IEC TR 62153-4-1:2010

IEC/TR 62153-4-1 ®
Edition 2.0 2010-05
TECHNICAL
REPORT
colour
inside
Metallic communication cable test methods –
Part 4-1: Electromagnetic compatibility (EMC) – Introduction to electromagnetic
(EMC) screening measurements
IEC/TR 62153-4-1:2010(E)
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IEC/TR 62153-4-1 ®
Edition 2.0 2010-05
TECHNICAL
REPORT
colour
inside
Metallic communication cable test methods –
Part 4-1: Electromagnetic compatibility (EMC) – Introduction to electromagnetic
(EMC) screening measurements
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XB
ICS 33.100, 33.120.10 ISBN 978-2-88910-918-0
– 2 – TR 62153-4-1 © IEC:2010(E)
CONTENTS
FOREWORD.5
1 Scope.7
2 Normative references.7
3 Electromagnetic phenomena.8
4 The intrinsic screening parameters of short cables .10
4.1 General .10
4.2 Surface transfer impedance, Z .10
T
4.3 Capacitive coupling admittance, Y .10
C
4.4 Injecting with arbitrary cross-sections.12
4.5 Reciprocity and symmetry.12
4.6 Arbitrary load conditions .12
5 Long cables – coupled transmission lines.12
6 Transfer impedance of a braided wire outer conductor or screen .20
7 Test possibilities .26
7.1 General .26
7.2 Measuring the transfer impedance of coaxial cables.26
7.3 Measuring the transfer impedance of cable assemblies.26
7.4 Measuring the transfer impedance of connectors .27
7.5 Calculated maximum screening level .27
8 Comparison of the frequency response of different triaxial test set-ups to measure
the transfer impedance of cable screens .32
8.1 General .32
8.2 Physical basics.32
8.2.1 Triaxial set-up.32
8.2.2 Coupling equations .35
8.3 Simulations.35
8.3.1 General .35
8.3.2 Simulation of the standard and simplified methods according to
EN 50289-1-6, IEC 61196-1 (method 1 and 2) and IEC 62153-4-3
(method A).36
8.3.3 Simulation of the double short circuited methods.43
8.4 Conclusion .51
9 Background of the shielded screening attenuation test method (IEC 62153-4-4) .52
9.1 General .52
9.2 Objectives .52
9.3 Theory of the triaxial measuring method.53
9.4 Screening attenuation .58
9.5 Normalised screening attenuation .59
9.6 Measured results .60
9.7 Comparison with absorbing clamp method .62
9.8 Practical design of the test set-up .63
9.9 Influence of mismatches .64
Annex A (normative) List of symbols.67
Bibliography .70

rE,rH
t t
Figure 1 – Total electromagnetic field () .8

TR 62153-4-1 © IEC:2010(E) – 3 –
Figure 2 – Defining and measuring screening parameters – A triaxial set-up .9
Figure 3 – Equivalent circuit for the testing of Z .11
T
Figure 4 – Equivalent circuit for the testing of Y = j ωC .11
c T
Figure 5 – Electrical quantities in a set-up that is matched at both ends .12
Figure 6 – The summing function S{L·f} for near and far end coupling.16
Figure 7 – Transfer impedance of a typical single braid screen .17
Figure 8 – The effect of the summing function-coupling transfer function of a typical
single braid screen cable.17
Figure 9 – Calculated coupling transfer functions T and T for a single braid – Z = 0 .18
n f F
Figure 10 – Calculated coupling transfer functions T and T for a single braid – Im(Z )
n f T
is positive and Z = +0,5 × Im (Z ) at high frequencies .18
F T
Figure 11 – Calculated coupling transfer functions T and T for a single braid – Im(Z )
n f T
is negative and Z = –0,5 × Im(Z ) at high frequencies .19
F T
Figure 12 – L·S: the complete length dependent factor in the coupling function T .20
Figure 13 – Transfer impedance of typical cables .21
Figure 14 – Magnetic coupling in the braid Complete flux.22
Figure 15 – Magnetic coupling in the braid Left-hand lay contribution .22
Figure 16 – Magnetic coupling in the braid Right-hand lay contribution.22
Figure 17 – Complex plane, Z = Re Z + j Im Z , frequency f as parameter .23
T T T
Figure 18 – Magnitude (amplitude), | Z (f) | .23
T
Figure 19 – Typical Z (time) step response of an overbraided and underbraided single
T
braided outer conductor of a coaxial cable.
Figure 20 – Z equivalent circuits of a braided wire screen .25
T
Figure 21 – Comparison of signal levels in a generic test setup .28
Figure 22 – Triaxial set-up for the measurement of the transfer impedance Z .32
T
Figure 23 – Equivalent circuit of the triaxial set-up.33
Figure 24 – Simulation of the frequency response for g.37
Figure 25 – Simulation of the frequency response for g.37
Figure 26 – Simulation of the frequency response for g.38
Figure 27 – Simulation of the frequency response for g.38
Figure 28 – Simulation of the 3 dB cut off wavelength (L/λ ) .39
Figure 29 – Interpolation of the simulated 3 dB cut off wavelength (L/λ ).40
Figure 30 – 3 dB cut-off frequency length product as a function of the dielectric
permittivity of the inner circuit (cable) .41
Figure 31 – Measurement result of the normalised voltage drop of a single braid screen
in the triaxial set-up.42
Figure 32 – Measurement result of the normalised voltage drop of a single braid screen
in the triaxial set-up.43
Figure 33 – Triaxial set-up (measuring tube), double short circuited method .44
Figure 34 – Simulation of the frequency response for g.45
Figure 35 – Simulation of the frequency response for g.45
Figure 36 – Simulation of the frequency response for g.46
Figure 37 – Simulation of the frequency response for g.46
Figure 38 – Interpolation of the simulated 3 dB cut off wavelength (L/λ ).47
– 4 – TR 62153-4-1 © IEC:2010(E)
Figure 39 – 3 dB cut-off frequency length product as a function of the dielectric
permittivity of the inner circuit (cable) .48
Figure 40 – Simulation of the frequency response for g.49
Figure 41 – Interpolation of the simulated 3 dB cut off wavelength (L/λ ).50
Figure 42 – 3 dB cut-off frequency length product as a function of the dielectric
permittivity of the inner circuit (cable) .50
Figure 43 – Definition of transfer impedance.52
Figure 44 – Definition of coupling admittance .52
Figure 45 – Triaxial measuring set-up for screening attenuation.53
Figure 46 – Equivalent circuit of the triaxial measuring set-up.54
Figure 47 – Calculated voltage ratio for a typical braided cable screen.55
Figure 48 – Calculated periodic functions for ε = 2,3 and ε = 1,1 .56
r1 r2
Figure 49 – Calculated voltage ratio-typical braided cable screen.57
Figure 50 – Equivalent circuit for an electrical short part of the length Δl and negligible
capacitive coupling.58
Figure 51 – a of single braid screen, cable type RG 58, L = 2 m .61
s
Figure 52 – a of single braid screen, cable type RG 58, L = 0,5 m .61
s
Figure 53 – a of cable type HF 75 0,7/4,8 02YCY .62
s
Figure 54 – a of cable type HF 75 1,0/4,8 02YCY .62
s
Figure 55 – a of double braid screen, cable type RG 223.62
s
Figure 56 – Schematic for the measurement of the screening attenuation a .64
s
Figure 57 – Short circuit between tube and cable screen of the CUT.64
Figure 58 – Triaxial set-up, impedance mismatches.65
Figure 59 – Calculated voltage ratio including multiple reflections caused by the
screening case.66
Figure 60 – Calculated voltage ratio including multiple reflections caused by the
screening case.66

Table 1 – The coupling transfer function T (coupling function).15
Table 2 – Screening effectiveness of cable test methods for surface transfer impedance Z .30
T
Table 3 – Load conditions of the different set-ups.34
Table 4 – Parameters of the different set-ups .36
Table 5 – Cut-off frequency length product .40
Table 6 – Typical values for the factor v, for an inner tube diameter of 40 mm and a
generator output impedance of 50 Ω.44
Table 7 – Cut-off frequency length product .47
Table 8 – Material combinations and the factor n .49
Table 9 – Cut-off frequency length product .50
Table 10 – Cut-off frequency length product for some typical cables in the different set-ups.51
Table 11 – Δa in dB for typical cable dielectrics .60
Table 12 – Comparison of results of some coaxial cables .63

TR 62153-4-1 © IEC:2010(E) – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
METALLIC COMMUNICATION CABLE TEST METHODS –

Part 4-1: Electromagnetic compatibility (EMC) –
Introduction to electromagnetic (EMC) screening measurements

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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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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
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6) All users should ensure that they have the latest edition of this publication.
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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.
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/TR 62153-4-1, 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 second edition cancels and replaces the first edition published in 2007. The significant
change is a new clause on the background of the shielded screening attenuation test method.

– 6 – TR 62153-4-1 © IEC:2010(E)
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
46/331/DTR 46/350/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
stability 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.

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.

TR 62153-4-1 © IEC:2010(E) – 7 –
METALLIC COMMUNICATION CABLE TEST METHODS –

Part 4-1: Electromagnetic compatibility (EMC) –
Introduction to electromagnetic (EMC) screening measurements

1 Scope
Screening (or shielding) is one basic way of achieving electromagnetic compatibility (EMC).
However, a confusingly large number of methods and concepts is available to test for the
screening quality of cables and related components, and for defining their quality. This
technical report gives a brief introduction to basic concepts and terms trying to reveal the
common features of apparently different test methods. It should assist in correct interpretation
of test data, and in the better understanding of screening (or shielding) and related
specifications and standards.
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 60096-1:1986, Radio-frequency cables – Part 1: General requirements and measuring
methods
Amendment 2 (1993)
IEC 60096-4-1, Radio-frequency cables – Part 4: Specification for superscreened cables –
Section 1: General requirements and test methods
IEC 60169-1-3, Radio frequency connectors – Part 1: General requirements and measuring
methods – Section 3: Electrical tests and measuring procedures – Screening effectiveness
IEC 61196-1:1995, Radiofrequency cables – Part 1: Generic specification – General,
definitions, requirements and test methods
IEC 61726, Cable assemblies, cables, connectors and passive microwave components –
Screening attenuation measurement by the reverberation chamber method
IEC 62153-4-3, Metallic communication cables 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 a up to and above 3 GHz
s
IEC 62153-4-5, Metallic communication cable test methods – Part 4-5: Electromagnetic
compatibility (EMC) – Coupling or screening attenuation – Absorbing clamp method
EN 50289-1-6, Communication cables – Specification for test methods – Electrical test
methods – Electromagnetic performance

– 8 – TR 62153-4-1 © IEC:2010(E)
3 Electromagnetic phenomena
It is assumed that if an electromagnetic field is incident on a screened cable, there is only weak
coupling between the external field and that inside, and that the cable diameter is very small
compared with both the cable length and the wavelength of the incident field. The superposition
of the external incident field and the field scattered by the cable yields the total electromagnetic
r r
field ()E ,H in Figure 1. The total field at the screen's surface may be considered as the
t t
source of the coupling: electric field penetrates through apertures by electric or capacitive
coupling; also magnetic fields penetrate through apertures by inductive or magnetic coupling.
Additionally, the induced current in the screen results in conductive or resistive coupling.

r r
()E ,H
s s
r r r
()E ,H E
i i
t
r
r
H
t
n
σ
J
X
IEC  893/10
Key
r r
J induced surface current density- (A/m)
()E ,H incident electromagnetic field
i i
r r
σ induced surface charge density- (C/m )
()E ,H scattered electromagnetic field
s s
r r r
n unit vector normal to the surface
()E ,H total electromagnetic field
t t
x positive axial cable direction ε , ε permittivity, free space and relative
o r
rE,rH
t t
Figure 1 – Total electromagnetic field ()
r r r r r r
()E ,H =(E ,H)+(E ,H) (1)
t t i i s s
r
r
J = n ⋅ H (2)
t
r
r
σ = n ⋅ E ε ε (3)
t o r
TR 62153-4-1 © IEC:2010(E) – 9 –
As the field at the surface of the screen is directly related to density of surface current and
r r
surface charge, the coupling may be assigned either to the total field ()E ,H or to the surface
t t
current- and charge- densities (J and σ). Consequently, the coupling into the cable may be
simulated by reproducing, through any suitable means, the surface currents and charges on
the screen. Because the cable diameter is assumed to be small, the higher modes may be
neglected and it is possible to use an additional coaxial conductor as the injection structure, as
shown in Figure 2.
L
+
E
U
1n
Z
1n U
1f
Z
1f
Z U
I
Z
2n 2n (1) U
2f
2f
(2) D
Z
Z
IEC  894/10
Key (for Figures 2,3,4,5)
(1), (2) Indicates outer circuit(1), tube, respectively inner circuit(2), cable
Z Characteristic impedance of the outer circuit(1), tube, respectively inner circuit(2), cable

1,2
Dielectric permittivity of the outer circuit(1), tube, respectively inner circuit(2), cable
ε
1,2
β Phase constant of the outer circuit(1), tube, respectively inner circuit(2), cable

1,2
λ Wave length of the outer circuit(1), tube, respectively inner circuit(2), cable

1,2
Coupling length
L
D Diameter of injection cylinder-tube
V Voltmeter
A Ammeter
Z , Z Load resistance at the near end, respectively far end of the outer circuit(1), tube

1n 1f
Z , Z Load resistance at the near end, respectively far end of the inner circuit(2), cable

2n 2f
EMF of the generator
E
I , I Current in the outer circuit(1), tube, respectively inner circuit(2), cable
1 2
U , U Voltage at the near end, respectively far end of the outer circuit(1), tube

1n 1f
Voltage at the near end, respectively far end of the inner circuit(2), cable
U , U
2n 2f
Concept of a triaxial set-up
(1) outer circuit (1), formed by an injection cylinder-tube and the screen under test, with characteristic impedance
Z ,
(2) inner circuit (2), formed by the screen under test, and centre conductor, with characteristic impedance Z ;
screening at the ends of circuit (2) is not shown.
Observe the conditions Z , Z , Z and λ in Figure 3 and Figure 4.
1f 2n 2f
NOTE 1 D << L.
NOTE 2 Both ends of circuit (2) must be well screened.
Figure 2 – Defining and measuring screening parameters – A triaxial set-up

– 10 – TR 62153-4-1 © IEC:2010(E)
4 The intrinsic screening parameters of short cables
4.1 General
The intrinsic parameters refer to an infinitesimal length of cable, like the inductance or
capacitance per unit length of transmission lines. Assuming electrically short cables, with
L << λ which will always apply at low frequencies, the intrinsic screening parameters are
defined and can be measured as indicated in the following subclauses.
4.2 Surface transfer impedance, Z
T
As shown in Figure 3, where Z and Z are zero, the surface transfer impedance (Z in Ω/m)
1f 2f T
is given:
U
2n
Z = (4)
T
I ⋅ L
The dependence of Z on frequency is not simple and is often shown by plotting log Z against
T T
log frequency. Note that the phase of Z may have any value, depending on braid construction
T
and frequency range.
NOTE In circuit (2) of Figure 3, the voltmeter and short circuit can be interchanged.
4.3 Capacitive coupling admittance, Y
C
As shown in Figure 4, where Z and Z are open circuit, the capacitive coupling admittance
1f 2f
(Y in mho/m) is given by:
C
I
Y = j ⋅ω C = (5)
C T
U ⋅ L
1n
where
C is the through capacitance;
T
ω is the radian frequency;
j is the imaginary operator.
The through capacitance C is a real capacitance and has usually a constant value up to
T
1 GHz and higher (with aperture a << λ).
While Z is independent of the characteristics of the coaxial circuits (1) and (2), C is
T T
dependent on those characteristics. There are two ways of overcoming this dependence:
a) The normalized through elastance K (with units of m/F) derived from C is independent of
T T
the size of the outer coaxial circuit (2), but it depends on its permittivity:
K = C /()C ⋅C (6)
T T 1 2
K ~ 1/()ε + ε (7)
T r1 r2
where C and C are the capacitance per unit length of the two coaxial circuits.
1 2
b) The capacitive coupling impedance Z (with units of Ω/m) again derived from C is also
F T
independent of the size of the outer coaxial circuit (2) and, for practical values of ε , is only
r1
slightly dependent on its permittivity:

TR 62153-4-1 © IEC:2010(E) – 11 –
Z = Z Z Y = Z Z jω C (8)
F 1 2 C 1 2 T
()()
Z ~ ε ⋅ ε / ε + ε (9)
F r1 r2 r1 r2
Compared with Z , Z is usually negligible, except for open weave braids. It may, however, be
T F
significant when Z and Z >> Z (audio circuits).
2n 2f 2
Injection cylinder-tube
+
E
circuit (1)
U
1n
Z = 0
1f
Z • L
I T
Shield
circuit (2)
U
T
V
U
2n
Z = 0
2f
∞
Z =
2n
Centre conductor
L << λ
IEC  895/10
Key
See Figure 2.
Figure 3 – Equivalent circuit for the testing of Z
T
Injection cylinder-tube
+
circuit (1)
E
U
1n
Z = ∞
1f
Shield with apertures
circuit (2)
C • L
A T
= 0
Z
2n
Z = ∞
2f
I
ω
Y • L = j C • L
Centre conductor
C T
L λ IEC  896/10
<<
Key
See Figure 2.
Figure 4 – Equivalent circuit for the testing of Y = j ωC
c T
– 12 – TR 62153-4-1 © IEC:2010(E)
Z U
+
U U (x) U
E Z , β Z circuit (1)
1 1n 1 1f 1
1 1
Z
T
I (x)
C
T
Z circuit (2)
Z
2 U (x) U 2
Z , β
2n 2 2 2 2f
x
L
U L: arbitrary U
2n 2f
IEC  897/10
Key
See Figure 2.
NOTE Z and C are distributed (not correctly shown here). The loads Z , Z at the ends may represent matched
T T 1 2
receivers.
Figure 5 – Electrical quantities in a set-up that is matched at both ends
4.4 Injecting with arbitrary cross-sections
A coaxial outer circuit (2) has been assumed so far in this report, but it is not essential because
of the invariance of Z and Z . Using a wire in place of the outer cylinder, the injection
T F
circuit (2) becomes two-wire with the return via the screen of the cable under test. Obviously
the charge and current distribution become non-uniform, but the results are equivalent to
coaxial injection, especially if two injection lines are used opposite to each other, and may be
justified for worst-case testing. Note that the IEC line injection test uses a wire.
4.5 Reciprocity and symmetry
Assuming linear shield materials, the measured Z and Z values will not change when
T F
interchanging the injection circuit (1) and the measuring circuit (2). Each of the two conductors
of the two-line circuit can be interchanged, but in practice the set-up will have to take into
account possible ground loops and coupling to the environment.
4.6 Arbitrary load conditions
When the circuit ends of Figure 3 and Figure 4 are not ideally a short or open circuit, Z and Z
T F
will act simultaneously. Their superposition is noticeable in the low frequency coupling of the
matched circuit (1) and circuit (2), (Figure 5 and Table 1).
5 Long cables – coupled transmission lines
The coupling over the whole length of the cable is obtained by summing up (integrating) the
infinitesimal coupling contributions along the cable while observing the correct phase. The
analysis utilizes the following assumptions and conventions:
– matched circuits considered with the voltage waves U , U , U , see Figure 5,
1 2n 2f
– representation of the coupling, using the normalized wave amplitudes UZ Watt ,
[]
instead of voltage waves. i.e. the coupling transfer function, in the following denoted by
"coupling function", will be defined as
U / Z
2n
T = (10)
n
U / Z
1 1
TR 62153-4-1 © IEC:2010(E) – 13 –
U / Z
2f
T = (11)
f
U / Z
1 1
NOTE 1 T is the ratio of the power waves travelling in circuits (2) and (1). Due to reciprocity and assuming
linear screen (shield) materials, T is reciprocal, i.e. invariant with respect to the interchange of injection and
measuring circuits (1) and (2).
NOTE 2 The quantity 1/T , or in logarithmic quantities
a = –20 × log T (12)
s 10
may be considered as the "screening attenuation" of the cable, specific to the set-up.
Performing the straight forward calculations of coupled transmission line theory, the coupling
function T, given in Table 1, is obtained. The term S{}L ⋅f is the "summing function" S, being
dependent on L and f. (The wavy bracket just indicates that the product L ⋅ f is the argument of
the function S and not a factor to S). S represents the phase effect, when summing up the
infinitesimal couplings along the line, and is:
β L ±
sin
⎛ β L +⎞
S{}L ⋅ f = exp – j ⋅ (13)
⎜ ⎟
n
β L ±
⎝ ⎠
f
with
β L ± =()β ± β ⋅ L (14)
2 1
= 2πLf ⋅()1/ν ±1/ν (15)
2 1
= 2πLf ⋅ ( ε ± ε )/ c (16)
r2 r1
subscript ± refers to near/far end respectively;
+ refers to both near/far ends.
Note that weak coupling, i.e. T << 1, has been assumed. This case, including losses, is given
)
in [1] .
Equation (17) and the representation in Table 1 illustrate the contributions of the different
parameters to the coupling function T:
1 L
T =()Z ± Z ⋅ ⋅ ⋅S{}L ⋅ f,ε ,ε (17)
n F T n r1 r2
Z ⋅ Z
1 2
f f
Note especially the following points.
a) There may be a directional effect (T ≠ T ) in the whole frequency range if Z is not
n f F
negligible. (But Z is usually negligible except with loose, single braid shields.)
F
b) Up to a constant factor, T is the quantity directly measured in a set-up.
___________
)
Figures in square brackets refer to the bibliography.

– 14 – TR 62153-4-1 © IEC:2010(E)
c) For low frequencies, i.e. for short cables (L << λ), the trivial coupling formula is obtained
that is directly proportional to :
L
1 L
T =()Z ± Z ⋅ ⋅ (18)
n F T
Z 2
f
where
Z = Z ⋅ Z
12 1 2
d) The summing function S{}L ⋅ f is presented in Figure 6.
e) S{}L ⋅ f has a sin(x)/x behaviour. A cut-off point may be defined as ()L ⋅ f :
c
c
()L ⋅ f = (19)
c
n
π ε ± ε
r1 r2
f
f) The exact envelope of S{}L ⋅ f is
Env S{}L ⋅ f = (20)
n
()L ⋅ f
f
1+
()L ⋅ f
cn
f
TR 62153-4-1 © IEC:2010(E) – 15 –
a
Table 1 – The coupling transfer function T (coupling function)
b
Set-up parameters
(Z ), L, ε
r1
/\
--------------------- -----------------------
/ \
1 L
T =()Z ± Z ⋅ ⋅ ⋅S{}L⋅f,ε ,ε
n F T n r1 r2
Z ⋅Z
1 2
f f
\ / \ /
----- -------- ----------------- -----------------
\/ \/
b
Intrinsic Cable parameters
screen parameters (Z ,L), ε
r2
\ / \ /
---------------- ----------------- ----------- ------------
\/ \/
"Low-frequency coupling", "HF-effect",
c
short cables cut-off ()L⋅f .
c
\ /
-------------- ---------------
\/
Length + frequency effect
a
T is the power coupling from circuit (1) to circuit (2).
n
The stacked subscripts are associated to the stacked operation symbols ± in
f
the obvious way: upper subscript → upper operation, lower subscript → lower
operation.
b
ε and ε contained in S as parameters.
r1 r2
c
for L<< λ : S{}L⋅f →1 .
g) The first minimum (zero) of S{}L ⋅ f occurs at
()L ⋅f = π(L ⋅f) (21)
min c
()L ⋅ f is S{}L ⋅ f ≈ 1 and
h) As seen from Equations (13) and (20), below the cut-off points
cn
f
above them it starts to oscillate and its envelope drops asymptotically 20 dB/decade,
⎛ ⎞
⎜ ⎟
()
⎜ L ⋅ f ⎟
cn
⎜ ⎟
f
⎝ ⎠
Env S{}L ⋅ f ≈ (22)
n
()L ⋅ f
f
i) S is symmetrical in L and f, i.e. L and f are interchangeable. For a fixed length a cut-off

frequency f and vice versa, for a fixed frequency a cut-off length L may be defined.
c c
Substituting c/λ for f, we obtain the cut-off length as
o
– 16 – TR 62153-4-1 © IEC:2010(E)
λ
o
L = (23)
c
n
π ε ± ε
r1 r2
f
j) The effect of S in the frequency range ( = constant) is illustrated in Figure 8. The coupling
L
function is proportional to Z , only if f < f . Note also the typical values indicated for f .
T c c
k) The minima and maxima of S are not resonances, they are due to cancelling and additive
effects of the coupling along the line.
l) The far end cut-off frequency is significantly influenced by the permittivity of the outer
system (ε ). Selecting ε → ε we obtain ()L ⋅ f → ∞ , i.e. no cut-off at the far end. Due to
r1 r2
r1 cf
practical aspects (tolerances, homogeneity, etc.), an ideal phase matching()ε ≡ ε is not
r1 r2
feasible.
m) The effects of Z and Z on the coupling transfer functions T and T are shown in Figure 8.
T F n f
n) The total effect of L on the coupling is not contained in S alone, but in the product
L ⋅S{}L ⋅ f . The product L ⋅S is presented in Figure 12 for f = constant. The coupling

function T which can be measured in a set-up, is proportional to L if L < L . However, for
c
appropriately long cables (L > L ), the maximum coupling is independent of L and we obtain
c
()
a length independent shielding attenuation above the cut-off point L ⋅ f . But we should
c
()
remember that L ⋅ f as well as A are still dependent on the set-up parameters ()ε ,Z .
r1 1
c s
S
Log scale
S S
n f
log ()L⋅f
()L⋅f    ()L⋅f
()L⋅f 10
cn
cn cf
min, n
IEC  898/10
NOTE S > S above near end cut-off, yielding a directive effect.
f n
()L⋅f : cut-off point
c
Figure 6 – The summing function S{L·f} for near and far end coupling

TR 62153-4-1 © IEC:2010(E) – 17 –
log Z
10 T
(slope is 20dBper decade)
log ()f
f
IEC  899/10
Z (f =10 MHz)= 20 mΩ / m
T 1
Figure 7 – Transfer impedance of a typical single braid screen
Figure 8 gives the result of adding (on a log scale) the frequency responses from Figure 6 and
Figure 7. It is assumed the cable has negligible Z (Z < F F T
log T
L 1
Z ⋅ ⋅
T
2 Z
Env (T )
f
T
f
Env (T )
n
T
n
log ()f
f
f 10
f
cn
r cf
IEC  900/10
Example: ε = 1 (set-up), ε = 2.2 (cable)
r1 r2
L = 1 m;  f = 40 MHz; f = 200 MHz
cn cf
Figure 8 – The effect of the summing function-coupling transfer function of a typical
single braid screen cable
– 18 – TR 62153-4-1 © IEC:2010(E)
-40
T [dB]
T
f
-60 T
fztdBk
T
n
-80
T
nztdBk
5 6 7 8 9 10
1⋅10 1⋅10 1⋅10 1⋅10
1⋅10 1⋅10
f
k f [Hz]
IEC  901/10
In calculations the following parameters are used:
Z (d.c.) =15 mΩ/m and Z (10 MHz) = 20 mΩ/m increasing 20 dB/decade (see Figure 7), cable length 1 m, and
T T
velocities of the outer and inner line: v = 200 Mm/s and v = 280 Mm/s corresponding to a velocity difference of
1 2
40 %.
Figure 9 – Calculated coupling transfer functions
T and T for a single braid – Z = 0
n f F
-40
T [dB]
T
fztdBk
T
f
T
fdBk
-60
T
n
T
ndBk
-80
T
nztdBk
5 6 7 8 9
1⋅10 1⋅10 1⋅10 1⋅10 1⋅10 1⋅10
f [Hz]
f
k
IEC  902/10
T is 3,5 dB higher and T is 6 dB lower than in reference Figure 9 because
n f
T ∼⎪Z + Z = 1,5 × Z and
n F T ⎪ T
T ∼⎪Z – Z = 0,5 × Z
f F T ⎪ T
Figure 10 – Calculated coupling transfer functions T and T for a single braid –
n f
Im(Z ) is positive and Z = +0,5 × Im (Z ) at high frequencies
T F T
TR 62153-4-1 © IEC:2010(E) – 19 –

-40
T [dB]
T
f
T
fdBk
T
fztdBk
-60
T
nztdBk
T
ndBk
T
n
-80
5 7 8 9 10
1⋅10 1⋅10 1⋅10 1⋅10 1⋅10 1⋅10
f
k
f [Hz]
IEC  903/10
T is 3,5 dB higher and T is 6 dB lower than in reference Figure 9 because
f n
T ∼⎪Z – Z ⎪= 1,5 × ⎪Z ⎪ and
f F T T
T ∼⎪Z + Z ⎪= 0,5 × ⎪Z ⎪
n F T T
Figure 11 – Calculated coupling transfer functions T and T for a single braid –
n f
Im(Z ) is negative and Z = –0,5 × Im(Z ) at high frequencies
T F T
In Figure 9, Z = 0 and Z is positive.
F T
In Figure 10 and 11, Z is significant ( Z =()1 2 ×Z ).
F F T
In Figure 11, Z is negative at high frequencies.
T
The following notes apply to Figures 9, 10, and 11.
NOTE 1 T for near-end, T for far-end and dB means that T are calculated in dB ( 20 × log | T | )
n f n,f n,f
NOTE 2 T dB: near-end when Z = 1 2 ×Z and T dB: near-end when Z = 0.
()
n nzt F
F T
NOTE 3 T dB: far-end when Z = 1 2 ×Z and T dB: far-end when Z = 0.
()
f fzt F
F T
– 20 – TR 62153-4-1 © IEC:2010(E)

log L ⋅S
Env()L⋅S
f
f
Env()L⋅S
n
n
f = constant
log ()f
L L
Cn 10
C f
IEC  904/10
NOTE 1 For L > L , the maximum value of T is attained, i.e. the maximum coupling
c
(or the screening attenuation) is not dependent on L.
NOTE 2 L strongly depends on ε .
cf r1
NOTE 3 See also Table 1 and list item n)
Figure 12 – : the complete length dependent factor in the coupling function T
L·S
6 Transfer impedance of a braided wire outer conductor or screen
Typical transfer impedances of cables with braided wire screens are shown in Figure 13.
The constant Z value at the low-frequency e
...