IEC TR 62153-4-0:2007

Metallic communication cable test methods - Part 4-0: Electromagnetic compatibility (EMC) - Relationship between surface transfer impedance and screening attenuation, recommended limits

It describes important background material used during the revision of IEC 61196-1:1995, Clause 14, Guidance for surface transfer impedance and screening attenuation limits for flexible r.f. cables. It is also given the relationship between surface transfer impedance (ZT) and screening attenuation (as), also measurements of ZT and as are provided to show the correlation of mean screening attenuation between 200 MHz and 500 MHz and ZT at both 30 MHz and 300 MHz.

Méthodes d'essai des câbles métalliques de communication - Partie 4- 0: Compatibilité électromagnétique (CEM) - Relation entre l'impédance de transfert en surface et l'affaiblissement d'écran, limites recommandées

Il fournit les informations générales utiles utilisées au cours de la révision de la CEI 61196-1:1995, Article 14, Instructions pour l'impédance de transfert en surface et les limites d'affaiblissement d'écran pour les câbles r.f. souples. Il est egalément donnée la relation entre l'impédance en transfert en surface (ZT) et l'affaiblissement d'écran (as) ; de même, les mesures de ZT et as sont fournies pour montrer la corrélation de l'affaiblissement moyen de l'écrantage entre 200 MHz et 500 MHz et ZT à 30 MHz et 300 MHz.

General Information

• Status: Published
• Publication Date: 13-Nov-2007
• 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: PPUB - Publication issued
• Start Date: 14-Nov-2007
• Completion Date: 15-Jan-2008

Relations

• Replaces: IEC TR 62064:1999 - Radio-frequency cables - Relationship between the surface transfer impedance and screening attenuation (A background paper to the recommended limits in IEC 61196-1, clause 14)
• Effective Date: 05-Sep-2023

Overview

IEC TR 62153-4-0:2007 is a technical report published by the International Electrotechnical Commission (IEC) focusing on metallic communication cable test methods related to electromagnetic compatibility (EMC). Specifically, it explores the relationship between surface transfer impedance (ZT) and screening attenuation (as) of flexible radio frequency (r.f.) cables, and provides recommended limits for these parameters. The report supports and updates guidance laid out in IEC 61196-1:1995, Clause 14.

This document is essential for stakeholders aiming to optimize cable designs for effective electromagnetic shielding and to ensure signal integrity in communication systems. It presents measurement data, theoretical relationships, and practical recommendations for ensuring cable metallic shielding meets EMC requirements.

Key Topics

• Surface Transfer Impedance (ZT): The impedance at the cable surface affecting how electromagnetic interference is transferred along the cable. It plays a crucial role in shielding effectiveness.
• Screening Attenuation (as): A measure of how well a cable can attenuate electromagnetic fields, expressed in decibels (dB).
• Correlation between ZT and as: The report demonstrates how these parameters relate, particularly in the frequency range 200 MHz to 500 MHz for screening attenuation and at 30 MHz and 300 MHz for surface transfer impedance.
• Measurement Techniques: Details of various measurement setups, including the absorbing clamp method, which simulates real-world cable environments.
• Effects of Velocity Differences: Highlights that the relative propagation velocity difference between the inner and outer cable conductors (Δv/v) impacts screening attenuation, with a recommended standardized velocity difference of 10%.
• Cable Construction Types: Discusses variations in braiding and foil-braid shielding structures and their impact on impedance and attenuation.
• Recommended Limits:
  • For single braided cables: ZT limits around 100 mΩ/m at 30 MHz to ensure effective screening.
  • For foil-braid cables: ZT ≤ 5 mΩ/m at 5 MHz and ≤ 50 mΩ/m at DC is recommended for low-frequency performance.
  • For double braided cables: Screening attenuation targets around 90 dB with absorbing clamp measurement.

Applications

The IEC TR 62153-4-0:2007 standard is widely applied in the:

• Design and testing of RF communication cables to ensure compliance with electromagnetic compatibility requirements.
• Cable manufacturing industry, where optimizing shielding construction helps achieve low transfer impedance and high screening attenuation.
• CATV (Cable Television) network systems, particularly as these systems increasingly utilize frequencies between 5 MHz and 30 MHz.
• Electromagnetic interference (EMI) mitigation in metallic cables used in telecommunications, data transmission, and industrial environments.
• Quality assurance and standard compliance, by providing testing guidance and recommended limits that support international standardization and facilitate product certification.

Related Standards

• IEC 61196-1:1995 – Flexible r.f. cables and their surface transfer impedance and screening attenuation limits.
• IEC/TR 61917 – Introduction to electromagnetic screening measurements for cables and related components.
• Series IEC 62153 – Metallic communication cable test methods covering various aspects of cable performance and measurement.
• ISO/IEC Directives, Part 2 – Guidelines used in drafting international electrotechnical standards.
• Industry-specific EMC standards related to telecommunications and broadcasting infrastructure.

---

By adhering to IEC TR 62153-4-0:2007, manufacturers and engineers can ensure metallic communication cables provide effective electromagnetic shielding-resulting in reduced interference, improved signal quality, and compliance with international EMC norms. This contributes to the reliability and performance of modern communication systems across diverse fields.

Standards Content (Sample)

IEC/TR 62153-4-0
Edition 1.0 2007-11
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
Metallic communication cable test methods –
Part 4-0: Electromagnetic compatibility (EMC) – Relationship between surface
transfer impedance and screening attenuation, recommended limits

Méthodes d’essai des câbles métalliques de communication –
Partie 4-0: Compatibilité électromagnétique (CEM) – Relation entre l’impédance
de transfert en surface et l’affaiblissement d’écran, limites recommandées

IEC/TR 62153-4-0:2007
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IEC/TR 62153-4-0
Edition 1.0 2007-11
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
Metallic communication cable test methods –
Part 4-0: Electromagnetic compatibility (EMC) – Relationship between surface
transfer impedance and screening attenuation, recommended limits

Méthodes d’essai des câbles métalliques de communication –
Partie 4-0: Compatibilité électromagnétique (CEM) – Relation entre l’impédance
de transfert en surface et l’affaiblissement d’écran, limites recommandées

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
N
CODE PRIX
ICS 33.100; 33.120.10 ISBN 2-8318-9363-1

– 2 – TR 62153-4-0 © IEC:2007
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
METALLIC COMMUNICATION CABLE TEST METHODS –

Part 4-0: Electromagnetic compatibility (EMC) –
Relationship between surface transfer impedance and screening
attenuation, recommended limits

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
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consensus of opinion on the relevant subjects since each technical committee has representation from all
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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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.
The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a technical report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC 62153-4-0, which is a technical report, has been prepared by IEC technical committee 46:
Cables, wires, waveguides, R.F. connectors, R.F. and microwave passive components and
accessories.
This publication cancels and replaces IEC/TR 62064, published in 1999.

TR 62153-4-0 © IEC:2007 – 3 –
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
46/197/DTR 46/252/RVC
Full information on the voting for the approval of this technical report 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.
A list of all parts of the IEC 62153 series, under the general title: Metallic communication cable
test methods, can be found on the IEC website.
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.
– 4 – TR 62153-4-0 © IEC:2007
METALLIC COMMUNICATION CABLE TEST METHODS –

Part 4-0: Electromagnetic compatibility (EMC) –
Relationship between surface transfer impedance and screening
attenuation, recommended limits

1 Scope
This technical report describes important background material used during the revision of
IEC 61196-1:1995, Clause 14, Guidance for surface transfer impedance and screening
attenuation limits for flexible r.f. cables.
In this technical report, the relationship between surface transfer impedance (Z ) and
T
screening attenuation (a ) is given, also measurements of Z and a are provided to show the
s T s
at both
correlation of mean screening attenuation between 200 MHz and 500 MHz and Z
T
30 MHz and 300 MHz.
The sensitivity of a to the relative velocity difference between the inner and outer system is
s
shown. The cable data sheet should show the a values in a standardized form
s
– Δv/v = 10 % and the characteristic impedance of the outer system is 150 Ω. It is also shown
that a relative velocity difference change from 10 % to 40 % gives an improvement of 12 dB in
screening attenuation.
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/TR 61917, Cables, cable assemblies and connectors – Introduction to electromagnetic
(EMC) screening measurements
3 General
At high frequencies, when the surface transfer impedance Z and effective transfer
T
impedance Z = Z ±Z increase 6 dB per octave, the relationship to the screening
TE F T
n, f
attenuation a is frequency independent and can be written as (see also Figure 1):
s
a = −20 × log T (1)
n
s 10
n
f
f
Z Z c
T T o
= −20 × log = −20 × log (2)
10 10
l l
Z Z ω ε ± ε
1 2 r2 r1
Z Z ω ±
1 2
v v
2 1
and
TR 62153-4-0 © IEC:2007 – 5 –
U / Z
2n 2
f
T = (3)
n
f U / Z
1 1
where
l is the length of the cable under test;
D is the cylinder diameter;
E is the source voltage;
T are the coupling transfer functions;
n,f
‘n’ is for the near end and ‘f’ for the far end;
U is the inner circuit near end voltage;
1n
U is the outer circuit near end voltage;
2n
U is the inner circuit far end voltage;
1f
U is the outer circuit far end voltage;
2f
Z is the characteristic impedance of the cable;
Z is the impedance of the outer circuit;
ε is the cable dielectric permittivity;
r1
ε is the permittivity of the outer circuit;
r2
c is the velocity of light in vacuum;
o
ω is the radian frequency;
v is the propagation velocity of the inner circuit;
v is the propagation velocity of the outer circuit;
Z is the capacitive coupling impedance;
F
Z is the surface transfer impedance;
T
Z is the effective transfer impedance.
TE
n, f
l
+
E
Z U
2 U 2f
Z
2n
U
1n
Z Z
U
1f
D
Z
1 v
Z v
IEC  2143/07
Key
1 inner circuit, cable under test
2 outer circuit, formed by test line or cylinder or the outer environment as in the absorbing clamp method
Figure 1 – Concept of screening measurement set-ups

– 6 – TR 62153-4-0 © IEC:2007
When the capacitive coupling impedance Z is present (spaces in the outer conductor), Z
F T
shall be substituted by Z .
TE
"+" sign is for the near end and "–" sign for the far end. Z and Z are the impedances of the
1 2
inner and outer system and v and v the corresponding velocities.
1 2
Screening attenuation a is a reliable measure of screening efficiency when the frequency is
s
constant. This is true when Z or Z increases 6 dB/octave and the following criterion is
T TE
fulfilled:
λ
o
l ≥ (4)
n
f
π ε ± ε
r1 r2
where λ is the wave length in free space.
o
At lower frequencies when l is smaller than that found from (4), the coupling attenuation is:
(Z ±Z ) × l
F T
A = −20 × log T = −20 × log (5)
n
s 10 10
n
f 2 Z Z
f 1 2
More detailed information on the above equations is given in the IEC/TR 61917.
4 Correlation between measured screening attenuation a and measured

s
surface transfer impedances at 30 MHz and 300 MHz
Z and a were measured using the same cable construction. Figures 2, 3 and 4 show the
T s
correlation between a (mean value between 200 MHz and 500 MHz) and the Z values
s T
correspondingly at 30 MHz and 300 MHz.
In Figure 5, typical Z curves are shown. For single and double braided outer conductors, the
T
6 dB/octave increase is reached at 30 MHz but for foil-braid constructions at 30 MHz, Z can
T
still be decreasing. The effect of this can be clearly seen when comparing the test results in
Figures 2, 3 and 4 for the foil-braid cables. The correlation between a and Z (30 MHz) is
s T
poor, but much better between a and Z (300 MHz). For single and double braided cables, the
s T
correlation is equally good for 30 MHz and 300 MHz. The increase in the values of Z which
T
should have been 10 fold (20 dB) is somewhat lower. The full 6 dB/octave increase in Z
T
between 30 MHz and 300 MHz has not been reached for all single and double braided cables.
The Z (a ) correlation line slope from Equations (1) and (2) is –20 dB/decade.
T s
One reason for the spread in correlation is the strong effect of the velocity differences v – v
2 1
on the a value. To demonstrate this, two lines are shown for 40 % and one for 10 % relative
s
velocity difference (|v – v |/v ). Also, the outer circuit impedance has been altered from
2 1 1
300 Ω to 150 Ω.
Other reasons for the wide spread of the correlation points are that only the cable construction
has been kept the same, but the tested samples are different. It is impossible to use the same
samples in Z and a measurements because of the required difference in length of the cable

T s
under test (CUT). Even if the samples had been the same, a difference of ±6 dB would exist
when the CUT is removed from the test fixture and then remounted.
As shown above, the screening attenuation a is dependent on the outer circuit propagation
s
velocity and to a lesser extent on the impedance, and decreases rapidly when the velocities v
TR 62153-4-0 © IEC:2007 – 7 –
and v approach each other. For these reasons, it has been recommended that a shall also be
1 s
given in standardized conditions a where the outer circuit velocity differs by 10 % from the
sn
inner circuit velocity, and the outer circuit impedance is 150 Ω.
It can be seen from Figures 2 and 3 that the difference is about 10 dB. A drop in relative
velocity difference from 40 % to 10 % causes a decrease of 12 dB in a . A decrease in
s
impedance of 50 % causes an increase in a of 3 dB.
s
The values of the standardized condition 10 % relative velocity difference / 150 Ω have been
shown to be that of a typical cable tray surrounding. Normally, the measurement conditions of
the absorbing clamp set-up give approximately a 10 dB improvement value for a .
s
Figures 5, 6 and 7 show typical test results for single braided, double braided and foil-braid
outer conductor constructions.
5 Recommended limits for surface transfer impedance and screening
attenuation
In Clause 14 of IEC 61196-1:1995, Table 5 provides the recommended limits. To reach the
limit of 100 mΩ/m at 30 MHz for single braided cables, some optimization is needed, but even
values below 50 mΩ/m are not difficult to obtain. A guide for optimization of single braided
outer conductors is in preparation by the IEC. Some older cable design standards have
requirements for too great a screen coverage, for example, too much copper in the braid. They
are so heavily overbraided that a Z of 300 mΩ/m at 30 MHz is common.
T
To reach an a by an absorbing clamp measured screening attenuation of 90 dB for double
s
braided cables, some optimization is needed. In CATV networks, an a higher than 85 dB is
s
under discussion and an optimized double braided construction may fulfil the requirement.
When good screening is needed below 30 MHz, the so-called superscreened construction is
available, i.e. μ-metal tape sandwiched between two braids.
The most commonly used cable construction, when good screening at relatively high
frequencies is needed, is the foil-braid type. A copper or aluminium foil of suitable thickness
and overlap should be used to meet the screening values required.
At frequencies below 30 MHz, the screening properties should be defined at an upper limit of
the transfer impedance.
For foil-braid constructions, a Z ≤ 5 mΩ/m at 5 MHz and ≤ 50 mΩ/m at d.c. is recommended.
T
As it is becoming more common to utilize the 5 MHz to 30 MHz return path of the CATV
systems, it is important to specify the screening properties below 30 MHz. The relevant values
should be calculated in cooperation between IEC TC 46 and IEC TC 100/TA5.

– 8 – TR 62153-4-0 © IEC:2007
Measured Z (30 MHz) versus absorbing clamp measured
T
mean a (200 MHz to 500 MHz) value of same type of cable
s
1 000
Z (sb,30 MHz)
T
Z (db,30 MHz)
T
Z (fb,30 MHz)
T
a (Z ; Z = 300 Ω, v = 280 Mm/s)
s T 2 2
a (Z ; Z = 150 Ω, v = 220 Mm/s)
sn T 2 2
a (Z ; Z = 300 Ω, v = 220 Mm/s)
s’ T 2 2
0,1
0 20 40 60 80 100
Measured mean a (200 MHz to 500 MHz)  [dB]
s
IEC  2144/07
Figure 2 – Measured surface transfer impedance versus measured mean screening
attenuation and the calculated relation between Z and a when Z is directly
T s T
proportional to frequency at high frequencies

Z Z c
T T o
(6)
a = −20 × log = −20 × log
s 10 10
1 1
Z Z ω ε − ε
1 2 r2 r1
Z Z ω −
1 2
v v
2 1
where
Z = 75 Ω;
v = 200 Mm/s, assumed for the cable under test;
Z = 300 Ω or 150 Ω;
v = 220 Mm/s ( Δv/v = 10 %) or 280 Mm/s (ε =1,15 ; Δv/v = 40 %);
2 1 r2 1
c = 300 Mm/s.
o
Measured Z (30 MHz)  [mΩ/m]
T
TR 62153-4-0 © IEC:2007 – 9 –
Measured Z (30 MHz) line injection results versus absorbing clamp measured

TEf
mean a (200 MHz to 500 MHz) and the calculated relationbetween Z and a
s TEf s
when Z is directly proportional to frequency at high frequencies
TEf
1 000
Z (sb,30 MHz)
T
Z (db,30 MHz)
T
Z (fb,30 MHz)
T
a (Z ; Z = 300 Ω, v = 280 Mm/s)
s T 2 2
a (Z ; Z = 150 Ω, v = 220 Mm/s)
sn T 2 2
a (Z ; Z = 300 Ω, v = 220 Mm/s)
s’ T 2 2
0,1
0 20 40 60 80 100
Mean a (200 MHz to 500 MHz)  [dB]

s
IEC  2145/07
Figure 3 – Line-injection versus absorption clamp results at 30 MHz and the calculated
relation between Z and a when Z is directly proportional to frequency
TEf s TEf
Z Z c
TEf TEf o
a = −20 × log = −20 × log (7)
s 10 10
1 1
Z Z ω ε − ε
1 2 r2 r1
Z Z ω −
1 2
v v
2 1
where
Z = 75 Ω;
v = 200 Mm/s assumed for the cable under test;
Z = 300 Ω or 150 Ω;
v = 220 Mm/s (Δv/v = 10 %) or 280 Mm/s (ε = 1,15; Δv/v = 40 %);
2 1 r2 1
c = 300 Mm/s.
o
Measured Z (30 MHz)  [mΩ/m]
TEf
– 10 – TR 62153-4-0 © IEC:2007

Measured Z (300 MHz) line injection result versus absorbing clamp

TEf
measured mean a (200 MHz to 500 MHz) when Z is directly
s TEf
proportional to frequency at high frequencies
1 000
Z (sb,300 MHz)
T
Z (db,300 MHz)
T
Z (fb,300 MHz)
T
a (Z ; Z = 300 Ω, v = 280 Mm/s)
s T 2 2
a (Z ; Z = 150 Ω, v = 220 Mm/s)
sn T 2 2
a (Z ; Z = 300 Ω, v = 220 Mm/s)
s’ T 2 2
0,1
0 20 40 60 80 100 120
Measured mean a (200 MHz to 500 MHz)  [dB]

s
IEC  2146/07
Figure 4 – Line-injection versus absorption clamp results at 300 MHz and the calculated
relation between Z and a when Z is directly proportional to frequency
TEf s TEf
Z Z c
TEf TEf o
a = −20 × log = −20 × log (8)
s 10 10
1 1
Z Z ω ε − ε
1 2 r2 r1
Z Z ω −
1 2
v v
2 1
where
Z = 75 Ω;
v = 200 Mm/s assumed for the cable under test;
Z = 300 Ω or 150 Ω;
v = 220 Mm/s(Δv/v = 10 %) or 280 Mm/s (ε =1,15; Δv/v = 40 %);
2 1 r2 1
c = 300 Mm/s.
o
Measured Z (300 MHz)  [mΩ/m]
TEf
TR 62153-4-0 © IEC:2007 – 11 –

sb
20 dB/dec sbo
db
⏐Z ⏐
T
Log scale
fb
sba
ss
Log f
f f (30 MHz) f (300 MHz)
r
IEC  2147/07
Key
f typically 1.10 MHz
...