ISO/TR 10305-2:2003

TECHNICAL ISO/TR
REPORT 10305-2
First edition
2003-02-15
Road vehicles — Calibration of
electromagnetic field strength measuring
devices —
Part 2:
IEEE standard for calibration of
electromagnetic field sensors and
probes, excluding antennas, from 9 kHz
to 40 GHz
Vehicules routiers — Étalonnage des appareils de mesure de l'intensité
d'un champ électromagnétique —
Partie 2: Méthode normalisée de l'IEEE pour l'étalonnage des capteurs
et des sondes de champ électromagnétique, à l'exclusion des
antennes, entre 9 kHz et 40 GHz

Reference number
©
ISO 2003
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©  ISO 2003
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ii © ISO 2003 — All rights reserved

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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
In exceptional circumstances, when a technical committee has collected data of a different kind from that
which is normally published as an International Standard (“state of the art”, for example), it may decide by a
simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely
informative in nature and does not have to be reviewed until the data it provides are considered to be no
longer valid or useful.
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.
ISO/TR 10305-2 was prepared by the US Institute of Electrical and Electronics Engineers (IEEE) (as
IEEE 1309-1996) and was adopted without modification by Technical Committee ISO/TC 22, Road vehicles,
Subcommittee SC 3, Electrical and electronic equipment.
This first edition of ISO/TR 10305-2, together with that of ISO/TR 10305-1, cancels and replaces the first
edition of ISO/TR 10305, which has been technically revised.
ISO/TR 10305 consists of the following parts, under the general title Road vehicles — Calibration of
electromagnetic field strength measuring devices:
 Part 1: Devices for measurement of electromagnetic fields at frequencies > 0 Hz
 Part 2: IEEE standard for calibration of electromagnetic field sensors and probes, excluding antennas,
from 9 kHz to 40 GHz
Introduction
The necessity for EMC (electromagnetic compatibility) testing of road vehicles and their components has led
to the publication of a number of standardized test procedures. The need, too, for a standardized method for
the calibration of field strength measuring devices was seen by the responsible ISO subcommittee. As no
such International Standard was at the time available from either ISO or IEC, ISO/TR 10305 was published in
1992, based on the amended 1975 edition of the US National Bureau of Standards (now the National Institute
of Standards and Technology, NIST) report, NBSIR 75-804.
That document having been considered incomplete, two new calibration methods were independently
developed by DIN, the German Institute for Standardization, and by IEEE, the US Institute of Electrical and
Electronics Engineers. It was decided to publish the methods as the two parts of a Technical Report replacing
ISO/TR 10305:1992. Part 1 is an English translation of part 26 of DIN VDE 0847 and part 2 is the adoption,
without modification, of IEEE std 1309-1996. Each of the two parts should be considered as independent of
the other, no effort having been made to combine them.
The user of either method is kindly requested to report on the experience to ISO/TC 22/SC 3.
In the event of IEC publishing a general calibration procedure as an International Standard, ISO/TR 10305
could be withdrawn, as there is no anticipated need for special calibration methods for use in the automotive
industry.
iv © ISO 2003 — All rights reserved

TECHNICAL REPORT ISO/TR 10305-2:2003(E)

Road vehicles — Calibration of electromagnetic field strength
measuring devices —
Part 2:
IEEE standard for calibration of electromagnetic field sensors
and probes, excluding antennas, from 9 kHz to 40 GHz
1 Scope
This part of ISO/TR 10305 specifies techniques for calibrating electromagnetic field sensors and probes,
excluding antennas, used in automotive testing for the measurement of magnetic fields at frequencies from
9 kHz to 40 GHz. In the automotive field, these field strength measuring devices are used for measurements
specified in the various parts of ISO 11451 and ISO 11452.
The scope and field of application are further detailed in clause 1 (see page 9) of the enclosed IEEE standard.
2 Requirements
For the purposes of international standardization, the following provisions shall apply to the specific clauses
and paragraphs of IEEE std 1309-1996.
Pages i to iv (reproduced here as pages 3 to 6)
This is information relevant to the IEEE publication only.
Page 68
Add the following information to Annex J.
[1] ISO 11451 (all parts), Road vehicles — Vehicle test methods for electrical disturbances from
narrowband radiated electromagnetic energy
[2] ISO 11452 (all parts), Road vehicles — Component test methods for electrical disturbances from
narrowband radiated electromagnetic energy
[3] DIN VDE 0847, Methods of measurement for the electromagnetic compatibility — Part 26: Calibration
of field measuring receivers for EMC and personal safety applications for frequencies > 0 Hz
[4] NBSIR 75-804, Generation of Standard EM fields for Calibration of Power Density Meters 20 kHz to
1 000 MHz
3 Revision of publication IEEE 1309-1996
It has been agreed with IEEE that ISO/TC 22, Road vehicles, Subcommittee SC 3, Electrical and electronic
equipment, will be consulted in the event of any revision or amendment of IEEE std 1309-1996. To this end,
ANSI, the American National Standards Institute, will act as liaison between IEEE and ISO.
IEEE Std 1309-1996
IEEE Standard for Calibration of
Electromagnetic Field Sensors and
Probes, Excluding Antennas, from
9 kHz to 40 GHz
Sponsor
IEEE Electromagnetic Compatibility Society
Approved 20 June 1996
IEEE Standards Board
Abstract: Consensus calibration methods for electromagnetic field sensors and field probes are
provided. Data recording and reporting requirements are given, and a method for determining
uncertainty is specified.
Keywords: calibration, electromagnetic, field probe, field sensor, probe antenna
The Institute of Electrical and Electronics Engineers, Inc.
345 East 47th Street, New York, NY 10017-2394, USA
Copyright © 1996 by the Institute of Electrical and Electronics Engineers, Inc.
All rights reserved. Published 1996. Printed in the United States of America.
ISBN 1-55937-767-4
No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without the prior
written permission of the publisher.
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ing Committees of the IEEE Standards Board. Members of the committees serve voluntarily and
without compensation. They are not necessarily members of the Institute. The standards developed
within IEEE represent a consensus of the broad expertise on the subject within the Institute as well
as those activities outside of IEEE that have expressed an interest in participating in the develop-
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Use of an IEEE Standard is wholly voluntary. The existence of an IEEE Standard does not imply
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time a standard is approved and issued is subject to change brought about through developments in
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4 © ISO 2003 — All rights reserved

Introduction
(This introduction is not part of IEEE Std 1309-1996, IEEE Standard Method for the Calibration of Electromagnetic
Field Sensors and Field Probes, Excluding Antennas, from 9 kHz to 40 GHz.)
This standard was prepared by the Working Group on Methods for Calibration of Field Sensors and Field
Probes, Excluding Antennas, from 9 kHz to 40 GHz, and is sponsored by the Electromagnetic Compatibility
Society.
The following is a list of committee members and signiÞcant contributors.
John Kraemer, Chair Luc D. Troung, Vice Chair
Charles R. Haight, Secretary
Poul H. Anderson Tim DÕArcangelis Motohisa Kanda
Edward Aslan Paul Ewing Tom Karas
David Baron Harry Gaul Galen Koepke
Edwin L. Bronaugh Tim Harrington Richard Rogers
David L. Brumbaugh Robert D. Hunter Paul A. Sikora
Dennis Camell Robert Johnk Gary Sower
The following persons were on the balloting committee:
Poul H. Anderson Charles R. Haight James C. Parker, Jr.
Edward Aslan Donald N. Heirman Risaburo Sato
David Baron Daniel D. Hoolihan Ralph M. Showers
H. Stephen Berger Robert D. Hunter Paul A. Sikora
Edwin L. Bronaugh Motohisa Kanda Gary Sower
David L. Brumbaugh Galen Koepke David Staggs
Joseph E. Butler John G. Kraemer David L. Traver
Hugh W. Denny John D. Osburn Luc D. Troung
When the IEEE Standards Board approved this standard on 20 June 1996, it had the following membership:
Donald C. Loughry, Chair Richard J. Holleman, Vice Chair
Andrew G. Salem, Secretary
Ben C. Johnson Arthur K. Reilly
Gilles A. Baril
E. G. ÒAlÓ Kiener Ronald H. Reimer
Clyde R. Camp
Joseph L. KoepÞnger* Gary S. Robinson
Joseph A. Cannatelli
Lawrence V. McCall Ingo RŸsch
Stephen L. Diamond
L. Bruce McClung John S. Ryan
Harold E. Epstein
Marco W. Migliaro Chee Kiow Tan
Donald C. Fleckenstein
Jay Forster* Mary Lou Padgett Leonard L. Tripp
Donald N. Heirman John W. Pope Howard L. Wolfman
Jose R. Ramos
*Member Emeritus
Also included are the following nonvoting IEEE Standards Board liaisons:
Satish K. Aggarwal
Alan H. Cookson
Chester C. Taylor
Lisa S. Young
IEEE Standards Project Editor
6 © ISO 2003 — All rights reserved

Contents
CLAUSE PAGE
1. Overview. 9
1.1 Scope. 9
1.2 Purpose. 10
1.3 Background. 10
1.4 Grades of Calibration. 10
1.5 Generic Probe Types. 10
2. References. 11
3. Definitions. 12
4. Measurement methods . 13
4.1 Methods. 13
4.2 Field sensor or field probe orientation during frequency domain calibration . 14
4.3 Field probe or field sensor orientation during time domain calibration . 15
5. Standard field generation methods. 16
5.1 Frequency domain field generation . 16
5.2 Time domain field generation. 17
6. Determining uncertainty . 17
6.1 Standard uncertainty . 17
6.2 Combined standard uncertainty . 17
6.3 Expanded uncertainty. 18
6.4 Reporting uncertainty. 18
7. Characteristics to be measured. 18
7.1 Frequency domain calibration. 18
7.2 Time domain calibration. 21
8. Procedures (measurement techniques). 22
8.1 Transfer standard sensors and probes . 22
8.2 Transfer and working standard sensors and probes . 22
8.3 Frequency domain calibration procedure. 23
8.4 Time domain calibration procedure. 26
9. Documentation. 27
9.1 Proper documentation . 27
9.2 Test documentation. 27
9.3 Calibration interval . 28
9.4 Out-of-tolerance notification . 28
9.5 Certification to customer. 28
ANNEX PAGE
Annex A (normative) Grades of calibrations . 29
A.1 Grades of calibration. 29
A.2 Grades of calibration notation summary. 32
A.3 Cautions and examples . 32
Annex B (normative) methods of field generation and field calculations . 34
B.1 Electric and magnetic field generation using a TEM cell, 9 kHzÐ500 MHz. 34
B.2 Magnetic field generation using Helmholtz coils, 9 kHz to 10 MHz . 37
B.3 Open-ended waveguide source in anechoic chamber, 200Ð450 MHz. 44
B.4 Pyramidal horn antenna source in an anechoic chamber, 450 MHzÐ40 GHz . 46
B.5 Waveguide chamber, 100 MHz to 2.6 GHz. 49
B.6 Gigahertz TEM (GTEM) cell, 9 kHz to 1 GHz . 50
B.7 Parallel plate transmission line . 51
B.8 Conical transmission line. 53
B.9 Cone and ground plane . 53
Annex C (informative) Field sensor and field probe calibration factors. 55
C.1 Cables. 56
C.2 Other . 57
Annex D (informative) Types of measurements . 57
Annex E (informative) Time domain versus frequency domain measurements. 58
Annex F (informative) Deconvolution . 59
Annex G (informative) Burst peak measurement. 61
Annex H (informative) Examples on determining uncertainty . 63
H.1 Standard uncertainty . 64
H.2 Combined standard uncertainty . 64
H.3 Expanded uncertainty. 64
H.4  Reporting uncertainty. 65
Annex I (informative) Time domain pulse fidelity. 66
Annex J (informative) Bibliography . 68
8 © ISO 2003 — All rights reserved

IEEE Standard for the Calibration of
Electromagnetic Field Sensors and
Field Probes, Excluding Antennas,
from 9 kHz to 40 GHz
1. Overview
1.1 Scope
This standard provides calibration methods for electromagnetic (EM) Þeld sensors and Þeld probes,
excluding antennas per se, for the frequency range of 9 kHz to 40 GHz. Field injection probe (transmitting)
calibration is not covered by this standard. This standard is not applicable to EMI emission measurement
antennas, such as active and passive whip antennas, used in the general frequency range of 9 kHz to 30 MHz.
This standard also provides alternative calibration methods that are appropriate to various frequency ranges
and various user requirements. These methods are applicable to any (active, passive, photonic, etc.) Þeld sen-
sor or Þeld probe. Methods are provided for frequency domain and time (transient) domain calibration.
Methods for creating standard electric and magnetic Þelds are described in clause 5. Each method has known
calculated Þeld strength and associated errors. Each standard Þeld method is individually addressed. The
Þeld generation information was obtained from IEEE Std 291-1991 and from IEEE Std C95.3-1991, with
additional information from sources listed in the bibliography.
Most electromagnetic Þeld measurements are made in the frequency domain, either at a single frequency or
at a number of frequencies. The ever-increasing susceptibility of electronic circuits has awakened interest in
transient electromagnetic phenomena such as electrostatic discharge (ESD), electromagnetic pulse (EMP),
and system-generated transients, such as automotive ignition noise. The measurement of these transient
Þelds requires electromagnetic Þeld probes and sensors that can faithfully replicate the transient wave-
shapes, thus requiring an equivalent bandwidth of decades. The calibration of time domain sensors necessi-
tates procedures that are signiÞcantly different than those for the frequency domain sensors.
The electric or magnetic Þeld sensor and/or Þeld probe calibration requirements depend on the design and
the manufacturerÕs speciÞcations. The calibration shall address the amplitude response, frequency response,
accuracy (uncertainty), linearity, and isotropy. Additionally the calibration may address response time, time
constant, and response to signal modulation.
Information on references can be found in clause 2.
IEEE
Std 1309-1996 IEEE STANDARD FOR CALIBRATION OF ELECTROMAGNETIC FIELD SENSORS
1.2 Purpose
This standard provides consensus calibration methods for electromagnetic Þeld sensors and Þeld probes.
Calibration organizations and others need uniform calibration methods to obtain consistent results. The
calibration methods of this standard will produce results readily traceable to a national standards authority
such as the National Institute of Standards and Technology (NIST) in the United States.
1.3 Background
Antenna calibration is the subject of existing standards, such as ANSI C63.5-1988. Though Þeld sensors and
Þeld probes are in a broad sense antennas, the uses of antennas, Þeld sensors, and Þeld probes are different.
Antennas are designed to transmit or receive with maximum coupling to the electromagnetic Þeld, thus they
perturb the electromagnetic Þeld. Field sensors and Þeld probes are designed to measure an electromagnetic
Þeld with minimal perturbation.
There is agreement on antenna calibration methods. Attempts to apply antenna calibration methods to Þeld
sensors and Þeld probes have resulted in inconsistent results between calibration organizations and others.
This standard is intended to provide consistent methods and results for different calibration services.
1.4 Grades of calibration
The extent to which a Þeld probe or Þeld sensor is calibrated and characterized depends on its intended use
and the degree of detail required by the user. However, for each characteristic measured, the calibration
method and speciÞc test points measured (if applicable) and a statement of uncertainty (error) shall be
provided to the user. Applicable characteristics of the calibration include, but are not limited to, the following:
Ñ Method of calibration
Ñ Type of calibration (time domain or frequency domain)
Ñ Amplitude level(s) measured
Ñ Frequencies measured
Ñ Response time
Ñ Time constant
Ñ Modulation response
Ñ Isotropy
Ñ Uncertainty
1.5 Generic Probe Types
Field probes and sensors are grouped into one of two categories based on the location of the Þeld measured
with respect to the ground plane. This standard thus deÞnes Þeld probes and sensors as either being Ôground
planeÕ or Ôfree Þeld.Õ Detailed deÞnitions are presented in clause 3 of this standard. SpeciÞc calibration
instrumentation, procedures, and Þeld generation methods may be different between these two groups of
probes and sensors. This standard is applicable to both types of Þeld probes and Þeld sensors; the free Þeld
probes and sensors being placed in a Þeld that completely surrounds them, and the ground plane Þeld probes
and sensors being mounted on the ground plane with respect to the Þeld source.
There are two differences between time derivative (B-dot and D-dot) sensors and direct Þeld reading (E-Field
and H-Field) sensors. Traditionally, the Þrst difference is that E-Þeld sensors are the Thevenin equivalent cir-
cuit for an electrically small electric dipole, while the D-dot sensor is the Norton equivalent circuit. Similarly,
the H-Field sensor is the Norton equivalent circuit for an electrically small electric dipole, while the B-dot
sensor is the Thevenin equivalent circuit. The second difference is that the constitutive parameters e and µ
10 © ISO 2003 — All rights reserved

IEEE
AND PROBES, EXCLUDING ANTENNAS, FROM 9 kHz TO 40 GHz Std 1309-1996
Table 1ÑGeneric EM Þeld probes and sensors
Free Þeld Ground plane Þeld
E-Field (dipole) E-Field (monopole )
H-Field (loop) H-Field (half-loop)
D-dot D-dot
B-dot B-dot
relating the electric and magnetic Þeld quantities are, in general, not linear, time invariant, or isotropic; if they
were, then MaxwellÕs equations would contain only two parameters instead of four. These constitutive
parameters are tensor quantities that can change with time and Þeld strength, and do indeed exhibit these non-
constant properties in certain situations in which the sensors have been used (for example, in nuclear source
regions). A more detailed explanation is contained in [B9] .
This standard also applies to Þeld probes that indicate power density; it is realized that the response of these
Þeld probes is based on the strength of an E-Field or H-Field and that far-Þeld conditions are assumed.
.
CAUTION
Depending upon the Þeld strengths, frequency ranges, and other factors, the Þeld intensities required to cal-
ibrate E-Þeld and H-Þeld probes may be hazardous. The user of this standard is advised to observe all
appropriate safety measures for nonionizing radiation. See IEEE Std C95.1-1991, IEEE Std C95.3-1991,
and the references cited in these documents, as well as other appropriate documents.
2. References
This standard shall be used in conjunction with the following publications.
ANSI C63.5-1988, Electromagnetic CompatibilityÑRadiated Emission Measurements in Electromagnetic
Interference (EMI) ControlÑCalibration of Antennas.
ANSI C63.14-1992, Dictionary for Technologies of Electromagnetic Compatibility (EMC), Electromagnetic
Pulse (EMP), and Electrostatics Discharge (ESD).
ANSI Z540-1-1994, CalibrationÑCalibration Laboratories and Measuring and Test EquipmentÑGeneral
Requirements.
IEEE Std 100-1992, The New IEEE Standard Dictionary of Electrical and Electronics Terms (ANSI).
IEEE Std 291-1991, IEEE Standard Methods for Measuring Electromagnetic Field Strength of Sinusoidal
Continuous Waves, 30 Hz to 30 GHz (ANSI).
The numbers in brackets preceded by the letter B correspond to those of the bibliography in annex J.
ANSI publications are available from the Sales Department, American National Standards Institute, 11 West 42nd Street, 13th Floor,
New York, NY 10036, USA.
IEEE publications are available from the Institute of Electrical and Electronics Engineers, 445 Hoes Lane, P.O. Box 1331, Piscataway,
NJ 08855-1331, USA.
IEEE
Std 1309-1996 IEEE STANDARD FOR CALIBRATION OF ELECTROMAGNETIC FIELD SENSORS
IEEE Std C95.1-1991, IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Fre-
quency Electromagnetic Fields, 3 kHz to 300 GHz (ANSI).
IEEE Std C95.3-1991, IEEE Recommended Practice for the Measurement of Potentially Hazardous
Electromagnetic FieldsÑRF and Microwave (ANSI).
ISO/IEC Guide to the Expression of Uncertainty in Measurement (1995).
National Conference of Standards Laboratories (NCSL) RP-12, Recommended Practice for Determining
and Reporting Measurement Uncertainties, 1 Feb. 1994.
NIST Handbook 150, National Voluntary Laboratory Accreditation Program, Procedures and General
Requirements.
3. DeÞnitions
This clause contains only those deÞnitions relating to Þeld sensor and Þeld probe calibration that are not
listed in IEEE Std 100-1992 or in ANSI C63.14-1992.
3.1 antenna: A device used for transmitting or receiving electromagnetic signals or power. It is designed to
maximize its coupling to the electromagnetic Þeld; as a receiver, it is made to intercept as much of the Þeld
as possible. Those devices that are made to measure the power level of the electromagnetic Þeld rather than
its Þeld components are included in this category.
3.2 Þeld probe: An electrically small Þeld sensor or set of multiple Þeld sensors with various electronics (for
example, diodes, resistors, ampliÞers, etc.). The output from a Þeld probe cannot be theoretically determined
from easily measured physical parameters.
3.3 Þeld sensor: An electrically small device without electronics (passive) that is used for measuring electric
or magnetic Þelds, with a minimum of perturbation to Þeld being measured. The Þeld sensor transfer func-
tion (ratio of output signal-to-input electromagnetic Þeld) can be theoretically determined from measured
physical (geometrical) properties, such as length, radius, area, etc., as well as the electrical characteristics of
the construction material. The measured physical properties must be traceable to internationally accepted
standards via a national standards authority (for example, the NIST in the U.S.).
3.4 free Þeld: The electromagnetic Þeld in a volume far removed from physical objects, conductive or non-
conductive; it is usually thought of, but not restricted to, a plane wave. For the case of a plane wave, the elec-
trical and magnetic vectors are transverse to the propagation vector and to each other [transverse
electromagnetic mode (TEM)], and their ratio yields the intrinsic impedance of free space. Syn: free space
Þeld.
3.5 free space Þeld: See: free Þeld.
3.6 frequency domain calibration: A result that is the transfer function of the sensor or probe. A continu-
ous wave calibration is a transfer function at a single frequency.
3.7 ground plane Þeld: The electromagnetic Þeld in near proximity to a conducting surface, with the
boundary conditions that the tangential electric Þeld approach zero and the normal magnetic remain
continuous. The total normal electric Þeld is related to the surface charge density by GaussÕ law, and the total
tangential magnetic Þeld to the surface current density by AmpereÕs law.
ISO publications are available from the ISO Central Secretariat, Case Postale 56, 1 rue de VarembŽ, CH-1211, Genve 20, Switzer-
land/Suisse. ISO publications are also available in the United States from the Sales Department, American National Standards Institute,
11 West 42nd Street, 13th Floor, New York, NY 10036, USA.
NCSL publications are available from the National Conference of Standards Laboratories, 1800 30th Street, Suite 305B, Boulder, CO
80301-1032, USA.
NIST publications are available from the National Institute of Standards and Technology Library, Gaithersburg, MD 20899, USA.
12 © ISO 2003 — All rights reserved

IEEE
AND PROBES, EXCLUDING ANTENNAS, FROM 9 kHz TO 40 GHz Std 1309-1996
3.8 ortho-axis: An angle of 54.7 ¼ to the edges and centerlines of each face of the device under test (DUT).
This angle is the ortho-angle that is the angle that the diagonal of a cube makes to each side at the trihedral
corners of the cube [B14] (see Þgure 5 in 8.3.2.2).
3.9 response time: The time required for a Þeld probe to reach 90% of its steady state value when the Þeld is
applied as a step function. The measurement includes test setup response time, thus giving worst case
results.
3.10 time constant: The time required for a Þeld probe output to reach a stable, repeatable reading. The
measurement includes test setup, metering unit, cables, etc., thus is a worst case result. The measurements
assume an exponential response of the Þeld probe. The time constant is used speciÞcally for burst peak Þeld
strength measurements.
3.11 time domain calibration: A result that is the impulse response function of the sensor or probe in the
time domain.
3.12 transfer function: The ratio of the device output signal (voltage, current, frequency, meter reading,
etc.) to the incident Þeld or Þeld vector of interest in the frequency domain. The transfer function is the
Laplace (or Fourier) transform of the impulse response function.
3.13 transfer standard: An electrically small Þeld probe or Þeld sensor. This can be a short dipole for sens-
ing E-Þelds or a small loop for H-Þelds, which has a known response over a given range of frequency and
amplitude. This known response can be either accurately calculable quasi-static response parameters or a
calibration performed to some speciÞed accuracy and precision by an accredited calibration facility.
4. Measurement methods
4.1 Methods
This standard provides three calibration methods, but does not endorse any as a preferred method. The cali-
bration organization may use any method listed and deÞned in table 2 to calibrate Þeld sensors and Þeld
probes. However, calibration, as deÞned by this standard, requires the results to be accompanied by a
description of the method used and by quantitative statements of uncertainty, as described in clause 6.
Table 2ÑThree calibration methods
Method Description
Calibration using the Transfer Standard (a Þeld sensor or Þeld probe similar to the
one being calibrated), that has traceability to a national standards laboratory, such as
A
NIST in the U.S. The Transfer Standard is used to measure and calibrate the Þeld
used for calibrating the Þeld sensor of Þeld probe under test.
Calibration using Calculated Field Strengths. The Unit Under Calibration is placed
B in a calculated reference Þeld based on the geometry of the Þeld source and the Þeld
source measured input parameters.
Calibration using a Primary Standard (Reference) Sensor, that contains no active or
passive electronic devices and has its calibration traceable to a national standards
C
laboratory based on international standards. It is used to determine the Þeld strength
used to calibrate the Unit Under Calibration.
It should be noted that method C, and its resulting uncertainty, is only applicable to the Þeld sensor
calibrated and thus does not address uncertainty resulting from the characteristics of connectors, cables, and/
or environmental disturbances and the like, that may add additional uncertainty in actual use.
IEEE
Std 1309-1996 IEEE STANDARD FOR CALIBRATION OF ELECTROMAGNETIC FIELD SENSORS
4.2 Field sensor or Þeld probe orientation during frequency domain calibration
4.2.1 Directional and positional effects
As part of the calibration, it is necessary to identify directional and positional effects on the measured level
of the Þeld intercepted. In addition, if so equipped and intended for use in normal operation, accessories to
the Þeld sensor and Þeld probe, such as cable or metering module, shall be veriÞed as not affecting the valid-
ity of the calibration. The accuracy may be affected by Þeld perturbation, losses in the accessory (cables,
metering modules,) etc.; each shall be checked for having directional and positional effects and accuracy
effects on the measurement being made.
4.2.2 Calibration data collection
Calibration data shall be collected and reported, as a minimum, at the following Þeld sensor (or Þeld probe)
alignment positions as indicated by the isotropy grade selected (see table A.4). It shall be noted, that in all
cases, if there is a choice, the end of the Þeld sensor (or Þeld probe) containing the element(s) intercepting
the applied Þeld, is to be closest to the Þeld source.
4.2.2.1 Maximum interception alignment
Each independent Þeld sensor or Þeld probe element shall be aligned for maximum interception of the
applied Þeld vector. For Þeld sensors and Þeld probes using dipoles for Þeld interception, the dipole shall be
considered the independent element. This alignment provides data on the base contribution of each Þeld sen-
sor or Þeld probe independent element to the overall Þeld measurement. The alignment also provides perfor-
mance characteristics of each Þeld sensor or Þeld probe element.
Figure 1ÑMaximum interception alignment
4.2.2.2 Physical major axis
The Þeld sensor or Þeld probe physical major axis is to be positioned perpendicular to the applied Þeld vec-
tor. If the Þeld sensor or Þeld probe does not have a physical major axis, an orientation shall be selected and
documented that reßects the positioning expected during normal use.
Once the Þeld sensor or Þeld probe is positioned and a Þeld is established, the Þeld sensor or Þeld probe is
rotated 360 ¡ around the physical major axis. The maximum measured Þeld value, minimum measured Þeld
value, and the sensor orientation with respect to the incident Þeld are to be recorded.
4.2.2.3 Physical minor axis
The Þeld sensor or Þeld probe physical minor axis is to be positioned so as to be perpendicular to the applied
Þeld vector. If the Þeld sensor or Þeld probe does not have a physical minor axis, an orientation shall be
14 © ISO 2003 — All rights reserved

IEEE
AND PROBES, EXCLUDING ANTENNAS, FROM 9 kHz TO 40 GHz Std 1309-1996
Figure 2ÑPhysical major axis alignment
selected and documented that reßects the positioning expected during normal use. This orientation must be
perpendicular to the one selected in 4.2.2.2 of this standard.
Once the Þeld sensor or Þeld probe is positioned and a Þeld is established, the Þeld sensor or Þeld probe is
rotated 360 ¡ around the physical minor axis. The maximum measured Þeld value, minimum measured Þeld
value, and the sensor orientation with respect to the incident Þeld are to be recorded.
Figure 3ÑPhysical minor axis alignment
4.3 Field probe or Þeld sensor orientation during time domain calibration
For calibration purposes, the orientation of a particular time-domain Þeld sensor depends on how it is going
to be actually deployed. Given the wide variety of time-domain Þeld sensor types, structural geometry, and
the multitude of Þeld sensor applications, there is not a Þxed method for orientating a Þeld probe for
calibration. However, in many instances, the following calibration guidelines are quite useful.
a) Usually information is sought about one or more vector components of the following four Þeld
quantities: the electric Þeld intensity E, the electric ßux density D, the magnetic ßux density B, and
the magnetic intensity Þeld H [B29]. Different sensors have been developed and optimized to mea-
sure the various Þeld quantities [B9]. In most sensor applications, information about a particular
electromagnetic Þeld component (its time derivative or some other linear operation(s) with respect to
time) is of interest. Only in rare instances is information needed about all of the Þeld components for
a given measurement.
b) For a Þeld sensor calibration to be of maximum value, the calibration of a sensor should be per-
formed in a manner that most closely simulates
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