IEC TR 63377:2022

Procedures for the assessment of human exposure to electromagnetic fields from radiative wireless power transfer systems – Measurement and computational methods (frequency range of 30 MHz to 300 GHz)

IEC TR 63377:2022 describes assessment methods to evaluate the compliance of radiative wireless power transfer (WPT) systems operating in the frequency range from 30 MHz to 300 GHz with electromagnetic guidelines on human exposure (electromagnetic field strength, specific absorption rate (SAR), and power density). This document includes but is not limited to systems that focus the electromagnetic energy emitted by the transmitter to regions surrounding the receiver, for example, by narrow beam-forming systems, wide-beam systems and spatially closed systems. Implementations without transmitter, for example, applications that harvest energy from the environment, are not included in the scope of this document.

General Information

• Status: Published
• Publication Date: 03-Nov-2022
• ICS: 17.220.20 - Measurement of electrical and magnetic quantities
• ICS: 33.050.10 - Telephone equipment
• Technical Committee: TC 106 - Methods for the assessment of electric, magnetic and electromagnetic fields associated with human exposure
• Drafting Committee: WG 9 - TC 106/WG 9
• Current Stage: PPUB - Publication issued
• Start Date: 24-Nov-2022
• Completion Date: 04-Nov-2022

Standards Content (Sample)

IEC TR 63377 ®
Edition 1.0 2022-11
TECHNICAL
REPORT
colour
inside
Procedures for the assessment of human exposure to electromagnetic fields
from radiative wireless power transfer systems – Measurement and
computational methods (frequency range of 30 MHz to 300 GHz)
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IEC TR 63377 ®
Edition 1.0 2022-11
TECHNICAL
REPORT
colour
inside
Procedures for the assessment of human exposure to electromagnetic fields

from radiative wireless power transfer systems – Measurement and

computational methods (frequency range of 30 MHz to 300 GHz)

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 17.220.20, 33.050.10 ISBN 978-2-8322-5945-0

– 2 – IEC TR 63377:2022 © IEC 2022
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 8
4 Symbols and abbreviated terms . 10
4.1 Physical quantities . 10
4.2 Constants . 11
4.3 Abbreviated terms . 11
5 Description of radiative wireless power transfer systems . 12
5.1 General . 12
5.2 Radiative WPT systems technology and applications . 12
5.2.1 General . 12
5.2.2 Operating principle of space diversity WPT . 15
5.2.3 Operating principle of narrow-beam WPT. 16
5.3 Use cases and environment . 16
5.3.1 General . 16
5.3.2 Indoor, occupational environment . 16
5.3.3 Indoor, general-public environment . 18
5.3.4 Outdoor, occupational environment. 18
5.3.5 Outdoor, general-public environment . 19
6 General exposure assessment considerations . 19
6.1 General . 19
6.2 Preparation of assessment . 19
6.2.1 General . 19
6.2.2 Determination of key parameters . 19
6.2.3 Determination of applicable limits . 20
6.2.4 Determination of assessment method . 21
6.3 Assessment conditions . 23
6.4 Uncertainty . 23
Annex A (informative) Coupling factors and correction factors . 26
A.1 General . 26
A.2 Coupling factors for near-field exposure . 27
A.2.1 Characteristics of the near-field . 27
A.2.2 Coupling of electromagnetic energy in the near-field . 27
A.2.3 Considerations for whole-body exposure in the near-field . 27
A.2.4 Derivation of the coupling factors for E-field or H-field exposure . 27
A.3 Correction factors for far-field exposures . 28
A.3.1 Characteristics of the far-field . 28
A.3.2 Tissue layering . 28
A.3.3 Whole-body absorption and resonance . 29
A.3.4 Conservative correction factors . 29
A.4 Assessment of correction factors for layered tissues . 30
A.4.1 General . 30
A.4.2 Correction factors for peak-spatial average SAR . 30
A.4.3 Correction factors for whole-body SAR . 30

A.4.4 Correction factors for partial body exposures . 30
A.4.5 Correction of SAR results in homogeneous flat phantoms . 31
Annex B (informative)  Assessment procedure . 32
B.1 RF field strength and power density assessment for radiative WPT systems . 32
B.2 Local SAR assessment for radiative WPT systems operating between
30 MHz to 6 GHz . 32
B.2.1 General . 32
B.2.2 Preparation of the device under test . 33
B.2.3 Transmitter SAR assessment procedure . 33
B.2.4 Validation of the SAR assessment . 34
B.3 Incident power density (PD) assessment for local exposure over 6 GHz. 34
B.3.1 General . 34
B.3.2 Preparation of the device under test . 35
B.3.3 PD assessment procedure – Experimental only . 35
B.3.4 PD assessment procedure – Combined numerical and experimental

methods . 35
B.3.5 Validation of the assessment . 36
Annex C (informative) Description and validation of exposure mitigation techniques . 37
C.1 General . 37
C.2 Description of the technology and its implementation . 37
C.3 Validation of proximity sensors . 37
C.4 Validation of time-period power control . 38
C.5 System level validation of the exposure mitigation techniques . 38
Annex D (informative)  Computational methods. 39
D.1 Methods and procedures . 39
D.2 Verification of the computational method . 39
D.3 Application of hybrid computational and experimental methods . 40
D.4 Considerations for the assessment of the numerical uncertainty . 40
D.4.1 General . 40
D.4.2 Parameters for the numerical uncertainty assessment . 40
Annex E (informative)  Examples of exposure assessment . 41
E.1 Example of the dosimetric assessment of a WPT transmitter operating at
900 MHz . 41
E.1.1 Overview . 41
E.1.2 Method . 41
E.1.3 Model development and validation . 42
E.1.4 Dosimetric assessment of the anatomical models . 42
E.1.5 Results and conclusions . 43
E.2 Example E-field assessment of RF WPT system operating at 2,45 GHz . 43
E.2.1 General . 43
E.2.2 Assessment procedure . 44
E.2.3 E-field assessment results . 45
Bibliography . 50

Figure 1 – WPT system classification via radio-frequency beam technologies . 14
Figure 2 – Beam pattern diagram of omnidirectional radiative WPT. 15
Figure 3 – Beam pattern diagram of space diversity WPT . 15
Figure 4 – Beam pattern diagram of narrow-beam radiative WPT . 16

– 4 – IEC TR 63377:2022 © IEC 2022
Figure 5 – Example of indoor and occupational environments: WPT to production
equipment sensors in factory . 17
Figure 6 – Example of indoor and occupational environments: WPT to machine and

line management sensors . 17
Figure 7 – WPT to children watching sensors . 18
Figure 8 – WPT to watching sensors in nursing homes . 18
Figure 9 – Assessment process for radiative WPT .
...