IEC/IEEE 62704-4:2020

IEC/IEEE 62704-4 ®
Edition 1.0 2020-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Determining the peak spatial-average specific absorption rate (SAR) in the
human body from wireless communication devices, 30 MHz to 6 GHz –
Part 4: General requirements for using the finite element method for SAR
calculations
Détermination du débit d’absorption spécifique (DAS) maximal moyenné
dans le corps humain, produit par les dispositifs de communications sans fil,
30 MHz à 6 GHz –
Partie 4: Exigences générales d'utilisation de la méthode des éléments finis
pour les calculs du DAS
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IEC/IEEE 62704-4 ®
Edition 1.0 2020-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Determining the peak spatial-average specific absorption rate (SAR) in the

human body from wireless communication devices, 30 MHz to 6 GHz –

Part 4: General requirements for using the finite element method for SAR

calculations
Détermination du débit d’absorption spécifique (DAS) maximal moyenné

dans le corps humain, produit par les dispositifs de communications sans fil,

30 MHz à 6 GHz –
Partie 4: Exigences générales d'utilisation de la méthode des éléments finis

pour les calculs du DAS
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.220.20 ISBN 978-2-8322-8535-0

– 2 – IEC/IEEE 62704-4:2020 © IEC/IEEE 2020
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 8
4 Abbreviated terms . 9
5 Finite element method – basic description . 9
6 SAR calculation and averaging . 10
6.1 General . 10
6.2 SAR averaging . 11
6.2.1 General . 11
6.2.2 Evaluation of psSAR with an FEM mesh . 11
6.3 Power scaling . 12
7 Considerations for the uncertainty evaluation . 12
7.1 General . 12
7.2 Uncertainty due to device positioning, mesh density, and simulation
parameters . 13
7.2.1 General . 13
7.2.2 Mesh convergence. 14
7.2.3 Open boundary conditions . 14
7.2.4 Power budget . 14
7.2.5 Convergence of psSAR sampling . 14
7.2.6 Dielectric parameters of the phantom or body model . 15
7.3 Uncertainty and validation of the developed numerical model of the DUT . 15
7.3.1 General . 15
7.3.2 Uncertainty of the DUT model (d ≥ λ/2 or d ≥ 200 mm) . 16
7.3.3 Uncertainty of the DUT model (d < λ/2 and d < 200 mm) . 17
7.3.4 Phantom uncertainty (d < λ/2 and d < 200 mm) . 18
7.3.5 Model validation . 19
7.4 Uncertainty budget . 19
8 Code verification. 20
8.1 General . 20
8.1.1 Rationale . 20
8.1.2 Code performance verification . 21
8.1.3 Canonical benchmarks . 21
8.2 Code performance verification . 21
8.2.1 Propagation in a rectangular waveguide . 21
8.2.2 Planar dielectric boundaries . 26
8.2.3 Open boundary conditions . 28
8.3 Weak patch test . 28
8.3.1 General . 28
8.3.2 Free-space weak patch test . 29
8.3.3 Dielectric-layer weak patch test . 33
8.4 Verification of the psSAR calculation . 36
8.5 Canonical benchmarks . 36
8.5.1 Mie sphere . 36

8.5.2 Generic dipole . 37
8.5.3 Microstrip terminated with open boundary conditions . 38
8.5.4 psSAR calculation SAM phantom / generic phone . 39
8.5.5 Setup for system performance check . 39
Annex A (informative) Fundamentals of the finite element method . 41
A.1 General . 41
A.2 Model boundary value problem . 41
A.3 Galerkin weak form . 42
A.4 Finite element approximation . 42
A.5 Considerations for using FEM . 43
Annex B (informative) File format for field and SAR data. 44
Annex C (informative) Analytical solution for error calculation in weak patch-test
problems . 45
C.1 Generation of control mesh and FEM field values . 45
C.2 Free-space weak patch test . 45
C.3 Dielectric-layer weak patch test . 45
Bibliography . 48

Figure 1 – Waveguide filled half with free-space (green) and half with dielectric (blue) . 24
Figure 2 – Aligned rectangular waveguide and locations of the sample points E , E ,
01 10
E , E and E at which the E components are recorded . 25
11 12 21 x
Figure 3 – Weak patch test arrangement: a free-space cube with edge length L
illuminated by a plane wave . 29
Figure 4 – Dielectric-layer weak patch test arrangement . 33
Figure 5 – Geometry of the microstrip line . 38
Figure 6 – Geometry of the setup for the system performance check according to [21] . 40

Table 1 – Budget of the uncertainty contributions of the numerical algorithm and of the
rendering of the test-setup or simulation-setup . 13
Table 2 – Budget of the uncertainty of the developed model
...