively on one end in case of single ended assemblies, according to the
specification of the manufacturer.
The mating connectors shall be connected with well screened coaxial feeding cables.
In case of multi-pin conductor assemblies, all conductors of the assembly under test shall be
short circuited on both ends in the mating connector. If the assembly under test is connected in

its intended use direct to a specific unit and no mating connecter is available, the manufacturer
of the assembly shall provide an appropriate mating connector or an appropriate adaptation.
The mating connector or the adaption shall be well screened, at least 10 dB better than the
device under test. Care shall be taken, that the connection of the connecting cable to the
mating connector or the adaption is well screened.
7.4 Other screened devices
The screening effectiveness of other shielded or screened devices
...