ISO 11451-5:2023
(Main)Road vehicles — Vehicle test methods for electrical disturbances from narrowband radiated electromagnetic energy — Part 5: Reverberation chamber
Road vehicles — Vehicle test methods for electrical disturbances from narrowband radiated electromagnetic energy — Part 5: Reverberation chamber
This document specifies methods for testing the immunity of passenger cars and commercial vehicles to electromagnetic disturbances, regardless of the vehicle propulsion system (e.g. spark ignition engine, diesel engine, electric motor) using a reverberation chamber. The electromagnetic disturbances considered are limited to narrowband electromagnetic fields. While this document refers specifically to passenger cars and commercial vehicles, generalized as “vehicle(s)”, it can readily be applied to other types of vehicles. ISO 11451-1 specifies general test conditions, definitions, practical use, and basic principles of the test procedure. Function performance status classification guidelines for immunity to electromagnetic radiation from an off-vehicle radiation source are given in Annex A.
Véhicules routiers — Méthodes d'essai d'un véhicule soumis à des perturbations électriques par rayonnement d'énergie électromagnétique en bande étroite — Partie 5: Chambre réverbérante
General Information
Buy Standard
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 11451-5
First edition
2023-05
Road vehicles — Vehicle test methods
for electrical disturbances from
narrowband radiated electromagnetic
energy —
Part 5:
Reverberation chamber
Véhicules routiers — Méthodes d'essai d'un véhicule soumis
à des perturbations électriques par rayonnement d'énergie
électromagnétique en bande étroite —
Partie 5: Chambre réverbérante
Reference number
ISO 11451-5:2023(E)
© ISO 2023
---------------------- Page: 1 ----------------------
ISO 11451-5:2023(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
© ISO 2023 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 11451-5:2023(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test conditions .6
5 Test location . 6
5.1 Reverberation chamber description . 6
5.2 Working volume . 7
6 Test instrumentation .7
6.1 General . 7
6.2 Field generating device . 8
6.3 Field probes . 8
6.4 Stimulation and monitoring of the device under test (DUT) . 8
6.5 Optional: receiving antenna(s) and spectrum analyser . 8
6.6 Optional: vector network analyser . 9
7 Test set-up . 9
7.1 Vehicle placement . . 10
7.2 Field generating device location – Antenna constraints . 10
7.3 Vehicle test configurations . 10
7.3.1 Vehicle not connected to the power grid . 10
7.3.2 Vehicle in charging mode 1 or mode 2 (AC powered, without
communication) . 10
7.3.3 Vehicle in charging mode 3 or mode 4 (AC or DC powered, with
communication) . 13
7.3.4 Vehicle in charging mode through wireless power transmission (WPT) . 17
8 Test procedure .19
8.1 General . 19
8.2 Stirring configurations .20
8.3 Test plan . 20
8.4 Test methods . 20
8.5 Reverb method with substitution method power control . 23
8.5.1 Reverb reference points .23
8.5.2 Substitution method with empty chamber calibration .25
8.5.3 Substitution method with calibration including the vehicle .29
8.6 Test report . 31
Annex A (informative) Function performance status classification .32
Annex B (normative) Test level definition .33
Annex C (normative) Reverberation chamber characteristics .36
Annex D (informative) Tuned mode and stirred mode . 44
Annex E (informative) TLS method .48
Annex F (informative) Cavity mode method .55
Annex G (informative) Reverb method with closed-loop power control .59
Annex H (informative) Chamber time constant method .61
Annex I (informative) VNA method .67
Annex J (informative) Measurement of total antenna efficiency η .74
Annex K (informative) Measurement of diffuse field correction factor F .77
df
iii
© ISO 2023 – All rights reserved
---------------------- Page: 3 ----------------------
ISO 11451-5:2023(E)
Annex L (informative) Measurement of τ, Q, and ACS .80
Annex M (normative) Additional AAN(s) .85
Bibliography .86
iv
© ISO 2023 – All rights reserved
---------------------- Page: 4 ----------------------
ISO 11451-5:2023(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 32,
Electrical and electronic components and general system aspects.
A list of all parts in the ISO 11451 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
© ISO 2023 – All rights reserved
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 11451-5:2023(E)
Road vehicles — Vehicle test methods for electrical
disturbances from narrowband radiated electromagnetic
energy —
Part 5:
Reverberation chamber
1 Scope
This document specifies methods for testing the immunity of passenger cars and commercial vehicles
to electromagnetic disturbances, regardless of the vehicle propulsion system (e.g. spark ignition engine,
diesel engine, electric motor) using a reverberation chamber.
The electromagnetic disturbances considered are limited to narrowband electromagnetic fields.
While this document refers specifically to passenger cars and commercial vehicles, generalized as
“vehicle(s)”, it can readily be applied to other types of vehicles.
ISO 11451-1 specifies general test conditions, definitions, practical use, and basic principles of the test
procedure.
Function performance status classification guidelines for immunity to electromagnetic radiation from
an off-vehicle radiation source are given in Annex A.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 11451-1:2015, Road vehicles — Vehicle test methods for electrical disturbances from narrowband
radiated electromagnetic energy — Part 1: General principles and terminology
IEC 61000-4-21, Electromagnetic compatibility (EMC) – Part 4-21: Testing and measurement techniques –
Reverberation chamber test methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11451-1 and the following
apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
1
© ISO 2023 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 11451-5:2023(E)
3.1
mean absorption cross section
ACS
1
Ad==σ σσ+ Ω
()
acsa a,TE a,TM
Ω ∫∫
8π
4π
where
σ
is the absorption cross section for incident waves from a spatial direction averaged over TE
a
and TM waves;
σ
is the absorption cross section for incident TE waves from a spatial direction;
a,TE
σ
is the absorption cross section for incident TM waves from a spatial direction;
a,TM
Ω is the solid angle which is 4π for the full sphere (i.e. waves from all angles).
Note 1 to entry: It is the measure for the ability of a vehicle to absorb energy in a reverberation chamber (3.16). It
gives the cross section area of an equivalent ideal absorber without any reflections or scattering, which absorbs
the same energy as the vehicle in the reverberation chamber. In contrast to the chamber loading factor (CLF)
(3.5), the ACS is a property of the vehicle only and is the same for all reverberation chambers. Therefore, it allows
determination of the necessary extra power to compensate the loading effects by the vehicle without a loading
factor measurement or a new chamber characterization with vehicle.
Note 2 to entry: See Annexes H and L.
Note 3 to entry: See Reference [19].
3.2
antenna characterization factor
ACF
ratio of the average received power to forward power obtained in the antenna characterization of the
empty chamber characterization
Note 1 to entry: See 8.5.2.
3.3
cavity mode method
method adopting chamber modes to generate the required field strength with less power for the
frequency between TLS method (3.22) and the lowest usable frequency (LUF) (3.11), typically (30-
80) MHz, where the chamber has a lower mode density
Note 1 to entry: See Annex F.
3.4
chamber characterization factor
CCF
normalized average received power with the vehicle present
Note 1 to entry: See 8.5.2.
3.5
chamber loading factor
CLF
ratio of the antenna characterization factor (3.2) to the chamber characterization factor (3.4)
Note 1 to entry: See 8.5.2.
Note 2 to entry: It is a measure for the additional loading of the chamber due to the test setup including, for
example, the vehicle and the support equipment (3.21).
2
© ISO 2023 – All rights reserved
---------------------- Page: 7 ----------------------
ISO 11451-5:2023(E)
3.6
chamber time constant
mean time decay of the received power delay profile in a reverberation chamber (3.16)
Note 1 to entry: See Annexes H and L.
3.7
charging mode
mode of operation intended for charging the rechargeable energy storage system (storage system that
provides electric energy for electric propulsion which can be recharged)
3.7.1
charging mode 1
charging mode (3.7) where the vehicle is connected to a standard socket-outlet of an AC supply network,
utilizing a cable and plug, both of which are not fitted with any supplementary pilot or auxiliary contacts
Note 1 to entry: In some countries, mode 1 charging can be prohibited or requires special precautions.
Note 2 to entry: Charging mode 1 is defined in IEC 61851-1:2017,6.2.1.
3.7.2
charging mode 2
charging mode (3.7) where the vehicle is connected to AC mains using a charging cable, which has an
EV supply equipment (EVSE) (3.10) box in-line (e.g. in-cable control box / in-cable control and protection
device), providing control pilot signalling between the vehicle and the EVSE box and personal protection
against electric shock
Note 1 to entry: In some countries, special restrictions are applied for mode 2 charging.
Note 2 to entry: There is no communication with the vehicle.
Note 3 to entry: Charging mode 2 is defined in IEC 61851-1:2017,6.2.2.
3.7.3
charging mode 3
charging mode (3.7) where the vehicle is connected to a fixed installation [EV supply equipment (EVSE)
(3.10), e.g. AC charging station, AC wallbox] providing AC power to the vehicle, with communication
between the vehicle and the EVSE (through signal/control lines and/or through wired network lines)
Note 1 to entry: Charging mode 3 is defined in IEC 61851-1:2017,6.2.3.
3.7.4
charging mode 4
charging mode (3.7) where the vehicle is connected to a fixed installation [EV supply equipment (EVSE)
(3.10), e.g. DC charging station], providing DC power to the vehicle (with an off-board charger), with
communication between the vehicle and the EVSE (through signal/control lines and/or through wired
network lines)
Note 1 to entry: Charging mode 4 is defined in IEC 61851-1:2017,6.2.4.
3.8
coherence time of the reverberation chamber
time interval between two independent stirring configurations (3.19) in stirred mode (3.18)
Note 1 to entry: The field in the reverberation chamber (3.16) conserves its statistical properties [e.g. the positions
of the field maxima and minima in the working volume (3.27)] during the coherence time.
3
© ISO 2023 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 11451-5:2023(E)
3.9
CDF
cumulative distribution function
probability that the electromagnetic field strength is less or equal to a specific value
Note 1 to entry: A value of this function can be used as levelling target (e.g. 100 V/m at CDF 0,2 means 20 % of the
measured electric field strength values are less or equal to 100 V/m and 80 % are higher than 100 V/m).
3.10
EVSE
EV supply equipment
equipment or a combination of equipment, providing dedicated functions to supply electric energy from
a fixed electrical installation or supply network to an EV for the purpose of charging
3.11
lowest usable frequency
LUF
lowest frequency for which the field uniformity requirements are met for the reverb method (3.17) and
at least 12 independent stirring configurations (3.19) can be achieved
Note 1 to entry: The LUF is determined in accordance with C.6.
3.12
maximum chamber loading factor
MLF
figure of merit corresponding to the worst case loading configuration for which the field uniformity has
been demonstrated
Note 1 to entry: See 8.5.2.
3.13
periodization
method to define an analysis time window for the calculation of autocorrelation coefficients based on
the complete period of a periodic stirring process sequence
3.14
power delay profile
PDP
temporal behaviour of the power decay in a reverberation chamber (3.16) after switch-off of the power
source
3.15
quasi-tuned mode
operating mode of a reverberation chamber (3.16) where the response time of the DUT to the external
field is shorter than the coherence time of the reverberation chamber (3.8)
Note 1 to entry: See D.3.1.
3.16
reverberation chamber
high Q shielded room (cavity) whose boundary conditions are changed via one or several rotating
tuners or moving walls (including vibrating intrinsic reverberation chambers (VIRCs) (3.28) with or
without conductive contact to the floor) or repositioning of the transmitting antenna(s)
Note 1 to entry: This results in a statistically uniform electromagnetic field.
3.17
reverb method
usage of a reverberation chamber (3.16) above the lowest usable frequency (LUF) (3.11)
4
© ISO 2023 – All rights reserved
---------------------- Page: 9 ----------------------
ISO 11451-5:2023(E)
3.18
stirred mode
operating mode of a reverberation chamber (3.16) where a tuner (3.25) or a vibrating intrinsic
reverberation chamber (VIRC) (3.28) shaker is moved continuously while the test is running
3.19
stirring configuration
unique set of conditions that defines the RF environment
Note 1 to entry: It can stand for a single tuner (3.25) in a fixed position as in classical reverberation chambers
(3.16). In addition, it can stand for a position of a vibrating intrinsic reverberation chamber (VIRC) (3.28) at a point
in time, for a momentary frequency in case of frequency stirring, or a transmitting antenna configuration.
3.20
stirring scheme
operating mode of a reverberation chamber (3.16) that is a stirred mode (3.18) or a tuned mode (3.24) or
a combination thereof
3.21
support equipment
equipment associated with performing an EMC test on a vehicle including (but not all inclusive) load
simulator, charging cables, AMN(s), HV-AN(s), AAN(s), DUT monitoring equipment including fibre optic
interface modules and TV camera
3.22
TLS method
method using a TLS (similar as in ISO 11451-2) inside a reverberation chamber (3.16) and which
extends the usage beyond TEM-waveguide testing up to the lowest usable frequency (LUF) (3.11) of the
reverberation chamber
Note 1 to entry: See Annex E.
3.23
total antenna efficiency
ratio of radiated power to forward power at antenna port, it is less than 1 or 100 % due to mismatching
and losses of the antenna (e.g. ohmic loss of metallic material and dielectric loss of insulation)
Note 1 to entry: See Annex J.
3.24
tuned mode
operating mode of a reverberation chamber (3.16) where the tuner (3.25) is moved stepwise to fixed
positions and the test is repeated successively at each of those fixed tuner positions
3.25
tuner
large metallic reflector capable of changing the electromagnetic boundary conditions in a reverberation
chamber (3.16) as it rotates or moves
Note 1 to entry: As the tuner moves, the nulls and maximums in the field change location, ensuring the vehicle is
exposed to a statistically uniform field.
3.26
windowing
method to define an analysis time window for the calculation of autocorrelation coefficients based on a
part of a stirring process sequence
3.27
working volume
volume within the reverberation chamber (3.16) that contains the vehicle, the support equipment (3.21),
and the receiving antenna, if used
5
© ISO 2023 – All rights reserved
---------------------- Page: 10 ----------------------
ISO 11451-5:2023(E)
3.28
VIRC
vibrating intrinsic reverberation chamber
tent-like structure formed by conductive fabrics where movements of the walls are excited, e.g. by
moving arms which push and pull corners or edges of the tent
4 Test conditions
The applicable frequency range for the reverb method is LUF to 18 000 MHz. Testing over the full
frequency range could require different field-generating devices, but this does not imply that testing of
overlapping frequency ranges is required.
NOTE The applicable frequency range is 0,01 MHz to LUF for the TLS method (see Annex E), 30 MHz to LUF
for the cavity mode method (see Annex F), and LUF to 18 000 MHz for the other reverb methods (see Annexes G,
H and I).
The user shall specify the test severity level or levels over the frequency range. Suggested test severity
levels are given in Annex A.
Standard test conditions are given in ISO 11451-1 for the following:
— test temperature;
— supply voltage;
— modulation;
— dwell time;
— frequency step sizes;
— definition of test severity levels;
— test signal quality.
5 Test location
5.1 Reverberation chamber description
The test shall be performed in a reverberation chamber.
The aim of using a reverberation chamber is to create statistically homogeneous and isotropic
electromagnetic fields within the working volume.
These conditions are not valid close to the ground floor in the working volume (see 5.2).
A reverberation chamber for vehicle testing consists of a shielded enclosure, one or several field
generating devices, and some mechanical apparatus to change the boundary conditions for the
electromagnetic fields. This mechanical apparatus may, for example, contain one or several rotating
tuners or moving walls, or may even be realized by using conductive fabrics as shielded enclosure (e.g.
a VIRC).
The chamber may contain a vehicle dynamometer, a turntable or both.
It may also contain a TLS (see Annex E) or other type of field generators (e.g. tunable monopoles, see
Annex F) as field generating device for testing from 0,01 MHz to the LUF.
The chamber may also contain one or several receiving antennas and one or more field probes.
The size, shape and construction of the reverberation chamber can vary considerably. The minimum
size of the shielded enclosure is determined by the size of the test region needed, the size of the
6
© ISO 2023 – All rights reserved
---------------------- Page: 11 ----------------------
ISO 11451-5:2023(E)
field generation device or devices, the size and shape and location of the tuner or tuners, the needed
clearances between all these and the largest vehicle to be tested, and the intended LUF of the chamber.
An example of a rectangular reverberation chamber with one mechanical tuner and one field generating
antenna is shown in Figure 1.
After initial construction, the reverberation chamber shall be characterized in accordance with the
test methods intended to be used. For the reverb method, the chamber shall fulfil the field uniformity
requirements of Table C.2. The LUF of the reverberation chamber is determined during this initial
characterization. Following any major modifications, a new chamber characterization shall be carried
out again. Changes to the tuners shall be considered a major modification.
5.2 Working volume
The working volume is the volume that contains the vehicle, any support equipment and the receiving
antenna, if used. The form of the working volume shall be a cuboid.
The minimum distance between the working volume and the walls and ceiling of the shielded enclosure
or any tuner or any transmitting antenna shall be at least λ/4 at the lowest used frequency of the reverb
method.
The working volume for testing vehicles starts directly on the ground plane in order to contain the full
vehicle. Although this differs from the IEC 61000-4-21 working volume definition, for the purpose of
chamber calibration, the reverb reference points described in IEC 61000-4-21 shall be used.
NOTE For the TLS method (see Annex E), and the cavity mode method (see Annex F), the λ/4 minimum
distance requirement does not apply.
More than one vehicle can be tested in one immunity test (e.g. testing of communication between
vehicles). If the distance between the vehicles is closer than λ/4 at the lowest tested frequency there
could be significant interaction between the vehicles. This can be desirable for investigating proximity
effects. If the distance between the vehicles is larger than λ/4 at the lowest tested frequency there
will be scattering between the vehicles similar to the scattering from walls, etc. Therefore, this test
can be interpreted as the simultaneous independent test of multiple vehicles. In either case, the field
homogeneity requirements shall still be fulfilled with multiple vehicles present and the loading shall be
compensated appropriately as defined in the applicable test method.
6 Test instrumentation
6.1 General
Testing consists of generating radiated electromagnetic fields using antenna sets with radio frequency
(RF) sources capable of producing the desired field strength over the range of test frequencies.
The following test instrumentation is used:
— field generating device(s): e.g. antenna(s);
— field probe(s);
— RF signal generator with internal or external modulation capability;
— high power amplifier(s);
— power meter (or equivalent measuring instrument) to measure forward power and reflected power;
— optional: receiving antenna(s) and spectrum analyser;
— optional: vector network analyser.
7
© ISO 2023 – All rights reserved
---------------------- Page: 12 ----------------------
ISO 11451-5:2023
...
DRAFT INTERNATIONAL STANDARD
ISO/DIS 11451-5
ISO/TC 22/SC 32 Secretariat: JISC
Voting begins on: Voting terminates on:
2022-06-24 2022-09-16
Road vehicles — Vehicle test methods for electrical
disturbances from narrowband radiated electromagnetic
energy —
Part 5:
Reverberation chamber
Véhicules routiers — Méthodes d'essai d'un véhicule soumis à des perturbations électriques par
rayonnement d'énergie électromagnétique en bande étroite —
Partie 5: Chambre réverbérante
ICS: 43.040.10; 33.100.20
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
This document is circulated as received from the committee secretariat.
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 11451-5:2022(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022
---------------------- Page: 1 ----------------------
ISO/DIS 11451-5:2022(E)
DRAFT INTERNATIONAL STANDARD
ISO/DIS 11451-5
ISO/TC 22/SC 32 Secretariat: JISC
Voting begins on: Voting terminates on:
Road vehicles — Vehicle test methods for electrical
disturbances from narrowband radiated electromagnetic
energy —
Part 5:
Reverberation chamber
Véhicules routiers — Méthodes d'essai d'un véhicule soumis à des perturbations électriques par
rayonnement d'énergie électromagnétique en bande étroite —
Partie 5: Chambre réverbérante
ICS: 43.040.10; 33.100.20
COPYRIGHT PROTECTED DOCUMENT
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
© ISO 2022
THEREFORE SUBJECT TO CHANGE AND MAY
This document is circulated as received from the committee secretariat.
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
NOT BE REFERRED TO AS AN INTERNATIONAL
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on STANDARD UNTIL PUBLISHED AS SUCH.
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
IN ADDITION TO THEIR EVALUATION AS
or ISO’s member body in the country of the requester. BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
ISO copyright office
USER PURPOSES, DRAFT INTERNATIONAL
CP 401 • Ch. de Blandonnet 8
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
CH-1214 Vernier, Geneva
POTENTIAL TO BECOME STANDARDS TO
Phone: +41 22 749 01 11
WHICH REFERENCE MAY BE MADE IN
Reference number
Email: copyright@iso.org
NATIONAL REGULATIONS.
Website: www.iso.org ISO/DIS 11451-5:2022(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
Published in Switzerland
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
ii
© ISO 2022 – All rights reserved
PROVIDE SUPPORTING DOCUMENTATION. © ISO 2022
---------------------- Page: 2 ----------------------
ISO/DIS 11451-5:2022(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Test conditions .5
5 Test location . 6
5.1 Reverberation chamber description . 6
5.2 Working volume . 6
6 Test instrumentation .7
6.1 Field generating device . 7
6.2 Field probes . 7
6.3 Stimulation and monitoring of the device under test (DUT) . 8
6.4 Optional: receiving antenna(s) and spectrum analyser . 8
6.5 Optional: vector network analyser . 9
7 Test set-up . 9
7.1 Vehicle placement . . 10
7.2 Field generating device location – Antenna constraints . 10
7.3 Vehicle test configurations . 10
7.3.1 Vehicle not connected to the power grid . 10
7.3.2 Vehicle in charging mode 1 or mode 2 (AC powered, without
communication) . 10
7.3.3 Vehicle in charging mode 3 or mode 4 (AC or DC powered, with
communication) . 14
7.3.4 Vehicle in charging mode through wireless power transmission (WPT) . 18
8 Test procedure .20
8.1 General . 20
8.2 Stirring configurations . 21
8.3 Test plan . 21
8.4 Test methods . 22
8.5 Reverb method with substitution method power control . 24
8.5.1 Reverb reference points . 24
8.5.2 Substitution method with empty chamber calibration .26
8.5.3 Substitution method with calibration including the vehicle .30
8.6 Test report . 32
Annex A (informative) Function performance status classification .33
Annex B (normative) Test level definition .34
Annex C (normative) Reverberation chamber characteristics.37
Annex D (informative) Tuned mode and stirred mode .46
Annex E (informative) TLS method .50
Annex F (informative) Cavity mode method .57
Annex G (informative) Reverb method with closed-loop power control .61
Annex H (informative) Chamber time constant method .63
Annex I (informative) VNA method .69
Annex J (informative) Measurement of total antenna efficiency η .76
Annex K (informative) Measurement of diffuse field correction factor F .79
df
iii
© ISO 2022 – All rights reserved
---------------------- Page: 3 ----------------------
ISO/DIS 11451-5:2022(E)
Annex L (informative) Measurement of τ, Q, and ACS .82
Annex M (normative) Additional AAN(s) . .87
Bibliography .89
iv
© ISO 2022 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/DIS 11451-5:2022(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 32,
Electrical and electronic components and general system aspects.
A list of all parts in the ISO 11451 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
© ISO 2022 – All rights reserved
---------------------- Page: 5 ----------------------
DRAFT INTERNATIONAL STANDARD ISO/DIS 11451-5:2022(E)
Road vehicles — Vehicle test methods for electrical
disturbances from narrowband radiated electromagnetic
energy —
Part 5:
Reverberation chamber
1 Scope
This part of ISO 11451 specifies methods for testing the immunity of passenger cars and commercial
vehicles to electromagnetic disturbances, regardless of the vehicle propulsion system (e.g. spark
ignition engine, diesel engine, electric motor) using a reverberation chamber.
The electromagnetic disturbances considered are limited to narrowband electromagnetic fields.
While this standard refers specifically to passenger cars and commercial vehicles, generalized as
“vehicle(s)”, it can readily be applied to other types of vehicles.
ISO 11451-1 specifies general test conditions, definitions, practical use, and basic principles of the test
procedure.
Function performance status classification guidelines for immunity to electromagnetic radiation from
an off-vehicle radiation source are given in Annex A.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 11451-1, Road vehicles — Vehicle test methods for electrical disturbances from narrowband radiated
electromagnetic energy — Part 1: General principles and terminology
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11451-1 and the following
apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
(mean) absorption cross section
ACS
[17]
average absorption cross section averaged over all polarizations and incident angles
1
Ad==σ σσ+ Ω (1)
()
acsa a,TE a,TM
Ω ∫∫
8π
4π
where
1
© ISO 2022 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/DIS 11451-5:2022(E)
σ
is the absorption cross section for incident waves from a spatial direction averaged over
a
TE and TM waves,
σ
is the absorption cross section for incident TE waves from a spatial direction,
a,TE
σ
is the absorption cross section for incident TM waves from a spatial direction,
a,TM
Ω is the solid angle which is 4π for the full sphere (i.e. waves from all angles).
Note 1 to entry: measure for the ability of a vehicle to absorb energy in a reverberation chamber. It gives the
cross section area of an equivalent ideal absorber without any reflections or scattering, which absorbs the same
energy as the vehicle in the reverberation chamber. In contrast to the CLF, the ACS is a property of the vehicle
only and is the same for all reverberation chambers. Therefore, it allows determination of the necessary extra
power to compensate the loading effects by the vehicle without a loading factor measurement or a new chamber
characterization with vehicle.
Note 2 to entry: see Annexes H and L
3.2
antenna characterization factor
ACF
ratio of the average received power to forward power obtained in the antenna characterization of the
empty chamber characterization
Note 1 to entry: see 8.5.2
3.3
cavity mode method
method adopting chamber modes to generate the required field strength with less power for the
frequency between TLS method and LUF, typically 30-80 MHz, where the chamber has a lower mode
density
Note 1 to entry: see Annex F
3.4
chamber characterization factor
CCF
normalized average received power with the vehicle present
Note 1 to entry: see 8.5.2
3.5
chamber loading factor
CLF
ratio of the antenna characterization factor to the chamber characterization factor
Note 1 to entry: see 8.5.2
Note 2 to entry: it is a measure for the additional loading of the chamber due to the test setup including, for
example, the vehicle and the support equipment
3.6
chamber time constant
the mean time decay of the received power delay profile in a reverberation chamber
Note 1 to entry: see Annexes H and L
3.7
charging mode
mode of operation intended for charging the Rechargeable Energy Storage System (REESS)
2
© ISO 2022 – All rights reserved
---------------------- Page: 7 ----------------------
ISO/DIS 11451-5:2022(E)
3.7.1
charging mode 1
charging mode as defined in 6.2.1 of IEC 61851-1:2017
Note 1 to entry: in some countries, mode 1 charging can be prohibited or requires special precautions
3.7.2
charging mode 2
charging mode as defined in 6.2.2 of IEC 61851-1:2017, where the vehicle is connected to AC mains
using a charging cable, which has an Electric Vehicle Supply Equipment (EVSE) box in-line (e.g. In-Cable
Control Box / In-Cable Control and Protection Device), providing control pilot signalling between the
vehicle and the EVSE box and personal protection against electric shock
Note 1 to entry: in some countries, special restrictions have to be applied for mode 2 charging
Note 2 to entry: there is no communication with the vehicle
3.7.3
charging mode 3
charging mode as defined in 6.2.3 of IEC 61851-1:2017, where the vehicle is connected to a fixed
installation (EVSE, e.g. AC charging station, AC wallbox) providing AC power to the vehicle, with
communication between the vehicle and the EVSE (through signal/control lines and/or through wired
network lines)
3.7.4
charging mode 4
charging mode as defined in 6.2.4 of IEC 61851-1:2017, where the vehicle is connected to a fixed
installation (EVSE, e.g. DC charging station), providing DC power to the vehicle (with an off-board
charger), with communication between the vehicle and the EVSE (through signal/control lines and/or
through wired network lines)
3.8
coherence time of the reverberation chamber
time interval between two independent stirring configurations in stirred mode. The field in the
reverberation chamber conserves its statistical properties (e.g. the positions of the field maxima and
minima in the working volume) during the coherence time.
3.9
cumulative distribution function
CDF
probability that the electromagnetic field strength is less or equal to a specific value. A value of this
function can be used as levelling target (e.g. 100 V/m at CDF 0,2 means 20 % of the measured electric
field strength values are less or equal to 100 V/m and 80 % are higher than 100 V/m).
3.10
EV supply equipment
EVSE
equipment or a combination of equipment, providing dedicated functions to supply electric energy from
a fixed electrical installation or supply network to an EV for the purpose of charging
3.11
lowest usable frequency
LUF
lowest frequency for which the field uniformity requirements are met for the reverb method and at
least 12 independent stirring configurations can be achieved
Note 1 to entry: the LUF is determined in accordance with C.6 in Annex C
3
© ISO 2022 – All rights reserved
---------------------- Page: 8 ----------------------
ISO/DIS 11451-5:2022(E)
3.12
maximum chamber loading factor
MLF
maximum chamber loading factor for which the field uniformity has been demonstrated
Note 1 to entry: see 8.5.2
3.13
periodization
a method to define an analysis time window for the calculation of autocorrelation coefficients based on
the complete period of a periodic stirring process sequence
3.14
power delay profile
PDP
temporal behaviour of the power decay in a reverberation chamber after switch-off of the power source
3.15
quasi-tuned mode
an operating mode of a reverberation chamber where the response time of the DUT to the external field
is shorter than the coherence time of the reverberation chamber
3.16
rechargeable energy storage system
RESS
storage system that provides electric energy for electric propulsion which can be recharged
Note 1 to entry: components of the REESS may be high voltage (HV) batteries
3.17
reverberation chamber
high Q shielded room (cavity) whose boundary conditions are changed via one or several rotating tuners
or moving walls (including VIRCs with or without conductive contact to the floor) or repositioning of
the transmitting antenna(s)
Note 1 to entry: this results in a statistically uniform electromagnetic field
3.18
reverb method
usage of a reverberation chamber above LUF
3.19
stirred mode
an operating mode of a reverberation chamber where a tuner or a VIRC shaker is moved continuously
while the test is running
3.20
stirring configuration
a unique set of conditions that defines the RF environment. It might stand for a single tuner in a fixed
position as in classical reverberation chambers, it might stand for a position of a VIRC at a point in time,
for a momentary frequency in case of frequency stirring, or a transmitting antenna configuration.
3.21
stirring scheme
operating mode of a reverberation chamber that is a stirred mode or a tuned mode or a combination
thereof
4
© ISO 2022 – All rights reserved
---------------------- Page: 9 ----------------------
ISO/DIS 11451-5:2022(E)
3.22
support equipment
equipment associated with performing an EMC test on a vehicle including (but not all inclusive) load
simulator, charging cables, AMN(s), HV-AN(s), AAN(s), DUT monitoring equipment including fibre optic
interface modules and TV camera
3.23
TLS method
method using a TLS (similar as in ISO 11451-2) inside a reverberation chamber and extends the usage
beyond TEM-waveguide testing up to the LUF of the reverberation chamber
Note 1 to entry: see Annex E
3.24
total antenna efficiency
ratio of radiated power to forward power at antenna port, it is less than 1 or 100 % due to mismatching
and losses of the antenna (e.g. ohmic loss of metallic material and dielectric loss of insulation)
Note 1 to entry: see Annex J
3.25
tuned mode
operating mode of a reverberation chamber where the tuner is moved stepwise to fixed positions and
the test is repeated successively at each of those fixed tuner positions
3.26
tuner
large metallic reflector capable of changing the electromagnetic boundary conditions in a reverberation
chamber as it rotates or moves
Note 1 to entry: as the tuner moves, the nulls and maximums in the field change location, ensuring the vehicle is
exposed to a statistically uniform field
3.27
windowing
method to define an analysis time window for the calculation of autocorrelation coefficients based on a
part of a stirring process sequence
3.28
working volume
volume within the reverberation chamber that contains the vehicle, the support equipment, and the
receiving antenna, if used
3.29
VIRC
vibrating intrinsic reverberation chamber (a tent-like structure formed by conductive fabrics where
movements of the walls are excited e.g. by moving arms which push and pull corners or edges of the
tent)
4 Test conditions
The applicable frequency range for the reverb method is LUF to 18 000 MHz. Testing over the full
frequency range could require different field-generating devices, but this does not imply that testing of
overlapping frequency ranges is required.
NOTE The applicable frequency range is 0,01 MHz to LUF for the TLS method (see Annex E), 30 MHz to LUF
for the cavity mode method (see Annex F), and LUF to 18 000 MHz for the other reverb methods (see Annexes G,
H and I).
The user shall specify the test severity level or levels over the frequency range. Suggested test severity
levels are given in Annex A of this International Standard.
5
© ISO 2022 – All rights reserved
---------------------- Page: 10 ----------------------
ISO/DIS 11451-5:2022(E)
Standard test conditions are given in ISO 11451-1 for the following:
— test temperature;
— supply voltage;
— modulation;
— dwell time;
— frequency step sizes;
— definition of test severity levels;
— test signal quality.
5 Test location
5.1 Reverberation chamber description
The test shall be performed in a reverberation chamber.
The aim of using a reverberation chamber is to create statistically homogeneous and isotropic
electromagnetic fields within the working volume.
These conditions are not valid close to the ground floor in the working volume (see 5.2).
A reverberation chamber for vehicle testing consists of a shielded enclosure, one or several field
generating devices, and some mechanical apparatus to change the boundary conditions for the
electromagnetic fields. This mechanical apparatus may for example contain one or several rotating
tuners or moving walls, or may even be realized by using conductive fabrics as shielded enclosure (e.g.
a VIRC).
The chamber may contain a vehicle dynamometer, a turntable or both.
It may also contain a TLS (see Annex E) or other type of field generators (e.g. tunable monopoles, see
Annex F) as field generating device for testing from 0,01 MHz to the LUF.
The chamber may also contain one or several receiving antennas and one or more field probes.
The size, shape, and construction of the reverberation chamber can vary considerably. The minimum
size of the shielded enclosure is determined by the size of the test region needed, the size of the
field generation device or devices, the size and shape and location of the tuner or tuners, the needed
clearances between all these and the largest vehicle to be tested, and the intended LUF of the chamber.
An example of a rectangular reverberation chamber with one mechanical tuner and one field generating
antenna is shown in Figure 1.
After initial construction, the reverberation chamber shall be characterized in accordance with the
test methods intended to be used. For the reverb method, the chamber shall fulfil the field uniformity
requirements of Table C.2. The LUF of the reverberation chamber is determined during this initial
characterization. Following any major modifications, a new chamber characterization shall be carried
out again. Changes to the tuners shall be considered a major modification.
5.2 Working volume
The working volume is the volume that contains the vehicle, any support equipment and the receiving
antenna, if used. The form of the working volume shall be a cuboid.
The minimum distance between the working volume and the walls and ceiling of the shielded enclosure
or any tuner or any transmitting antenna shall be at least λ/4 at the lowest used frequency of the reverb
method.
6
© ISO 2022 – All rights reserved
---------------------- Page: 11 ----------------------
ISO/DIS 11451-5:2022(E)
The working volume for testing vehicles starts directly on the ground plane in order to contain the
full vehicle. Although this differs from IEC 61000-4-21 working volume definition, for the purpose of
chamber calibration, the reverb reference points described in IEC 61000-4-21 shall be used.
NOTE 1 For TLS method (see Annex E), and cavity mode method (see Annex F), the λ/4 minimum distance
requirement does not apply.
NOTE 2 More than one vehicle can be tested in one immunity test (e.g. testing of communication between
vehicles). If the distance between the vehicles is closer than λ/4 at the lowest tested frequency there could be
significant interaction between the vehicles. This may be desirable for investigating proximity effects. If the
distance between the vehicles is larger than λ/4 at the lowest tested frequency there will be scattering between
the vehicles similar to the scattering from walls etc. Therefore this test
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.