Road vehicles — Vehicle test methods for electrical disturbances from narrowband radiated electromagnetic energy — Part 4: Harness excitation methods

This document specifies harness excitation methods for testing the electromagnetic immunity of electronic components for passenger cars and commercial vehicles regardless of the propulsion system (e.g. spark-ignition engine, diesel engine, electric motor). The bulk current injection (BCI) test method is based on current injection into the wiring harness using a current probe as a transformer where the harness forms the secondary winding. The tubular wave coupler (TWC) test method is based on a wave coupling into the wiring harness using the directional coupler principle. The TWC test method was developed for immunity testing of automotive components with respect to radiated disturbances in the GHz ranges (GSM bands, UMTS, ISM 2,4 GHz). It is best suited to small (with respect to wavelength) and shielded device under test (DUT), since in these cases the dominating coupling mechanism is via the harness. The electromagnetic disturbance considered in this document is limited to continuous narrowband electromagnetic fields. ISO 11451-1 gives definitions, practical use and basic principles of the test methods.

Véhicules routiers — Méthodes d'essai d'un véhicule soumis à des perturbations électriques par rayonnement d'énergie électromagnétique en bande étroite — Partie 4: Méthodes d'excitation des faisceaux

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INTERNATIONAL ISO
STANDARD 11451-4
Fourth edition
2022-05
Road vehicles — Vehicle test methods
for electrical disturbances from
narrowband radiated electromagnetic
energy —
Part 4:
Harness excitation methods
Véhicules routiers — Méthodes d'essai d'un véhicule soumis
à des perturbations électriques par rayonnement d'énergie
électromagnétique en bande étroite —
Partie 4: Méthodes d'excitation des faisceaux
Reference number
ISO 11451-4:2022(E)
© ISO 2022
---------------------- Page: 1 ----------------------
ISO 11451-4:2022(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

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
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Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2022 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 11451-4:2022(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 1

4 Test conditions .......................................................................................................................................................................................................1

5 Test location .............................................................................................................................................................................................................. 2

6 Test instrumentation ......................................................................................................................................................................................2

6.1 BCI test method...................................................................................................................................................................................... 2

6.1.1 General ........................................................................................................................................................................................ 2

6.1.2 Injection probe ..................................................................................................................................................................... 3

6.1.3 Current measurement probe ................................................................................................................................... 3

6.1.4 Stimulation and monitoring of the DUT ........................................................................................................ 3

6.2 TWC test method .................................................................................................................................................................................. 3

6.2.1 General ........................................................................................................................................................................................ 3

6.2.2 Tubular wave coupler ..................................................................................................................................................... 4

6.2.3 50 Ω load resistor ................................... ........................................................................................................ .................... 4

6.2.4 Stimulation and monitoring of the DUT ........................................................................................................ 4

7 Test set-up ................................................................................................................................................................................................................... 4

7.1 BCI Test methods .................................................................................................................................................................................. 4

7.1.1 Substitution method ....................................................................................................................................................... 4

7.1.2 Closed-loop method with power limitation ............................................................................................... 5

7.2 TWC Test methods .............................................................................................................................................................................. 6

8 Test procedure .......................................................................................................................................................................................................7

8.1 General ........................................................................................................................................................................................................... 7

8.2 Test plan ....................................................................................................................................................................................................... 7

8.3 Test methods ............................................................................................................................................................................................ 8

8.3.1 BCI test method ................................................................................................................................................................... 8

8.3.2 Tubular wave coupler test method .................................................................................................................. 10

8.4 Test report ............................................................................................................................................................................................... 11

Annex A (normative) Calibration configuration (current injection probe calibration) ............................13

Annex B (informative) Test set-up transfer impedance ...............................................................................................................15

Annex C (informative) Function performance status classification (FPSC) ...........................................................22

iii
© ISO 2022 – All rights reserved
---------------------- Page: 3 ----------------------
ISO 11451-4:2022(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. 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. www.iso.org/patents

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.

This fourth edition cancels and replaces the third edition (ISO 11451-4:2013), which has been

technically revised.
The main changes are as follows:
— extension of BCI frequency range,
— addition of TWC test method,
— update of test plan and test report requirements,
— update of Annexes A, B and C for consistency with ISO 11452-4:2020.
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.
© ISO 2022 – All rights reserved
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 11451-4:2022(E)
Road vehicles — Vehicle test methods for electrical
disturbances from narrowband radiated electromagnetic
energy —
Part 4:
Harness excitation methods
1 Scope

This document specifies harness excitation methods for testing the electromagnetic immunity of

electronic components for passenger cars and commercial vehicles regardless of the propulsion system

(e.g. spark-ignition engine, diesel engine, electric motor).

The bulk current injection (BCI) test method is based on current injection into the wiring harness using

a current probe as a transformer where the harness forms the secondary winding. The tubular wave

coupler (TWC) test method is based on a wave coupling into the wiring harness using the directional

coupler principle.

The TWC test method was developed for immunity testing of automotive components with respect to

radiated disturbances in the GHz ranges (GSM bands, UMTS, ISM 2,4 GHz). It is best suited to small

(with respect to wavelength) and shielded device under test (DUT), since in these cases the dominating

coupling mechanism is via the harness.

The electromagnetic disturbance considered in this document is limited to continuous narrowband

electromagnetic fields.

ISO 11451-1 gives definitions, practical use and basic principles of the test methods.

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 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/
4 Test conditions

The applicable frequency range of the BCI and the TWC test methods are direct functions of the

transducer characteristics (current probe or tubular wave coupler). More than one type of transducer

may be required to cover the applicable frequency range.
© ISO 2022 – All rights reserved
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ISO 11451-4:2022(E)
To test automotive electronic systems, the typical applicable frequency range:

— of the BCI test method is 100 kHz to 1 GHz. When an alternative test method is not feasible, then

BCI testing between 400 MHz and 1 GHz may be used and shall be agreed between the users of this

document and documented in the test plan,
— of the TWC test method is 400 MHz to 3 GHz.

The users shall specify the test severity level(s) over the frequency range. Suggested test severity levels

are given in Annex C. These test severity levels are expressed in terms of the equivalent root-mean-

square value of the unmodulated wave.
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, and
— test signal quality.
5 Test location
The tests should be performed in a shielded enclosure.

The distance between the vehicle and all other conductive structures, such as the walls of a shielded

room (with the exception of the ground plane underneath the vehicle) shall be a minimum of 0,5 m.

The test may be alternatively performed in an outdoor test site. The test facility shall be aware of

(national) legal requirements regarding the transmission of electromagnetic fields.

CAUTION — Hazardous voltages and fields may exist within the test area. Care shall be taken to

ensure that the requirements for limiting the exposure of humans to RF energy are met.

6 Test instrumentation
6.1 BCI test method
6.1.1 General

BCI is a method of carrying out immunity tests by inducing disturbance signals directly into the wiring

harness by means of a current injection probe. The injection probe is a current transformer through

which the wires of the device under test (DUT) are passed. Immunity tests are then carried out by

varying the test severity level and frequency of the induced disturbance.
The following equipment is used:
— current injection probe(s);
— current measurement probe(s);

— radio frequency (RF) generator with internal or external modulation capability;

— power amplifier;
© ISO 2022 – All rights reserved
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ISO 11451-4:2022(E)
— power measuring instrumentation to measure the forward and reverse power;
— current measurement equipment.
BCI shall be conducted on each individual system fitted to the vehicle.
6.1.2 Injection probe

An injection probe or set of probes capable of operating over the test frequency range is required to

couple the test signal to the DUT. The probe(s) shall be capable of withstanding the necessary input

power for the maximum test level over the test frequency range regardless of the test set-up loading.

Saturation of the injection probe by test level and by DUT current should be taken into consideration.

6.1.3 Current measurement probe

The current measurement probe or set of probes shall be capable of operating over the test frequency

range.
6.1.4 Stimulation and monitoring of the DUT

The DUT shall be operated as required in the test plan by actuators which have a minimum effect on

the electromagnetic characteristics, e.g. plastic blocks on the push-buttons, pneumatic actuators with

plastic tubes.

Connections to equipment monitoring electromagnetic interference reactions of the DUT may be

accomplished by using fibre-optics, or high-resistance leads. Other type of leads may be used but

require extreme care to minimize interactions. The orientation, length and location of such leads shall

be carefully documented to ensure repeatability of test results.

Any electrical connection of monitoring equipment to the DUT may cause malfunctions of the DUT.

Extreme care shall be taken to avoid such an effect.
6.2 TWC test method
6.2.1 General

The approach of this test method is an equivalent coupling to a plane wave coupling into a wiring

harness of the vehicle. To realize this, a short 50 Ω coaxial line configuration with open ends, an inner

tube-shaped conductor and matched terminations are used to generate a transverse electromagnetic

(TEM) wave inside. The wiring harness leads through the inner conductor of the wave coupler. This

leads to two disturbing components for the DUT: a TEM wave component coupled via the cable, and a

radiated component, caused by the scattering field from the primary TEM wave in the connecting cable

between the coupler and the DUT.
The following equipment is used:
— tubular wave coupler;
— RF generator with internal or external modulation capability;
— power amplifier;
— power measuring instrumentation to measure the forward and reverse power.
TWC shall be conducted on each individual system fitted to the vehicle.
© ISO 2022 – All rights reserved
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ISO 11451-4:2022(E)
6.2.2 Tubular wave coupler

A tubular wave coupler is used to couple the disturbances into the test wiring harness. It shall be

capable of coupling the test power over the test frequency range into the wiring harness and shall have

a sufficiently high coupling and power rating.
6.2.3 50 Ω load resistor

A 50 Ω load resistor is used to match the output of the tubular wave coupler. The power rating shall be

equal or greater than the applied forward power.
6.2.4 Stimulation and monitoring of the DUT
See 6.1.4.
7 Test set-up
7.1 BCI Test methods

There are two test methods for the BCI test: the substitution method and the closed-loop method (see

7.1.1 and 7.1.2, respectively).
7.1.1 Substitution method

Unless otherwise specified in the test plan, the current injection probe shall be mounted around the

harness (150 ± 50) mm from the connector or the outlet aperture of the DUT being tested on the vehicle.

Where the harness contains a number of branches to DUT connectors, the test should be repeated with

the current injection probe(s) clamped around each of the branches (150 ± 50) mm from the branch

termination. Under these test conditions, the measuring probe, if used, shall be left at its previous

distance from the DUT.

Using the pre-calibrated level of forward power, (described in 8.3.1.2.2), conduct a search for events

over the frequency range of the injection probe.

For each event, record the lowest forward power to the probe as the threshold of immunity at different

frequencies.

A current measurement probe may optionally be mounted between the current injection probe and

the DUT. It may provide extra useful information, but it may also modify the test conditions. When

this probe is used, the measured current cannot be used to determine the performance of the DUT, but

should be retained and used during investigative work for the causes of events and the variances in test

conditions after system modifications.
An example of a test configuration shown in Figure 1.
© ISO 2022 – All rights reserved
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ISO 11451-4:2022(E)
Dimensions in millimetres
Key
1 signal generators
2 broadband amplifier
3 RF 50 Ω directional coupler
4 RF power level measuring device or equivalent
5 RF injection probe
6 RF current measurement probe (optional)
7 DUT
8 spectrum analyser or equivalent (optional)
9 others vehicle devices
10 harness
11 shielded enclosure

It is recommended that appropriate ferrite chokes be placed on the coaxial cables to the injection and current

measurement probes.
Figure 1 — Example of BCI test configuration – Substitution method
7.1.2 Closed-loop method with power limitation

Unless otherwise specified in the test plan, the injection probe should be placed at (900 ± 50) mm from

the connector of the DUT.

Unless otherwise specified in the test plan, the current measurement probe shall be placed at

(50 ± 10) mm from the connector of the DUT.

The vehicle and associated equipment are installed in the test location as described in Figure 2.

© ISO 2022 – All rights reserved
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ISO 11451-4:2022(E)
Dimensions in millimetres
Key
1 signal generators
2 broadband amplifier
3 RF 50 Ω directional coupler
4 RF power level measuring device or equivalent
5 RF injection probe
6 RF current measurement probe
7 DUT
8 spectrum analyser or equivalent
9 others vehicle devices
10 harness
11 shielded enclosure

It is recommended that appropriate ferrite chokes be placed on the coaxial cables to the injection and current

measurement probes.
Figure 2 — Example of BCI test configuration – Closed-loop method
7.2 TWC Test methods

Measurements using this method can be affected by coupling between the TWC and the wiring harness

as well as by reflected energy.

Unless otherwise specified in the test plan, the tubular wave coupler shall be placed at (100 ± 10) mm

from the connector or the outlet aperture of the DUT being tested on the vehicle and isolated from any

metallic part of the vehicle. It shall be connected to the high-frequency equipment at the port, which is

closer to the DUT. The 50 Ω load resistor shall be placed isolated from any metallic part of the vehicle at

a minimum distance of 200 mm from the wiring harness and connected to the second port of the TWC.

Where the harness contains a number of branches to DUT connectors, the test should be repeated

with the tubular wave coupler clamped around each of the branches (100 ± 10) mm from the branch

termination.

The vehicle and associated equipment are installed in the test location as described in Figure 3.

© ISO 20
...

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