IEC 62577:2009

IEC 62577 ®
Edition 1.0 2009-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Evaluation of human exposure to electromagnetic fields from a stand-alone
broadcast transmitter (30 MHz – 40 GHz)

Evaluation de l'exposition des personnes aux champs électromagnétiques
provenant des émetteurs de radiodiffusion isolés (30 MHz – 40 GHz)

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IEC 62577 ®
Edition 1.0 2009-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Evaluation of human exposure to electromagnetic fields from a stand-alone
broadcast transmitter (30 MHz – 40 GHz)

Evaluation de l'exposition des personnes aux champs électromagnétiques
provenant des émetteurs de radiodiffusion isolés (30 MHz – 40 GHz)

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
T
CODE PRIX
ICS 13.280; 17.240; 33.170 ISBN 978-2-88910-767-4
– 2 – 62577 © IEC:2009
CONTENTS
FOREWORD.3
1 Scope and object.5
2 Normative references .5
3 Terms and definitions .5
4 Physical quantities, units and constants .9
4.1 Quantities.9
4.2 Constants.10
5 Applicability of compliance assessment methods.10
5.1 Overview .10
5.2 Assessment procedure .10
5.3 Representative antennas for each service .11
6 SAR measurement and calculation .12
6.1 Whole-body SAR inherent compliance.12
6.2 SAR compliance.12
7 Electromagnetic field measurement .12
7.1 Measurement .12
7.2 Measurement uncertainty .13
8 Electromagnetic field calculation .16
8.1 Procedures to calculate the electromagnetic field .16
8.2 Field regions .17
8.3 Calculation models .18
9 Contact currents measurement and calculation.19
10 Induced current measurement and calculation .19
Annex A (normative) Field measurement in a volume surrounding the EUT.20
Annex B (informative) Compliance boundary examples.23
Bibliography.25

Figure 1 – Alternative routes to calculate E-field, H-field values at point of investigation.17
Figure A.1 – Block diagram of the EUT measurement system .20
Figure A.2 – Cylindrical, cartesian and spherical co-ordinates defined relative to the
EUT .21

Table 1 – Applicable methods for each antenna region .11
Table 2 – Representative antennas.12
Table 3 – Recommended parameters.13
Table 4 – Uncertainty evaluation.16
Table B.1 – Compliance boundary examples.24

62577 © IEC:2009 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
EVALUATION OF HUMAN EXPOSURE TO ELECTROMAGNETIC FIELDS
FROM A STAND-ALONE BROADCAST TRANSMITTER
(30 MHz – 40 GHz)
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62577 has been prepared by IEC technical committee 106:
Methods for the assessment of electric, magnetic and electromagnetic fields associated with
human exposure, and CENELEC TC 106X: Electromagnetic fields in the human environment.
The text of this standard is based on the following documents:
FDIS Report on voting
106/176/FDIS 106/179/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 4 – 62577 © IEC:2009
The committee has decided that the contents of this 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.
IMPORTANT – The “colour inside” logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this publication using a colour printer.

62577 © IEC:2009 – 5 –
EVALUATION OF HUMAN EXPOSURE TO ELECTROMAGNETIC FIELDS
FROM A STAND-ALONE BROADCAST TRANSMITTER
(30 MHz – 40 GHz)
1 Scope and object
This International Standard applies to a single stand-alone broadcast transmitter operating in
the frequency range 30 MHz to 40 GHz when put on the market (see Note 1).
The objective of the standard is to specify, for such equipment operating in typical conditions,
the method for assessment of compliance distances according to the basic restrictions
(directly or indirectly via compliance with reference levels) related to human exposure to radio
frequency electromagnetic fields.
NOTE 1 This standard only applies to broadcast transmitters being placed on the market (type approval) and
does not apply to broadcast transmitters being commissioned or placed into service.
NOTE 2 Compliance certification depends on the policy of national regulatory bodies.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
ISO/IEC Guide 98-3:2008, Uncertainty of measurement – Part 3: Guide to the expression of
uncertainty in measurement (GUM:1995))
EN 50413, Basic standard on measurement and calculation procedures for human exposure
to electric, magnetic and electromagnetic fields (0 Hz – 300 GHz)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
antenna
device that serves as a transducer between a guided wave (e.g. coaxial cable) and a free
space wave, or vice versa
3.2
basic restriction
restrictions on exposure to time-varying electric, magnetic, and electromagnetic fields that are
based directly on established health effects
3.3
broadcasting service
radiocommunication service in which the transmissions are intended for direct reception by
the general public. This service may include sound transmissions, television transmissions or
other types of transmission
– 6 – 62577 © IEC:2009
3.4
compliance distance
minimum distance from the antenna where a point of investigation is deemed to be compliant.
The set of compliance distances therefore defines the boundary outside which the exposure
levels do not exceed the basic restrictions irrespective of the time of exposure. The distances
are measured related to the nearest point of the antenna in each investigation direction
3.5
conductivity
σ
ratio of the conduction-current density in a medium to the electric field strength. Conductivity
is expressed in units of siemens per metre (S/m)
3.6
contact current
current produced in the body involved by human contact with metallic objects in the field.
Shocks and burns can be the adverse indirect effects. Contact current relates to an
instantaneous effect and so can't be time-averaged
3.7
electric field strength
E
magnitude of a field vector at a point that represents the force (F) on a positive small charge
(q) divided by the charge
F
E = (1)
q
Electric field strength is expressed in units of volt per metre (V/m).
3.8
electric flux density
D
magnitude of a field vector that is equal to the electric field strength (E) multiplied by the
permittivity ( ε )
D = εE (2)
Electric flux density is expressed in units of coulomb per square metre (C/m²).
NOTE See also IEV 121-11-40.
3.9
equipment under test
EUT
device (such as transmitter, or antenna as appropriate) that is the subject of the specific test
investigation being described
3.10
induced current
currents circulating inside a human body resulting directly from an exposure to an
electromagnetic field
62577 © IEC:2009 – 7 –
3.11
intrinsic impedance (of free space η )
η
ratio of the electric field strength to the magnetic field strength of a propagating
electromagnetic wave. The intrinsic impedance of a plane wave in free space is 120 π
(approximately 377 Ω)
3.12
isotropic radiator
a hypothetical antenna, without loss, having equal radiation intensities in all directions and
serving as a convenient reference for expressing the directional properties of actual antennas
NOTE Deviations of isotropy have to be considered at all measured values of EMF with regard to various angles
of incidence and polarization of the measured field. In this document it is defined for incidences covering a
hemisphere centred at the tip of the probe, with an equatorial plane normal to the probe and expanding outside the
probe. The axial isotropy is defined by the maximum deviation of the measured quantity when rotating the probe
along its main axis with the probe exposed to a reference wave with normal incidence with regard to the axis of the
probe. The hemispherical isotropy is defined by the maximum deviation of the measured quantity when rotating the
probe along its main axis with the probe exposed to a reference wave with varying angles of incidences and
polarisation with regard to the axis of the probe in the half space in front of the probe.
3.13
linearity
when all relationships between a reference quantity and the deviations of this quantity lie along a
straight line (e.g. of an antenna or any other technical device). The maximum deviation over the
measurement range of the measured quantity value from the closest linear reference curve defined
over a given interval should be taken into account in measurement procedures
3.14
magnetic field strength
H
magnitude of a field vector in a point that results in a force ( ) on a charge q moving with the
F
velocity
v
F = q()ν × μH (3)
The magnetic field strength is expressed in units of ampere per metre (A/m).
3.15
magnetic flux density
B
magnitude of a field vector that is equal to the magnetic field strength H multiplied by the
permeability (μ) of the medium
B = μ Η (4)
Magnetic flux density is expressed in units of tesla (T).
3.16
modulation
process, or the result of the process, where some characteristic of the wave (amplitude,
frequency or phase) is varied in accordance with another wave or signal. It must also be taken
into consideration when carrying out measurements and calculations to determine whether or
not the limits are being exceeded

– 8 – 62577 © IEC:2009
3.17
permeability
μ
magnetic permeability of a material defined by the magnetic flux density B divided by the
magnetic field strength H:
B
μ = (5)
H
where
μ is the permeability of the medium expressed in henry per metre (H/m).
3.18
permittivity
ε
property of a dielectric material (e.g., biological tissue) defined by the electrical flux density D
divided by the electrical field strength E
D
ε = (6)
E
The permittivity is expressed in units of farad per metre (F/m).
3.19
point of investigation
PI
E-field, H-field, power flux density or SAR is evaluated.
location in space at which the value of
This location is defined in cartesian, cylindrical or spherical co-ordinates relative to the
reference point on the EUT
3.20
power density
S
radiant power incident perpendicular to a surface, divided by the area of the surface. The
power density is expressed in units of watt per square metre (W/m²)
3.21
reference levels
reference levels of exposure are provided for comparison with measured values of physical
quantities
NOTE 1 Compliance with all reference levels given in these guidelines will ensure compliance with basic
restrictions. If measured values are higher than reference levels, it does not necessarily follow that the basic
restrictions have been exceeded, but a more detailed analysis is necessary to assess compliance with the basic
restrictions.
NOTE 2 In the frequency range 30 MHz to 40 GHz the reference levels are expressed as electric field strength,
magnetic field strength, power density values and contact currents.
3.22
relative permittivity
ε
r
ratio of the permittivity of a dielectric material to the permittivity of free space i.e.:
ε
ε = (7)
r
ε
62577 © IEC:2009 – 9 –
3.23
root-mean-square
r.m.s.
value obtained by taking the square root of the average of the square of the value of the
periodic function taken throughout one period. See also IEV 101-14-15.
3.24
specific absorption rate
SAR
time derivative of the incremental energy (dW) absorbed by (dissipated in) an incremental
mass (dm) contained in a volume element (dV) of given mass density (ρ )
d ⎛ dW ⎞ d ⎛ dW ⎞
SAR = = ⎜ ⎟ (8)
⎜ ⎟
⎜ ⎟
dt dm dt ρdV
⎝ ⎠ ⎝ ⎠
SAR is expressed in units of watt per kilogram (W/kg).
NOTE SAR can be calculated by:
σ E
i
SAR = (9)
ρ
where
E is the r.m.s. value of the electric field strength in the tissue in V/m;
i
σ is the conductivity of body tissue in S/m;
ρ is the density of body tissue in kg/m³.
3.25
transmitter
device to generate radio frequency power for the purpose of communication but on its own is
not intended to radiate it
4 Physical quantities, units and constants
4.1 Quantities
The internationally accepted SI-units are used throughout the standard.
Quantity Symbol Unit Dimensions
Current density J ampere per square metre
A/m²
E
Electric field strength volt per metre V/m
Electric flux density D coulomb per square metre
C/m²
Electric conductivity siemens per metre S/m
σ
Frequency f hertz Hz
Magnetic field strength H ampere per metre A/m
Magnetic flux density B T
tesla (Vs/m²)
Mass density kilo per cubic metre
ρ kg/m³
Permeability henry per metre H/m
μ
Permittivity farad per metre F/m
ε
Specific absorption rate SAR watt per kilogram W/kg
Wavelength metre m
λ
T
Temperature kelvin K
– 10 – 62577 © IEC:2009
4.2 Constants
Physical constant Magnitude
Speed of light in a vacuum c
2,997 × 10 m/s
-12
Permittivity of free space
ε 8,854 × 10 F/m
-7
Permeability of free space
μ
4 π × 10 H/m
Impedance of free space
120 π (approx. 377) Ω
η
5 Applicability of compliance assessment methods
5.1 Overview
Guidelines and recommended limits on human exposure to radio waves give basic restrictions
in terms of SAR or power flux density and also reference levels in terms of contact current
and field strengths or power density.
The compliance boundary defines the volume outside which the exposure levels do not
exceed the basic restrictions irrespective of the time of exposure for the specific operating
conditions of the broadcast transmitter. The compliance boundary is determined via a
procedure where sufficient points of investigation are assessed.
It is technically possible to determine the compliance distance through measurements or
calculations of SAR or electromagnetic fields relating to basic restrictions or reference levels,
since compliance to the reference levels guarantees compliance to the basic restrictions.
Where the assessment is made through SAR, it should be noted that both localised and
whole-body basic restrictions must be considered. Spatial averaging may be used with field
strength assessments in order to assess whole-body SAR.
5.2 Assessment procedure
5.2.1 Methods
This standard describes measurement and calculation methods that may be used to establish
the compliance distances (see Table 1).

62577 © IEC:2009 – 11 –
Table 1 – Applicable methods for each antenna region
a to c
Applicable methods for each antenna region

Reactive near-field Radiating near-field Far-field
Basic restriction
b
SAR or power density evaluation (calculation or measurement) – Clause 6
evaluation
Reference level E-field and H-field calculation E-field or H-field calculation E-field or H-field calculation –
c
calculation Clause 8 Clause 7 Clause 8
Induced currents calculation Induced current calculation

Clause 10 Clause 10
Reference level E-field and H-field E-field or H-field measurement E-field or H-field measurement

c c
measurement measurement
Clause 7 Clause 7
c
Clause 7
Induced currents measurement Induced currents measurement

Induced currents measurement Clause 10 Clause 10

Clause 10
a
Compliance with the reference level will ensure compliance with the relevant basic restriction. If the measured or
calculated value exceeds the reference level, it does not necessarily follow that the basic restriction will be
exceeded. However, whenever a reference level is exceeded, it is necessary to test compliance with the relevant
basic restriction and to determine whether additional protective measures are necessary.
b
SAR calculation is the reference, since it takes into account the fine structure of the head/body.
c
Due to the existing probes on the market, above 2,5 GHz, only the E-field is measured and calculation on H level
has to be performed.
5.2.2 Compliance distances
The distances are measured related to the nearest point of the antenna in each investigation
direction. The boundary of all compliance distances may have a complex shape. It may be
simplified by a simple boundary (e.g. sphere or cylinder) provided any points of investigation
outside the compliance boundary shall be in compliance with the limits. Moreover the shape
of the compliance boundary shall be accurately described in the assessment report. Clause 7
gives information on field measurements.
Basic restriction evaluation and field evaluation according to the reference levels can give
directly the compliance distances.
In the case of field measurements, the compliance boundary may be deduced by scaling the
results with measurement distance, relevant input powers, relevant frequencies, bands and
modes, provided the resulting compliance boundary is entirely outside the antenna reactive
near field. Clause 8 gives information on field levels calculations.
5.3 Representative antennas for each service
For each band, the representative antennas are defined in Table 2 for defined broadcasting
bands. In this example they are bands defined by the European Conference of Postal and
Telecommunications Administrations (CEPT).

– 12 – 62577 © IEC:2009
Table 2 – Representative antennas
Representative antennas (in free
Frequency bands and services
space conditions)
VHF Band I (47 MHz – 68 MHz) mainly TV broadcast services λ/2 dipole tuned at 57 MHz
VHF Band II (88 MHz – 108 MHz) mainly sound FM broadcast services λ/2 dipole tuned at 98 MHz
VHF Band III (174 MHz – 230 MHz) λ/2 dipole tuned at 202 MHz
UHF Band IV (470 MHz – 650 MHz) mainly TV broadcast services
λ/2 dipole tuned at 560 MHz
UHF Band V (650 MHz – 862 MHz) mainly TV broadcast services
λ/2 dipole tuned at 706 MHz
SHF band L (1 452 MHz – 1 467,5 MHz) Horn antenna centred at 1 460 MHz,
with gain of 6 dBi
All other broadcasting bands above 2 GHz up to 40 GHz Horn antenna centred at the middle of
the band with a gain of 20 dBi
With this list of representative antennas, it is possible to qualify all broadcast transmitters with
three characteristics, power, frequency and modulation, and to fix a compliance boundary.
Compliance boundary examples for representative antennas are detailed in Annex B.
6 SAR measurement and calculation
6.1 Whole-body SAR inherent compliance
If the maximum r.m.s. power of a transmitter is less than the values specified in the next
equation (10), the maximum exposure will not exceed the whole-body averaged SAR
compliance limits under any conditions and thus whole-body SAR measurements are not
necessary.
P [W] = SAR [W/kg] × 12,5 [kg] (10)

max WB
where
P is the maximum r.m.s. power, and
max
SAR is the whole-body SAR limit.
WB
The whole-body SAR exclusion power levels have been derived based on the following
assumptions:
a) all of the power emitted from the transmitter through the antenna is absorbed in the body
(worst-case assumption);
rd
b) the body mass for a 4-year-old child has been taken as 12,5 kg. This is the 3 percentile
body weight data for girls and women.
6.2 SAR compliance
Whole-body and localised SAR measurements and calculations are described in EN 50413.
7 Electromagnetic field measurement
7.1 Measurement
The methods used are to measure directly or indirectly the E-field or H-field strength and
deduce the field distribution for a given input power and frequency.

62577 © IEC:2009 – 13 –
Dependent on the application, the field measurements (E and H and therefore the power
density) can be obtained at points of investigation, either along a line or by surface or volume
scanning.
Table 3 describes the recommended resolution bandwidth (RBW) and video bandwidths (VBW)
for different types of radio services to take their modulation into account, but other parameters
can be used provided that they are justified.
Table 3 – Recommended parameters
Type of service RBW VBW
kHz kHz
FM 300 30
TV video 1 000 300
TV audio 300 30
Digital TV (DVB) 8 000 300
a
Digital TV (ISDB-T) 6 000  300
Digital radio (DAB) 2 000 100
b a
Digital radio (ISDB-Tsb)
428,5×N  100
a
Example
b
N is total number of segments
Annex A details one possible measurement method: the volume measurement. Other methods
can be used with appropriate justifications.
7.2 Measurement uncertainty
7.2.1 Expression of uncertainty in measurement
The evaluation of uncertainty in the measurement of the electromagnetic fields values shall be
based on the general rules provided by the ISO/IEC Guide to the expression of uncertainty in
measurement. An evaluation of type A as well as type B of the standard uncertainty shall be
used.
When a type A analysis is performed, the standard uncertainty (u ) shall be derived from the
j
estimate from statistical observations. When type B analysis is performed, u comes from the
j
upper (a ) and lower (a ) limits of the quantity in question, depending on the distribution law
+ -
defining
a = (a - a )/2
+ -
then:
a
– rectangular law: u =
i
a
– triangular law: u =
i
a
– normal law: u = where k is a coverage factor
i
k
a
– U-shaped (asymmetric): u =
i
– 14 – 62577 © IEC:2009
7.2.2 Contribution of the measurement equipment
a) Calibration of the measurement equipment
The uncertainty in the sensitivity shall be evaluated assuming a normal probability
distribution.
b) Probe isotropy
The uncertainty due to isotropy shall be evaluated with a rectangular probability
distribution.
c) Probe linearity
A correction shall be performed to establish linearity. The uncertainty is considered after
this correction. The uncertainty due to linearity shall be evaluated assuming it has a
rectangular probability distribution.
d) E-field or H-field values out of measurement range
Errors may be introduced if local measurements are outside the measurement range of
the measurement device. If an E-field or H-field level is below the lower detection limit,
then the value of the measurement device detection limit shall be used. If the E-field or H-
field level is above the upper measurement device limit then the measurement shall be
considered invalid. The uncertainty due to detection limits shall be evaluated assuming it
has a rectangular probability distribution.
e) Measurement device
The uncertainty contribution from the measurement device shall be evaluated with
reference to its calibration certificates. The uncertainty due to the measurement device
shall be evaluated assuming a normal probability distribution.
f) Electrical noise
This is the signal detected by the measurement system even if the EUT is not transmitting.
The sources of these signals include RF noise (lighting systems, the scanning system,
grounding of the laboratory power supply, etc.), electrostatic effects (movement of the
probe, people walking, etc.) and other effects (light-detecting effects, temperature, etc.).
The electrical noise level shall be determined by three different coarse scans with the RF
source switched off or with an absorbing load connected to the output of the transmitter.
None of the evaluated points shall exceed - 25 dB of the lowest incident field being
measured. Within this constraint, the uncertainty due to noise shall be neglected.
g) Contribution of the power chain
The mismatch in the power chain leads to an uncertainty in the evaluation of the emitted
power from the power measured by the power metre.
h) Contribution of the mechanical constraint
The mechanical constraints of the positioning system introduce uncertainty to the
electromagnetic fields measurements through the accuracy and repeatability of positioning.
These parameters shall be evaluated with reference to the positioning system’s
specifications. The uncertainty in distance between the measurement point and the EUT
shall be added directly to the compliance distance and shall play no other part in
uncertainty calculations.
62577 © IEC:2009 – 15 –
i) Matching between probe and EUT references
Before each scan the alignment between position of the probe and the EUT shall be
verified using three reference points.
7.2.3 Contribution of physical parameters
a) Drift in input power of the EUT, probe, temperature and humidity
The drift due to electronics of the EUT and the measurement equipment, as well as
temperature and humidity, are controlled by the first and last step of the measurement
process defined in the measurement procedure and the resulting error shall be less than
± 5 %. The uncertainty shall be evaluated assuming a rectangular probability distribution.
b) Perturbation by the environment
The perturbation of the environment results from various contributing factors:
• reflection of wave in the laboratory;
• influence of the EUT and isotropic probe positioner;
• influence of cables and equipment;
• background level of electromagnetic fields.
7.2.4 Contribution of the post-processing
The error introduced by the extrapolation and interpolation algorithms shall be evaluated
assuming a normal probability distribution.
7.2.5 Uncertainty evaluation
7.2.5.1 Combined and expanded uncertainties
The contributions of each component of uncertainty shall be registered with their name,
probability distribution, sensitivity coefficient and uncertainty value. The results shall be
recorded in a table of the following form. The combined uncertainty shall then be evaluated
according to the following formula:
m
2 2
u = c ⋅ u (11)
c
∑
i i
i =1
where
c is the weighting coefficient (sensitivity coefficient).
i
The expanded uncertainty shall be evaluated using a confidence interval of 95 %.

– 16 – 62577 © IEC:2009
Table 4 – Uncertainty evaluation
Uncertainty sources Description Uncertainty Probability Divisor c Standard
i
(subclause) value for E distribution uncertainty
and H
% %
Measurement equipment
7.2.2
Calibration  Normal 1 or k 1
Isotropy  Rectangular 1
Linearity  Rectangular 1
Fields out of measurement range  Rectangular 1
Measurement device  Normal 1 or k 1
Noise  Normal 1 1
Power chain  Normal 1 1
Mechanical constraints 0
Positioning system  Rectangular 1
Matching between probe and the EUT  Rectangular 1
Physical parameters 7.2.3
Drifts in output power of the EUT, probe,
Rectangular 1
temperature and humidity
Perturbation by the environment  Rectangular 1
m
2 2
Combined standard uncertainty (11) u = c ⋅u

c ∑ i i
i =1
Expanded uncertainty
u = 1,96 u
Normal
e c
(confidence interval of 95 %)
7.2.5.2 Maximum expanded uncertainty
After scaling post-processing, as illustrated in A.3.2, the expanded uncertainty shall not
exceed 30 % of the E-field or H-field, a value that has to be considered as the U value of
CISPR 16-4-2. This uncertainty is typically obtained in a laboratory.
8 Electromagnetic field calculation
8.1 Procedures to calculate the electromagnetic field
This clause describes the procedures to calculate, at points of investigation (PI), the
electromagnetic field components and/or power density, radiated by an antenna (see
Figure 1).
62577 © IEC:2009 – 17 –
Start
Reactive or
radiating
near-field
Determine the
See EN 50413
applicable field region
(8.2)
Far-field
Establish far-field
gain G
(θ, Φ)
Determine E or H
or S
Return field value at point
of investigation
IEC  1498/09
Figure 1 – Alternative routes to calculate E-field, H-field values
at point of investigation
8.2 Field regions
8.2.1 General
Calculations can be made in three separate regions, based on distance from the antenna.
These are called
– far-field region,
– radiating near-field region,
– reactive near-field region.
The theory that defines these regions is given in the generic and basic standard.
8.2.2 Far-field region
The far-field calculations are accurate when the distance r from an antenna of maximum
dimension D, to a point of investigation is greater than:
2D
r =
λ
and
r >> D and r >> λ.
– 18 – 62577 © IEC:2009
8.2.3 Radiating near-field region
The radiating near-field region of an antenna of length D, this region is defined by
λ 2D
< r ≤
4 λ
where
r is the distance from the antenna to the point of investigation.
8.2.4 Reactive near-field region
The reactive near-field region of an antenna, this region is defined by
λ
r ≤
where
r is the distance from the antenna to the point of investigation.
8.3 Calculation models
8.3.1 General
Free space analysis shall be considered in calculation if the influence of the environment is
shown as negligible.
More information is given in EN 50413.
8.3.2 Far-field
8.3.2.1 Analytical Model
This model is applicable in the far-field region and over-estimates in the radiating near-field
region.
PG()θ,φ
i
The power density: S = (12)
4πr
30PGi
(θ,φ)
The electric field strength: E = (13)
r
E
The magnetic field strength: H =        (14)
η
where
P is the input power of the antenna;
)
G is the antenna gain relative to an isotropic antenna;
i
θ,φ are the elevation and azimuth angles (Figure A.2);
r is the distance from the antenna to the point of investigation;
___________
The antenna gain G(θ,φ) may be determined according to J. E. Hansen “Spherical near-field antennas
measurements J.” Ed: London P., 1988.

62577 © IEC:2009 – 19 –
η is the free space wave impedance = 120 π Ω.
8.3.2.2 Other models
These models are available in the basic and generic standards.
Then the lower calculated result of cylinder/far-field models may be applied conservatively.
9 Contact currents measurement and calculation
Contact currents arise from a person touching a metallic object in the electromagnetic field
and could create a risk of shock, or burn from light contact of the fingers with the external
object.
It is impossible in a general case to calculate contact currents due the impossibility of defining
a generic coupling structure. In a specific case, at a given situation, calculation could be done
but it is not relevant in this basic standard.
The situation is similar for contact current measurement.
10 Induced current measurement and calculation
Evaluation of induced limbs currents is needed in the frequency range from 30 MHz to
110 MHz. The limb current reference levels are set to prevent excessive localized SAR
induced in any limb. For compliance with the basic restriction on localised SAR, the square
root of the time-averaged value of the square of the induced current over any 6-minute period
forms the basis of the reference levels.
Evaluation by calculation or measurements needs to be performed to evaluate compliance
distance.
Induced current calculation needs quite the same tools and methods as SAR calculation. But
generally approved approach is not yet available in the frequency range from 30 MHz to
110 MHz (especially phantom).
Induced current measurement and calculation are described in EN 50413.

– 20 – 62577 © IEC:2009
Annex A
(normative)
Field measurement in a volume surrounding the EUT
A.1 General
Direct measurements of electric and magnetic fields are made at sufficient points of
investigation in a volume surrounding the EUT to establish the compliance boundary. This
method is only applicable in the far-field. In the near-field, additional post processing is
needed to have a high degree of accuracy
A.2 Measurement equipment and test environment
A.2.1 General description
The volume-scanning equipment consists of a probe and a structure to hold the EUT and the
probe, allowing a 3D movement between the two, all located in a suitable test site.
The following equipment may be required:
– anechoic chamber or outdoor test site;
– electric and/or magnetic probe;
– supporting structure for probe;
– supporting structure for the EUT;
– synthesiser and amplifier(s);
– probe positioning system;
– EUT positioning system;
– receiver or other measurement device.
A computer may be used to control the measurement equipment. The test equipment shall be
placed so as not to influence the measurements. A typical EUT measurement system
configuration is shown in Figure A.1.

EUT
Z
Z
Probe
Y
Y
X
(0, 0, 0)
X
R
ϕ
Positioner
Probe positioning Measurement
Amplifier
Trans-
control
system device
mitter
or
Synthesizer
Data acquisition
and PC control
IEC  1499/09
Figure A.1 – Block diagram of the EUT measurement system
NOTE Measurements on the test site are possible for panels and small antenna systems. For the typical
broadcast antenna systems o
...