IEC 62232:2011

IEC 62232
®

Edition 1.0 2011-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside


Determination of RF field strength and SAR in the vicinity of
radiocommunication base stations for the purpose of evaluating human
exposure

Détermination des champs de radiofréquences et du DAS aux environs des
stations de base utilisées pour les communications radio dans le but d’évaluer
l’exposition humaine

IEC 62232:2011

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IEC 62232
®
Edition 1.0 2011-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside


Determination of RF field strength and SAR in the vicinity of
radiocommunication base stations for the purpose of evaluating human
exposure

Détermination des champs de radiofréquences et du DAS aux environs des
stations de base utilisées pour les communications radio dans le but d’évaluer
l’exposition humaine

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XH
CODE PRIX
ICS 13.280; 17.240 ISBN 978-2-88912-493-0
® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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– 2 – 62232  IEC:2011
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 11
3 Terms and definitions . 11
4 Symbols and abbreviated terms . 17
4.1 Physical quantities . 17
4.2 Constants . 17
4.3 Abbreviations . 17
5 Developing the evaluation plan . 18
5.1 Overview . 18
5.2 Key tasks . 19
6 Evaluation methods . 21
6.1 Overview . 21
6.2 Measurement methods . 22
6.2.1 Overview of measurement methods . 22
6.2.2 RF field strength measurement . 23
6.2.3 SAR measurement method . 32
6.3 Computation methods. 36
6.3.1 Overview and general requirements . 36
6.3.2 Basic computation methods . 38
6.3.3 Advanced computation methods . 43
6.4 Extrapolation from the evaluated SAR / RF field strength to the required
assessment condition . 52
6.4.1 Extrapolation method . 52
6.4.2 Extrapolation to maximum RF field strength using broadband
measurements . 53
6.4.3 Extrapolation to maximum RF field strength for frequency and code
selective measurements . 53
6.5 Summation of multiple RF fields . 54
6.5.1 Applicability . 54
6.5.2 Uncorrelated fields . 54
6.5.3 Correlated fields . 55
6.5.4 Ambient fields . 55
7 Uncertainty . 55
7.1 Background . 55
7.2 Requirement to estimate uncertainty . 55
7.3 How to estimate uncertainty . 56
7.4 Uncertainty bounds on measurement equipment influence quantities . 56
7.5 Applying uncertainty for compliance assessments . 56
8 Reporting . 57
8.1 Background . 57
8.2 Evaluation report . 57
8.2.1 General . 57
8.2.2 Measurement data sheet . 57
8.2.3 Computational data sheet . 58
8.2.4 Final report . 58

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62232  IEC:2011 – 3 –
8.3 Interpretation of results . 59
8.3.1 Comparison with limit . 59
8.3.2 Comparing results . 59
8.3.3 Opinions and interpretations . 59
Annex A (normative) Developing the evaluation plan . 60
Annex B (normative) Defining the source-environment plane . 69
Annex C (informative) Guidance on the application of the standard to specific
evaluation purposes . 78
Annex D (normative) Evaluation parameters . 84
Annex E (normative) RF field strength measurement equipment requirements . 88
Annex F (informative) Basic computation implementation. 89
Annex G (normative) Advanced computation implementation . 97
Annex H (normative) Validation of computation methods. 101
Annex I (informative) Guidance on spatial averaging schemes . 110
Annex J (informative) Guidance on addressing time variation of signals in
measurement . 112
Annex K (informative) Guidance on determining ambient field levels . 113
Annex L (informative) Guidance on comparing evaluated parameters with a limit value . 117
Annex M (informative) Guidance on assessment schemes . 119
Annex N (informative) Guidance on specific technologies . 127
Annex O (informative) Guidance on uncertainty . 151
Annex P (informative) Case studies . 165
Bibliography . 175

Figure 1 – Overview of evaluation methods . 21
Figure 2 – Overview of RF field strength measurement methods . 22
Figure 3 – Positioning of the EUT relative to the relevant phantom . 33
Figure 4 – Overview of computation methods . 37
Figure 5 – Reflection due to the presence of a ground plane . 39
Figure 6 – Enclosed cylinder around collinear arrays, with and without electrical
downtilt . 40
Figure 7 – Directions for which SAR estimation expressions are given . 41
Figure 8 – Ray tracing (synthetic model) geometry and parameters . 44
Figure B.1 – Source-environment plane concept . 69
Figure B.2 – Geometry of an antenna with largest linear dimension L and largest
eff
end dimension L . 70
end
Figure B.3 – Maximum path difference for an antenna with largest linear dimension L . 75
Figure B.4 – Example source-environment plane regions near a roof-top antenna which
has a narrow vertical (elevation plane) beamwidth (not to scale) . 77
Figure C.1 – Example of complex compliance boundary . 79
Figure C.2 – Example of circular cylindrical compliance boundaries: (a) sector
coverage antenna, (b) horizontally omnidirectional antenna . 79
Figure C.3 – Example of parallelepipedic compliance boundary . 80
Figure C.4 – Example illustrating the linear scaling procedure . 80
Figure C.5 – Example investigation process . 83

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– 4 – 62232  IEC:2011
Figure D.1 – Cylindrical, cartesian and spherical coordinates relative to the RBS
antenna . 84
Figure F.1 – Reference frame employed for cylindrical formulae for field strength
computation at a point P (left), and on a line perpendicular to boresight (right) . 89
Figure F.2 – Two (a) and three (b) dimensional views illustrating the three valid zones
for field strength computation around an antenna. 90
Figure F.3 – Leaky feeder geometry . 95
Figure H.1 – Cylindrical formulae reference results . 101
Figure H.2 – Spherical formulae reference results . 102
Figure H.3 – Line 4 far-field positions for ray tracing validation example . 103
Figure H.4 – Antenna parameters for ray tracing algorithm validation example . 104
Figure H.5 – Generic 900 MHz RBS antenna with nine dipole radiators . 106
Figure H.6 – Line 1, 2 and 3 near-field positions for full wave and ray tracing validation . 106
Figure H.7 – Generic 1 800 MHz RBS antenna with five slot radiators . 108
Figure H.8 – RBS antenna placed in front of a multi-layered lossy cylinder . 109
Figure I.1 – Spatial averaging schemes relative to foot support level . 111
Figure I.2 – Spatial averaging relative to spatial-peak field strength point height . 111
Figure K.1 – Evaluation locations . 115
Figure K.2 – Relationship of separation of remote radio source and evaluation area to
separation of evaluation points . 116
Figure M.1 – Target uncertainty scheme overview . 121
Figure M.2 – Evaluation of compliance with limit . 122
Figure M.3 – Evaluation with confidence that limit is exceeded . 123
Figure N.1 – Spectral occupancy for GMSK . 133
Figure N.2 – Spectral occupancy for CDMA . 134
Figure N.3 – Channel allocation for a WCDMA signal . 137
Figure N.4 – Example of Wi-Fi frames . 140
Figure N.5 – Channel occupation versus the integration time for 802.11b standard . 140
Figure N.6 – Channel occupation versus nominal throughput rate for 802.11b/g
standards . 141
Figure N.7 – Wi-Fi spectrum trace snapshot . 141
Figure N.8 – Plan view representation of statistical conservative model . 143
Figure N.9 – Binomial cumulative probability function for N = 24, PR = 0,125 . 149
Figure N.10 – Binomial cumulative probability function for N = 18, PR = 2/7 . 150
Figure O.1 – Probability of the true value being above (respectively below) the
evaluated value depending on the confidence level assuming a normal distribution . 154
Figure O.2 – Plot of the calibration factors for E (not E²) provided from an example
calibration report for an electric field probe . 156
Figure O.3 – Computational model used for the variational analysis of reflected RF

fields from the front of a surveyor . 161
Figure P.1 – Micro cell case study . 166
Figure P.2 – Roof-top case study (a) with nearby apartment buildings (b) . 167
Figure P.3 – Roof-top/tower case study (a) in residential area (b) . 168
Figure P.4 – Roof-top case study with direct access to antennas . 169
Figure P.5 – Roof-top case study with large antennas and no direct access . 170

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62232  IEC:2011 – 5 –
Figure P.6 – Cylindrical compliance boundary determination for dual band antenna on
building . 171
Figure P.7 – Tower case study (a) in parkland (b) . 172
Figure P.8 – Multiple towers case study (a) at sports venue (b) . 173
Figure P.9 – Office building in building coverage case study . 174

Table 1 – Checklist for the evaluation plan . 20
Table 2 – Sample template for estimating the expanded uncertainty of a RF field
strength measurement that used a frequency-selective instrument. 30
Table 3 – Sample template for estimating the expanded uncertainty of a RF field
strength measurement that used a broadband instrument . 31
Table 4 – Applicability of computation methods for source-environment regions of
Figure B.1 . 38
Table 5 – Applicability of SAR estimation formulae . 42
Table 6 – Sample template for estimating the expanded uncertainty of a ray tracing RF
field strength computation . 46
Table 7 – Sample template for estimating the expanded uncertainty of a full wave RF
field strength computation . 49
Table 8 – Sample template for estimating the expanded uncertainty of a full wave SAR
computation . 51
Table A.1 – Measurand validity for evaluation points in each source region . 62
Table A.2 – Guidance on selecting between computation and measurement
approaches . 63
Table A.3 – Selecting in situ or laboratory measurement from evaluation purpose and
RBS category . 64
Table A.4 – Guidance on selecting between broadband and frequency-selective
measurement . 65
Table A.5 – Guidance on selecting RF field strength measurement procedures . 66
Table A.6 – Guidance on selecting computation methods . 67
Table A.7 – Guidance on specific evaluation method ranking . 68
Table B.1 – Definition of source regions . 71
Table B.2 – Default source region boundaries . 71
Table B.3 – Source region boundaries for antennas with maximum dimension less
than 2,5 λ . 72
Table B.4 – Source region boundaries for linear/planar antenna arrays with a maximum
dimension greater than or equal to 2,5 λ . 72
Table B.5 – Source region boundaries for equiphase radiation aperture (e.g. dish)
antennas with maximum reflector dimension much greater than a wavelength . 73
Table B.6 – Source region boundaries for leaky feeders . 73
Table B.7 – Far-field distance r measured in metres as a function of angle β . 75
Table D.1 – Dimension variables . 85
Table D.2 – RF power variables . 85
Table D.3 – Antenna variables . 86
Table D.4 – Measurand variables . 87
Table E.1 – Broadband measurement system requirements . 88
Table E.2 – Frequency-selective measurement system requirements . 88
Table F.1 – Definition of boundaries for selecting the zone of computation . 91

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– 6 – 62232  IEC:2011
Table F.2 – Definition of . 93
C( f )
Table H.1 – Input parameters for cylinder and spherical formulae validation . 101
Table H.2 – Input parameters for SAR estimation formulae validation . 102
Table H.3 – SAR and SAR estimation formulae reference results for Table H.2
10g wb
parameters . 102
Table H.4 – Ray tracing power density reference results . 105
Table H.5 – Validation 1 full wave field reference results . 107
Table H.6 – Validation 2 full wave field reference results . 108
Table H.7 – Validation reference SAR results for computation method . 109
Table M.1 – Examples of general assessment schemes . 120
Table M.2 – Determining target uncertainty . 122
Table M.3 – Monte Carlo simulation of 10 000 trials both surveyor and auditor using
best estimate . 125
Table M.4 – Monte Carlo simulation of 10 000 trials both surveyor and auditor using
target uncertainty of 4 dB . 125
Table M.5 – Monte Carlo simulation of 10 000 trials surveyor uses upper 95 % CI vs.
auditor uses lower 95 % CI . 126
Table N.1 – Technology specific information . 128
Table N.2 – Example of spectrum analyser settings for an integration per service. 135
Table N.3 – Example constant power components for specific technologies . 136
Table N.4 – CDMA decoder requirements . 137
Table N.5 – Signals configuration . 138
Table N.6 – CDMA generator setting for power linearity . 138
Table N.7 – WCDMA generator setting for decoder calibration . 139
Table N.8 – CDMA generator setting for reflection coefficient measurement . 139
Table O.1 – Guidance on minimum separation distances for some dipole lengths to
ensure that the uncertainty does not exceed 5 % or 10 % in a measurement of E. . 159
Table O.2 – Guidance on minimum separation distances for some loop diameters to
ensure that the uncertainty does not exceed 5 % or 10 % in a measurement of H. . 160
Table O.3 – Example minimum separation conditions for selected dipole lengths for
10 % uncertainty in E . 160
Table O.4 – Standard estimates of dB variation for the perturbations in front of a
surveyor due
...