BSI PD IEC/TR 62630:2010
$189.07
Guidance for evaluating exposure from multiple electromagnetic sources
Published By | Publication Date | Number of Pages |
BSI | 2010 | 50 |
This Technical Report describes exposure evaluation concepts and techniques for the overall exposure level in spatial regions and occupants caused by the simultaneous exposure to multiple narrowband electromagnetic (EM) sources. Throughout this Technical Report, it is assumed that the exposure evaluation occurs under static conditions, i.e., the source position and transmit-mode characteristics (e.g. emitted power, modulation scheme, etc.) of the device(s) under test do not vary significantly over the time required to carry out the evaluation using the chosen evaluation technique (e.g., field measurements).
The vast majority of wireless communication systems worldwide employ signalling schemes featuring narrowband waveforms, hereinafter defined as signal waveforms occupying a frequency band not broader than 10 % of its central frequency (justification of this threshold is provided below). For information, Annex A presents the operating system bands and channel bandwidths of several common wireless services.
Wide-band communication systems, e.g., ultra-wideband (UWB) systems employing impulsive waveforms with fractional bandwidth well in excess of 10 %, are relatively new to the marketplace, have experienced limited deployment so far, and are not typically regarded as significant contributors to EM exposure levels due to low transmit power levels.
NOTE Present exposure evaluation standards for fixed or mobile wireless communication devices, e.g., IEC 62209-1, are mostly tailored towards defining suitable techniques for narrowband waveforms. For instance, they recommend the use of scalar E-field or H-field sensors, e.g., miniature diode-detector probes, which typically provide accurate readings for narrowband waveforms, as defined herein. The paucity of UWB wireless communication systems, which have only very recently been introduced in the marketplace, as well as the low power levels associated with the corresponding signals to avoid interfering with coexisting electronic systems, has so far reduced the priority to standardize suitable evaluation techniques and to develop the relevant test instrumentation.
PDF Catalog
PDF Pages | PDF Title |
---|---|
4 | CONTENTS |
6 | FOREWORD |
8 | INTRODUCTION |
9 | 1 Scope 2 Normative references |
10 | 3 Terms, definitions and abbreviations 3.1 Terms and definitions |
18 | 3.2 Physical quantities 3.3 Constants 3.4 Abbreviations |
19 | 3.5 Vector notations 4 Overview |
20 | Figures Figure 1 – Electrical paths from the radiating elements of each panel in a dual-panel antenna system to a field-point P on the ρ-z symmetry plane |
21 | Figure 2 – True vector sum of the complex field envelopes produced at the field-point P by the individual antenna panels in Figure 1 at two different measurement times |
22 | 5 Classification of devices and EM sources 5.1 General aspects 5.2 Device classification based on the intended use: user-centric versus node-centric |
23 | 5.3 EM source classification: single-channel versus band-wide transmitters Figure 3 – Simultaneous exposure at the location X by multiple sector-antennas belonging to adjacent tri-sector cellular masts (labelled #1 and #2) |
24 | Tables Table 1 – Source classes: characteristics and examples of source classification |
25 | 6 Combined exposure from multiple narrowband EM sources 6.1 Guidance on the selection of the exposure summation approach Table 2 – Guidance on the selection of suitable evaluation techniques |
26 | 6.2 Correlation between signals emitted by different EM sources 6.3 Relevant exposure metrics |
27 | 6.4 Combined exposure from uncorrelated EM sources 6.5 Combined exposure evaluation of correlated EM sources |
30 | Figure 4 – Different approaches yielding distinct upper-bounds of the field vector-sum |
31 | Annex A (informative) Frequency allocations for some common wireless services Table A.1 – Frequency allocations and bandwidths for common wireless technologies |
34 | Annex B (informative) Supporting analytical details |
39 | Figure B.1 – Vectorial interpretation of inequality (B25), yielding an upper-bound of the true field vector-sum (red arrow) |
41 | Annex C (informative) Examples of combined exposure evaluations Figure C.1 – CAD model of the antenna system for a mobile phone, including a GSM/UMTS antenna and a Bluetooth antenna |
42 | Figure C.2 – Qualitative description of the individual and combined SAR distributions for a mobile phone transmitting simultaneously GSM and Wi-Fi signals |
43 | Figure C.3 – Communications tower shared by different network operators |
44 | Figure C.4 – Smart antenna formed by 8 vertical 5-element ground-backed dipole arrays |
46 | Figure C.5 – Power density distributions on the surface Σρ (ρ = 1 m) derived via Equations (6), (10), and (12) for the 3,5 GHz smart antenna shown in Figure C.4 |
47 | Figure C.6 – Overestimations produced by Equations (10) and (12) over the exposure evaluation area Σρ (ρ = 1 m) for the 3,5 GHz smart antenna shown in Figure C.4 |
48 | Bibliography |