IEC 61000-4-3:2006/AMD1:2007
(Amendment)Amendment 1 - Electromagnetic compatibility (EMC) - Part 4-3: Testing and measurement techniques - Radiated, radio-frequency, electromagnetic field immunity test
Amendment 1 - Electromagnetic compatibility (EMC) - Part 4-3: Testing and measurement techniques - Radiated, radio-frequency, electromagnetic field immunity test
Amendement 1 - Compatibilité électromagnétique (CEM) - Partie 4-3: Techniques d'essai et de mesure - Essai d'immunité aux champs électromagnétiques rayonnés aux fréquences radioélectriques
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IEC 61000-4-3
Edition 3.0 2007-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
AMENDMENT 1
AMENDEMENT 1
Electromagnetic compatibility (EMC) –
Part 4-3: Testing and measurement techniques – Radiated, radio-frequency,
electromagnetic field immunity test
Compatibilité électromagnétique (CEM) –
Partie 4-3: Techniques d’essai et de mesure – Essai d’immunité aux champs
électromagnétiques rayonnés aux fréquences radioélectriques
IEC 61000-4-3 A1:2007
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IEC 61000-4-3
Edition 3.0 2007-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
AMENDMENT 1
AMENDEMENT 1
Electromagnetic compatibility (EMC) –
Part 4-3: Testing and measurement techniques – Radiated, radio-frequency,
electromagnetic field immunity test
Compatibilité électromagnétique (CEM) –
Partie 4-3: Techniques d’essai et de mesure – Essai d’immunité aux champs
électromagnétiques rayonnés aux fréquences radioélectriques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
R
CODE PRIX
ICS 33.100.20 ISBN 2-8318-9354-2
– 2 – 61000-4-3 Amend.1 © IEC:2007
FOREWORD
This amendment has been prepared by subcommittee 77B: High frequency phenomena of IEC
technical committee 77: Electromagnetic compatibility.
The text of this amendment is based on the following documents:
FDIS Report on voting
77B/546/FDIS 77B/556/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the maintenance result date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
_____________
Page 3
CONTENTS
Add, to the existing list of annexes, the following new title:
Annex I (informative) Calibration method for E-field probes
Page 25
Add, at the end of the sixth dashed item (beginning with “– An isotropic field sensor”), the
following new sentence:
Annex I provides a calibration method for E-field probes.
Page 111
Add the following new annex:
61000-4-3 Amend.1 © IEC:2007 – 3 –
Annex I
(informative)
Calibration method for E-field probes
I.1 Overview
E-field probes with broad frequency range and large dynamic response are extensively used
in the field uniformity calibration procedures in accordance with IEC 61000-4-3. Among other
aspects, the quality of the field probe calibration directly impacts the uncertainty budget of a
radiated immunity test.
Generally, probes are subject to relatively low field strengths, e.g. 1 V/m – 30 V/m, during the
field uniformity calibration in accordance with IEC 61000-4-3. Therefore a calibration of the E-
field probes used within IEC 61000-4-3 shall take the intended frequency and dynamic ranges
into consideration.
Currently probe calibration results may show differences when the probe is calibrated in
different calibration laboratories. Therefore the environment and method for a field probe
calibration are to be specified. This annex provides relevant information on calibration of
probes to be used in IEC 61000-4-3.
For frequencies above the several hundred megahertz to gigahertz range, using standard gain
horn antennas to establish a standard field inside an anechoic chamber is one of the most
widely used methods for calibrating probes for IEC 61000-4-3 applications. However, there is
a lack of an established method for validating the test environment for field probe calibrations.
In using this method, differences have been observed between calibration laboratories,
beyond their reported measurement uncertainties.
Field probe calibrations in the 80 MHz to a few hundred megahertz range that are usually
carried out in TEM waveguides are generally found to be more reproducible.
This informative annex therefore concentrates on improving the probe calibration procedures
with horn antennas in anechoic chambers to which a comprehensive calibration procedure is
depicted.
I.2 Probe calibration requirements
I.2.1 General
The calibration of E-Field probes intended to be used for UFA calibration procedure as
defined in IEC 61000-4-3 shall satisfy the following requirements.
I.2.2 Calibration frequency range
The frequency range shall normally cover 80 MHz to 6 GHz but it may be limited to the
frequency range required by the tests.
I.2.3 Frequency steps
To be able to compare test results between different calibration laboratories, it is necessary to
use fixed frequencies for the calibration.
– 4 – 61000-4-3 Amend.1 © IEC:2007
80 MHz to 1 GHz:
Use the following frequencies for the calibration of E-field probes (typically 50 MHz step
width)
80, 100, 150, 200,…, 950, 1 000 MHz
1 GHz to 6 GHz:
Use the following frequencies for the calibration of E-field probes (200 MHz step width)
1 000, 1 200, 1 400,…, 5 800, 6 000 MHz
NOTE It is not intended to measure a probe at 1 GHz twice, but in case it is used up to or from 1 GHz, the probe
needs to be measured at that frequency.
I.2.4 Field strength
The field strength at which a probe is calibrated should be based on the field strength
required for the immunity test. As the preferred method for uniformity field calibration is
carried out at field strength of at least 1,8 times the field strength to be applied to the EUT, it
is recommended that the probe calibration be carried out at twice the intended test field
strength (see Table I.1). If a probe is to be used at different field levels, it has to be calibrated
at multiple levels according to its linearity, at least the minimum and maximum levels. See
also I.3.2.
NOTE 1 This also covers the 1 dB compression requirement of the power amplifier.
NOTE 2 The calibration is performed using CW signals without modulation.
Table I.1 – Calibration field strength level
Calibration level Calibration field strength
1 2 V/m
2 6 V/m
3 20 V/m
4 60 V/m
X Y V/m
NOTE X,Y is an open calibration level which can be higher
or lower than one of the other levels 1-4. This level may be
given in the product specification or test laboratory.
I.3 Requirements for calibration instrumentation
I.3.1 Harmonics and spurious signals
Any harmonics or spurious signals from the power amplifiers shall be at least 20 dB below the
level at the carrier frequency. This is required for all field strength levels used during
calibration and linearity check. Since the harmonic content of power amplifiers is usually
worse at higher power levels, the harmonic measurement may be performed only at the
highest calibration field strength. The harmonic measurement can be performed using a
calibrated spectrum analyzer which is connected to the amplifier output through an attenuator,
or through a directional coupler.
NOTE 1 The antenna may have additional influence on harmonic content and may need to be checked separately.
Calibration laboratories shall perform a measurement to validate that the harmonic and/or
spurious signals from the amplifier satisfy the requirements for all measurement setups. This
61000-4-3 Amend.1 © IEC:2007 – 5 –
may be done by connecting a spectrum analyzer to Port 3 of the directional coupler (replacing
the power meter sensor with the spectrum analyzer input – see Figure I.2).
NOTE 2 It should be assured that the power level does not exceed the maximum allowable input power of the
spectrum analyzer. An attenuator may be used.
The frequency span shall cover at least the third harmonic of the intended frequency. The
validation measurement shall be performed at the power level that will generate the highest
intended field strength.
Harmonic suppression filters may be used to improve the spectrum purity of the power
amplifier(s) (see Annex D).
I.3.2 Linearity check for probe
The linearity of the probe which is used for the chamber validation according to I.4.2.5 shall
be within ±0,5 dB from an ideal linear response in the required dynamic range (see Figure I.1).
Linearity shall be confirmed for all intended range settings if the probe has multiple ranges or
gain settings.
In general probe linearity does not change significantly with frequency. Linearity checking can
be performed at a spot frequency that is close to the central region of the intended use of
frequency range, and where the probe response versus frequency is relatively flat. The
selected spot frequency is to be documented in the calibration certificate.
The field strength for which the linearity of the probe is measured should be within –6 dB to
+6 dB of the field strength which is used during the validation of the chamber, with a
sufficiently small step size, e.g. 1 dB. Table I.2 shows an example of the field strength levels
to be checked for a 20 V/m application.
Table I.2 – Example for the probe linearity check
Calibration field
Signal level
strength
dB V/m
-6,0 13,2
-5,0 14,4
-4,0 14,8
-3,0 15,2
-2,0 16,3
-1,0 18,0
0 20,0
1,0 22,2
2,0 24,7
3,0 27,4
4,0 30,5
5,0 34,0
6,0 38,0
– 6 – 61000-4-3 Amend.1 © IEC:2007
100,0
Nonlinear curve
10,0
1,0
–6,0 –4,0 –2,0 0,0 2,0 4,0 6,0
Signal level dB
IEC 2043/07
Figure I.1 – Example of linearity for probe
I.3.3 Determination of the gain of the standard horn antennas
Far field gain of the standard pyramidal horn antennas can be determined fairly accurately
(less than 0,1 dB of uncertainties have been reported in [1] ). The far-field gain is typically
valid for distances greater than 8D / λ (where D is the largest dimension of the horn aperture,
and λ is the wavelength). Calibrations of field probes at such distances may not be practical
due to the large anechoic chamber and high power amplifiers required. Field probes are
typically calibrated in the near field region of the transmitting antennas. The near-field gain of
standard gain horn antennas have been determined by using equations such as those
described in [2]. The gain is computed based on the physical dimensions of a standard
pyramidal horn, and by assuming a quadratic phase distribution at the horn aperture. The gain
determined in this manner is inadequate for use in performing the chamber VSWR test and
subsequent probe calibrations.
The equations (as given in [2]) were derived using aperture integration, by assuming that no
reflection occurs at the aperture of the horn and that the field incident on the aperture is a
TE mode, but with a quadratic phase distribution across the aperture. Some approximations
were applied during the integration to obtain the close form result. Other effects such as
multiple reflections from the horn edge, and higher order modes at the aperture are not
accounted for. Depending on the frequency and horn design, the error is generally in the
order of ±0,5 dB, but can be larger.
For better accuracy, a numerical method using full wave integration can be used. For example,
the uncertainties in the gain calculation by a numerical method can be reduced to less than
5 % [3].
The gain of a horn antenna can also be determined experimentally. For example, the gain can
be determined at reduced distances with a three-antenna method by an extrapolation
technique, such as that described in [4], or some variations of the method.
___________
1)
Figures in square brackets refer to the reference documents in Clause I.6.
Calibration field strength V/m
61000-4-3 Amend.1 © IEC:2007 – 7 –
It is recommended that the distance between the horn antenna and the probe under test be at
least 0,5D / λ during the calibration. Large uncertainties in determining gains can result from
a closer distance. The standing waves between the antenna and the probe can also be large
for closer distances, which again would result in large measurement uncertainties in the
calibration.
I.4 Field probe calibration in anechoic chambers
I.4.1 Calibration environments
The probe calibration should be performed in a fully anechoic room (FAR) or in a semi-
anechoic chamber with absorbers on the ground plane which satisfies the requirement of I.4.2.
When a FAR is used, the recommended minimum size of the FAR internal working volume for
performing the probe calibration is 5 m (D) × 3 m (W) × 3 m (H).
NOTE 1 For frequencies above several hundred MHz, using standard gain horn antennas to establish a standard
field inside an anechoic chamber is one of the most widely used methods for calibrating field probes for
IEC 61000-4-3 applications. At lower frequencies, such as 80 MHz to several hundred MHz, the use of an anechoic
chamber may not be practical. So the field probe may be calibrated in other facilities also used for immunity tests
against electromagnetic fields. Therefore, TEM waveguides etc. are included in this annex as alternative calibration
environments for these lower frequencies.
The system and the environment used for probe calibration shall meet the following
requirements.
NOTE 2 Alternatively, the electric field can be established using a transfer probe (see I.5.4).
I.4.2 Validation of anechoic chambers for field probe calibration
The probe calibration measurements assume a free space environment. A chamber VSWR
test using a field probe shall be performed to determine whether it is acceptable for
subsequent probe or sensor calibration. The validation method characterizes the performance
of the chamber and absorbing material.
Each probe has a specific volume and physical size, for example the battery case and/or the
circuit board. In other calibration procedures, a spherical quiet zone is guaranteed in the
calibration volume. The specific requirements of this annex concentrate on a VSWR test for
test points located at the antenna beam axes.
Test fixtures and their influences (such as the fixtures to hold the probe, which may be
exposed to electromagnetic fields and interfere with the calibration) cannot be entirely
evaluated. A separate test is required to validate the influences of the fixtures.
I.4.2.1 Measuring net power to a transmitting device using directional couplers
Net power delivered to a transmitting device can be measured with a 4-port bi-directional
coupler, or two 3-port single directional couplers connected back-to-back (forming the so-
called “dual directional coupler”). A common setup using a bi-directional coupler to measure
the net power to a transmitting device is shown in Figure I.2.
– 8 – 61000-4-3 Amend.1 © IEC:2007
Power meters
PM1 PM2
3 4
Antenna
Forward Reverse
Input Output
Source
IEC 2044/07
Figure I.2 – Setup for measuring net power to a transmitting device
The forward coupling, reverse coupling and transmission coupling are defined as the following
equations in case where each port is connected with a matched load and a matched source:
P
C = ,
fwd
P
P
C = ,
rev
P
P
C = ,
trans
P
where P , P , P , P are the respective powers at each port of the directional coupler.
1 2 3 4
The net power delivered to the transmitting device is then:
C PM
trans 2
P = PM − ,
net 1
C C
fwd rev
where PM and PM are the power meter readings in linear units.
1 2
Where the VSWR of the antenna is known, then a single three-port coupler can be used. For
example, when the antenna has a VSWR of 1,5 this is equivalent to a voltage reflection
coefficient (VRC) of 0,2.
The accuracy is affected by the directivity of the coupler. The directivity is a measure of the
coupler’s ability to isolate the forward and the reverse signals. For a well-matched
transmitting device, the reverse power is much smaller than the forward power. The effect of
the directivity is therefore less important than in a reflectivity application. For example, when
the transmitting antenna has a VSWR of 1,5 and the coupler has a directivity of 20 dB, the
absolute maximum uncertainty in the net power due to the finite directivity is 0,22 dB –
0,18 dB = 0,04 dB with a U-shaped distribution (where the 0,22 dB is the loss of the apparent
incident power due to VSWR of 1,5).
The net power delivered to the transmitting device is then:
P = C PM (1 −VRC )
net fwd 1
61000-4-3 Amend.1 © IEC:2007 – 9 –
I.4.2.2 Establishing a standard field using horn antennas
The gain of the horn antenna is determined by the methods described in I.3.3. The on-axis
electric field (in V/m) is determined by
η P g
0 net
E = ,
4π d
where η = 377 Ω for free space, P (in W) is the net power determined by the method
net
described in I.4.2.1, g is the numeric gain of the antenna determined by I.3.3 and d (in m) is
the distance from the antenna aperture.
I.4.2.3 Chamber validation test frequency range and frequency steps
The chamber VSWR test shall cover the frequency range for which the calibration of the
probe is intended, and use the same frequency steps as given in I.2.3.
VSWR tests shall be carried out in the chamber at the lowest and highest frequencies of
operation of each antenna. Where narrow band absorbers are used, e.g. ferrites, more
frequency points may need to be measured. The chamber should be used for probe
calibration only in the frequency range where it meets the VSWR criteria.
I.4.2.4 Chamber validation procedure
The chamber used for the probe calibration shall be verified by the following procedure,
except in cases where the physical conditions of the chamber do not allow it to be used. In
such cases the alternative method of I.4.2.7 can be applied.
The probe shall be located at the measurement position using a support material with a low
permittivity (e.g. styrene foam) in accordance with Figure I.3 and Figure I.4.
A field probe is placed at the location where it will be used for calibration. Its polarization and
position along the boresight of the transmitting horn antenna will be varied to determine the
chamber VSWR. The transmit antenna shall be the same for both the chamber VSWR test
and the probe calibration.
The arrangements of the standard gain horn antenna and the probe inside the chamber are
shown in Figure I.3. The probe and the horn antenna shall be set on the same horizontal axis
with a separation distance L measured from the front face of the antenna to the centre of the
probe.
In every case the field probe shall be laterally positioned in the centre of the horn antenna
face.
– 10 – 61000-4-3 Amend.1 © IEC:2007
Transmit horn antenna
L = 1 m ± 0,005 m
Field probe
Standard gain
L L L
–10 cm 0 cm +20 cm
horn antenna
Styrene foam
IEC 2045/07
Figure I.3 – Test setup for chamber validation test
L
L ΔL L ΔL +20 cm
–10 cm
0 cm
IEC 2046/07
Figure I.4 – Detail for measurement position ΔL
The setup is illustrated in Figure I.3 and Figure I.4, where L to L is the probe
-
10 cm +20 cm
calibration distance, measured from the face of the horn antenna to the centre of the field
probe. L is defined as position 0.
0 cm
The positions will be L-10 cm, L-8 cm, L-6 cm, …,L , L+2 cm, L+4 cm, …, L+20 cm, ΔL = 2 cm.
If the probe is placed in the near field of the transmitting horn antenna (distance < 2 D /λ,
where D is the largest dimension of the antenna and λ is the free space wavelength), the gain
of the transmitting antenna is not constant, and may need to be determined for each position.
A constant power creating certain field strength (e.g. 20 V/m) at 1 m distance is applied for all
probe positions. With the transmit antenna and field probe both vertically polarized, the probe
readings for all positions at all frequencies are recorded. The test is repeated with antenna
and probe horizontally polarized.
All the readings shall satisfy the requirement shown in I.4.2.5.
I.4.2.5 VSWR acceptance criteria
VSWR measurement results shall be compared by using the following procedure. For the
calculation of the field strength, refer to I.4.2.2.
a) Calculation of the field strength
h>0,8 m
61000-4-3 Amend.1 © IEC:2007 – 11 –
The electrical field strength in the spatial area between the distances 90 cm and 120 cm is
calculated in 2 cm steps for each frequency.
This calculation is based on the E-field strength of a 1 m distance used for verification.
b) Data adjustment
Data is adjusted with the following process because the probe used for the VSWR
measurement may not deliver a reading equal to the calculated field strength.
– E-field strength indication value of the probe at a 1 m distance shall be adjusted to the 1 m
position of the calculation. The obtained difference between probe indications and
calculated strength is used as the correction value k for all the data at 90 cm and 120 cm.
For example: comparison between probe measurement value V (e.g. 21 V/m) and
mv
calculated value V (e.g. 20 V/m) at 1 m distance. In this case the correction value k is
cv
V – V = −1 V/m.
cv mv
– The correction value k shall be added to the data that is observed at 90 cm to 120 cm
measurement positions.
– The same calculation shall be applied to all measurement values of all measured
frequencies. In the case of the above example, k = −1 V/m. Therefore k = −1 is added to
all probe measurement value data.
25 25
Measurement curve Data adjustment curve
20 20
Calculation curve
Distance 90 cm to 120 cm Distance 90 cm to 120 cm
15 15
90 120 90 120
Position cm Position cm
IEC 2047/07 IEC 2048/07
Figure I.5 – Example of data adjustment
c) Comparison of measurement data and calculation data
When the data difference in calculation curve and measurement curve exceeds ± 0,5 dB in
any measurement position, the chamber shall not be used for probe calibration.
NOTE The 0,5 dB criterion is established according to the measurement uncertainty budget and has been verified
in several existing chambers that are suitable for calibration of field probes (including at least one national
measurement institute calibration facility). It is anyhow only one contributor to the overall uncertainty.
Some field probes have a metal box or a pole such as the battery or a circuit. These units
may cause reflection errors at certain distances and frequencies. When these probes are
used, the influence of the reflection shall be minimized e.g. by rotating the probe or changing
its orientation.
I.4.2.6 Probe fixture validation
The probe fixture may cause reflections of electromagnetic fields during the probe calibration.
Therefore, the influence of the fixture on the calibration results shall be checked in advance.
The procedure defined in this clause shall be performed for any new probe fixtures to be used.
Field strength V/m
Field strength V/m
– 12 – 61000-4-3 Amend.1 © IEC:2007
Procedure:
a) Place the probe on a reference support made of a material with a relative permittivity of
less than 1,2 and a dielectric loss tangent less than 0,005. The location of the probe shall
be the same as for the calibration setup. The reference fixture should be as small as
possible. Any other supporting structures shall be as non-intrusive as possible, and at
least 50 cm away from the probe. Support structures in front (between the antenna and
the probe) or behind the probe should be avoided.
b) Generate a standard field that is within the dynamic range of the probe at the calibration
position.
c) Record the probe reading for all calibration frequency points. Rotate or re-position the
probe as necessary for all calibration geometries (for three-axis isotropic field probes,
each axis may need to be aligned separately), and repeat steps 1 and 2. Record probe
readings for all orientations.
d) Remove the reference fixture and replace it with the calibration fixture to be qualified.
Repeat steps 2, and 3.
e) Compare results from steps 3 and 4. The difference between the readings with the two
fixtures for the same probe orientation shall be less than ± 0,5 dB.
I.4.2.7 Alternative chamber validation procedure
This alternative chamber validation procedure is applicable when the validation procedure of
I.4.2.4 cannot be applied.
A field probe is placed at the location where it will be used for calibration. Its polarization and
position along the boresight of the transmitting horn antenna will be varied to determine the
chamber VSWR. The transmit antenna shall be the same for both the chamber VSWR test
and the probe calibration.
Transmit horn antenna
1 m
Field probe
Optional
Standard gain
position
Styrene
horn antenna
foam
IEC 2049/07
Figure I.6 – Example of the test layout for antenna and probe
61000-4-3 Amend.1 © IEC:2007 – 13 –
1 m (L )
0 cm
1 m (L )
–30 cm
Field probe
ΔL
Standard gain
horn antenna
L L L
–30 cm 0 cm +30 cm
IEC 2050/07
Figure I.7 – Test setup for chamber validation test
The setup is illustrated in Figures I.6 and I.7, where the probe calibration distance, measured
from the face of the horn antenna to the centre of the field probe is maintained at a fixed
distance, i.e. 1 m.
It is desirable to use material with low permittivity for the probe fixture to avoid influences on
the measurement. The fixture used for probe calibration shall be evaluated separately (see
I.4.2.6).
The positions will be L - 30 cm, L - 25 cm, L - 20 cm, …, L , L + 5 cm, L + 10 cm, …, L +
30 cm, ΔL is 5 cm.
A constant field, e.g. 20 V/m, is generated for all positions. The generated field strength
needs to be within the dynamic range of the field probe. With the transmit antenna and field
probe both vertically polarized: record the probe reading for all positions at all frequencies.
Repeat the test with the antenna and probe horizontally polarized.
At each frequency, there will be 26 independent probe readings (13 positions, and two
polarizations). The maximum spread of the readings at each frequency shall be less than
±0,5 dB.
+ 0,5 dB
Position data for
L to L
–30 cm +30 cm
0 dB
– 0,5 dB
1 1,5 2 2,5 3 3,5 4 4,5 5 5,5
Frequency GHz
IEC 2051/07
Figure I.8 – Example alternative chamber validation data
I.4.3 Probe calibration procedure
Many modern probes have internal correction factors to provide a linear response. Calibration
laboratories may adjust the factors during calibration to give a probe response of ±0,5 dB
from the ideal. If adjustments are made, the calibration laboratory should report the response
both before and after adjustment.
– 14 – 61000-4-3 Amend.1 © IEC:2007
The linearity check process should be applicable to the probe to be calibrated. For the
influences of linearity on the calibration system, refer to I.3.2.
NOTE When it is not possible to adjust the probe, any non-linearity should be compensated for by the user when
carrying out the field uniformity calibration.
The probe calibration shall use the measurement system/environment, which satisfies the
requirement of I.4.
I.4.3.1 Test setup
A fixture that is not fully qualified according to I.4.2.6 can result in large measurement
uncertainties. Therefore, the probe fixture validated per I.4.2.6 shall be used.
The calibration of the field probe should be done according preferably to the user
specification or manufacturer’s specification regarding the probe orientation. This orientation
shall also be used in the test laboratory to limit the effect of isotropy. If the manufacturer does
not specify any field probe orientation in the data sheet, the calibration should be performed
in the probe orientation which can be considered as the “normal use” orientation of the probe
or according to a preferred orientation defined by the test lab (which will use the probe). In
any case the calibration report shall include the field probe orientation for which the
calibration was undertaken.
The example of the measurement setup is shown in the Figures I.9 and I.10.
1 m ± 0,005 m
Field probe
Same as
Standard gain
verification
horn antenna test layout
IEC 2052/07
Figure I.9 – Field probe calibration layout
Standard gain
1 m ± 0,005 m
horn antenna
Field probe
IEC 2053/07
Figure I.10 – Field probe calibration layout (Top view)
61000-4-3 Amend.1 © IEC:2007 – 15 –
I.4.3.2 Calibration report
The measurement results obtained in consideration of I.4.3.1 shall be reported as a
calibration report.
This calibration report shall contain at least the following:
a) calibration environment;
b) probe manufacturer;
c) type designation;
d) serial number;
e) calibration date;
f) temperature and humidity;
g) details of the calibration data:
– frequency;
– applied field strength (V/m);
– probe reading (V/m);
– probe orientation;
h) measurement uncertainty.
NOTE IEEE Std 1309 [2] includes some guidance for probe-calibration measurement uncertainty.
I.5 Alternative probe calibration environments and methods
This clause describes the environment requirement for alternative calibration sites, e.g.
necessary for the calibration in the low frequency range.
The calibration can be done in environments defined as independent from the test
environment described in IEC 61000-4-3. In contrast to the equipment, which is tested for
immunity, field probes are typically small and usually not equipped with conducting cables.
I.5.1 Field probe calibration using TEM cells
A rectangular TEM cell can be used to establish standard fields for field probe calibrations.
The upper usable frequency of a TEM cell can be determined by methods described in 5.1 of
IEC 61000-4-20.The upper frequency of a TEM cell is typically a few hundreds MHz. The field
at the centre of a TEM cell between the septum and the top or bottom plate is calculated from:
Z P
0 net
E = (V/m),
h
where Z is the characteristic impedance of the TEM cell (typically 50 Ω), P is the net power
0 net
in Watt, which is determined according to I.4.2.1, h is the separation distance between the
septum and the top or bottom plate (in m).
The VSWR of the TEM cell should be kept small, e.g. less than 1,3 to minimize the
measurement uncertainties.
An alternative method of measuring P is to use a calibrated, low VSWR attenuator and
net
power sensor connected to the output port of the TEM cell.
– 16 – 61000-4-3 Amend.1 © IEC:2007
I.5.2 Field probe calibration using waveguide chambers
b
E
a
IEC 2054/07
Figure I.11 – Cross-sectional view of a waveguide chamber
Calibration labs shall ensure that waveguide chambers operate in their dominant TE mode.
Frequencies that can excite higher order modes shall be avoided. Waveguide manufacturers
typically specify the frequency ranges for which only a dominant mode can exist. This can
also be determined from the dimensions of the waveguide. The use of waveguide chambers is
limited to approximately 300 MHz to 1 000 MHz with typical sized probes.
For a waveguide chamber with inner dimensions of a (m) x b (m) (a>b), the cut-off frequency
of the dominant TE mode is:
()f = ,
c
2a με
where μ and ε are the permeability and permittivity of the waveguide media. For air-filled
-1 -1
waveguides, μ =μ = 400π nHm and ε =ε = 8,854 pFm . The cut-off frequency for an air-
0 0
filled waveguide chamber is:
()f = MHz.
c
a
The root-mean-square electric field at the centre of the waveguide is:
2η P
0 net
E = (V/m),
ab 1−()()f / f
c
where f (in MHz) is the frequency of operation, η = 377 Ω for air-filled waveguide, P (in W)
net
is the net power delivered to the waveguide, and is determined by the method described in
I.4.2.1. Note that the field inside a waveguide chamber is not a TEM wave, and the field is the
largest at the centre of the waveguide (with a sinusoidal distribution, tapering to zero on the
sidewalls). It is recommended that field probe calibrations be performed at the centre of the
waveguide, where the field distribution has less variation (is more uniform) than at other
locations. For more information on waveguide including how to calculate cut-off frequencies
for other modes, refer to [5].
I.5.3 Field probe calibration using open-ended waveguides
An analytical solution and an empirical solution for the near-field gain of open-ended
waveguides are provided in [6]. Since a simple theoretical solution for the near-field gain of
open-ended waveguides is not available, one should determine the near-field gain of an open-
ended waveguide by either full-wave numerical techniques or by measurement techniques as
described in [4].
61000-4-3 Amend.1 © IEC:2007 – 17 –
Once the near-field gain of the open-ended waveguides is determined, the calibration shall
follow the procedure listed in I.4.3.
I.5.4 Calibration of field probes by gain transfer method
A transfer probe can be used to establish standard fields in a field-generating device (working
standard device). The transfer probe response can be either determined by theoretical
computations (for probes such as dipoles), or by calibrations performed according to the
methods described in I.5.1 or I.5.2. The transfer function of the working standard, such as a
GHz TEM cell, can be determined from the transfer probe. The field distribution in the working
standard device should be mapped by the transfer probe; i.e. it has to be measured at as
many locations as necessary to assess the field homogeneity in the test volume. Once the
transfer function of the working standard device is known, probe calibration can be performed
at other power levels provided that the working standard device is linear. A probe to be
calibrated shall be placed at the same location where the transfer probe has been.
The transfer method is accurate if the following conditions are met:
• the setup does not change between the transfer and calibration procedures;
• the probe position during measurements is reproduced;
• the transmitted power remains the same;
• the probe under test is similar in construction (size and element design) to the transfer
probe;
• the cables connecting the sensor head and readout do not disturb or pick up the field;
• the working standard device is largely anechoic.
References [7] and [8] have more information on this method.
I.6 Reference documents
[1] STUBENRAUCH, C., NEWELL, C. A. C., REPJAR, A. C. A., MacREYNOLDS, K.,
TAMURA D. T., LARSON, F. H., LEMANCZYK, J., BEHE, R., PORTIER, G., ZEHREN, J.
C., HOLLMANN, H., HUNTER, J. D., GENTLE, D. G., and De VREEDE, J. P. M.
International Intercomparison of Horn Gain at X-Band. IEEE Trans. On Antennas and
Propagation, October 1996, Vol. 44, No. 10.
[2] IEEE 1309, Calibration of Electromagnetic Field Sensors and Probes, Excluding
Antennas, from 9 kHz to 40 GHz.
[3] KANDA, M. and KAWALKO, S. Near-zone gain of 500 MHz to 2.6 GHz rectangular
standard pyramidal horns. IEEE Trans. On EMC, 1999, Vol. 41, No. 2.
[4] NEWELL, Allen C., BAIRD, Ramon C. and Wacker, Paul F. Accurate measurement of
antenna gain and polarization at reduced distances by extrapolation technique. IEEE
Trans. On Antennas and Propagation, July 1973, Vol. AP-21, No. 4.
[5] BALANIS, C. A. Advanced Engineering Electromagnetics. John Wiley & Sons, Inc.,
1989, pp 363-375.
[6] WU, Doris I. and KANDA, Motohisa. Comparison of theoretical and experimental data
for the near field of an open-ended rectangular waveguide. IEEE Trans. On
Electromagnetic Compatibility, November 1989, Vol. 31, No. 4.
[7] GLIMM, J., MÜNTER, K., PAPE, R., SCHRADER, T. and SPITZER, M. The New National
Standard of EM Field Strength; Realisation and Dissemination. 12th Int. Symposium on
EMC, Zurich, Switzerland, February 18-20, 1997, ISBN 3-9521199-1-1, pp. 611-613.
– 18 – 61000-4-3 Amend.1 © IEC:2007
[8] GARN, H., BUCHMAYR, M., and MULLNER, W. Precise calibration of electric field
sensors for radiated-susceptibility testing. Frequenz 53 (1999) 9-10, Page 190-194.
___________
– 20 – 61000-4-3 Amend.1 © CEI:2007
AVANT-PROPOS
Le présent amendement a été établi par le sous-comité 77B: Phénomènes haute fréquences,
du comité d'études 77 de la CEI: Compatibilité électromagnétique.
Le texte de cet amendement est issu des documents suivants:
FDIS Rapport de vote
77B/546/FDIS 77B/556/RVD
Le rapport de vote indiqué dans le tableau ci-dessus donne toute information sur le vote ayant
abouti à l'approbation de cet amendement.
Le comité a décidé que le contenu de cet amendement et de la publication de base ne sera
pas modifié avant la date de maintenance indiquée sur le site web de la CEI sous
"http://webstore.iec.ch" dans les données relatives à la publication recherchée. A cette date,
la publication sera
• reconduite,
• supprimée,
• remplacée par une édition révisée, ou
• amendée.
_____________
Page 2
SOMMAIRE
Ajouter à la liste existante des annexes, le nouveau titre suivant:
Annexe I (informative) Méthode d’étalonnage des sondes de champ E
Page 24
Ajouter, à la fin du sixième tiret (commençant par « – Une sonde de champ isotropique »), la
nouvelle phrase suivante:
L’Annexe I donne une méthode d’étalonnage des sondes de champ E.
Page 110
Ajouter la nouvelle annexe comme suit:
61000-4-3 Amend.1 © CEI:2007 – 21 –
Annexe I
(informative)
Méthode d’étalonnage des sondes de champ E
I.1 Vue d’ensemble
Les sondes de champ E à large gamme de fréquences et à réponse dynamique élevée sont
très souvent utilisées dans les procédures d’étalonnage de l’uniformité des champs selon la
CEI 61000-4-3. Entre autres aspects, la qualité de l’étalonnage de la sonde de champ a un
impact direct sur le budget d'incertitude d'un essai d'immunité aux champs rayonnés.
Généralement, les sondes sont soumises à des valeurs de champs relativement faibles, par
exemple 1 V/m – 30 V/m pendant l’étalonnage d’uniformité de champ conformément à la
CEI 61000-4-3. C’est pourquoi l’étalonnage des sondes de champs E utilisées dans la
CEI 61000-4-3 doit tenir compte des gammes de fréquences et de dynamiques prévues.
Actuellement, les résultats de l’étalonnage d’une sonde peuvent présenter des différences
lorsqu’elle est étalonnée dans des laboratoires différents. C’est pourquoi l’environnement et
la méthode d’étalonnage de la sonde de champ qui est utilisée doivent être spécifiés. La
présente annexe fournit les informations pertinentes sur l’étalonnage des sondes à utiliser
dans la CEI 61000-4-3.
Pour des fréquences supérieures à plusieurs centaines de MHz jusqu’à la gamme des GHz,
l’utilisation d’antennes cornet à gain standard, dans le but d’établir un champ standard à
l’intérieur d’une chambre anéchoïque, est une des méthodes les plus largement répandues
afin d’étalonner des sondes pour des applications selon la CEI 61000-4-3. Cependant, il y a
un manque de méthode établie pour la validation de l’environnement d’essai pour les
étalonnages des sondes de champ.
En utilisant cette méthode, des différences ont été observées entre laboratoires d’étalonnage,
au-delà des incertitudes de mesure qu’ils rapportent également.
Les étalonnages entre 80 MHz et quelques centaines de MHz de sondes de champ qui sont
habituellement réalisés dans des guides d’onde TEM sont généralement plus reproductibles.
Cette annexe informative se concentre par conséquent sur l’amélioration des procédures
d’étalonnage de sondes,
...
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