EN 50361:2001

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Basic standard for the measurement of Specific Absorption Rate related to human exposure to electromagnetic fields from mobile phones (300 MHz - 3 GHz)Grundnorm zur Messung der Spezifischen Absorptionsrate (SAR) in Bezug auf die Sicherheit von Personen in elektromagnetischen Feldern von Mobiltelefonen (300 MHz bis 3 GHz)Norme de base relative à la mesure du Débit d'Absorption Spécifique relatif à l'exposition des personnes aux champs électromagnétiques émis par les téléphones mobiles (300 MHz - 3 GHz)Basic standard for the measurement of Specific Absorption Rate related to human exposure to electromagnetic fields from mobile phones (300 MHz - 3 GHz)33.070.01Mobilni servisi na splošnoMobile services in general13.280Varstvo pred sevanjemRadiation protectionICS:Ta slovenski standard je istoveten z:EN 50361:2001SIST EN 50361:2002en01-januar-2002SIST EN 50361:2002SLOVENSKI
STANDARD
EUROPEAN STANDARDEN 50361NORME EUROPÉENNEEUROPÄISCHE NORMJuly 2001CENELECEuropean Committee for Electrotechnical StandardizationComité Européen de Normalisation ElectrotechniqueEuropäisches Komitee für Elektrotechnische NormungCentral Secretariat: rue de Stassart 35, B - 1050 Brussels© 2001 CENELEC -All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.Ref. No. EN 50361:2001 EICS 33.060.01; 33.100.01English versionBasic standard for the measurement of Specific Absorption Raterelated to human exposure to electromagnetic fields from mobile phones(300 MHz - 3 GHz)Norme de base relative à la mesuredu Débit d'Absorption Spécifique relatifà l'exposition des personnes aux champsélectromagnétiques émis par lestéléphones mobiles (300 MHz - 3 GHz)Grundnorm zur Messung der SpezifischenAbsorptionsrate (SAR) in Bezug aufdie Sicherheit von Personen inelektromagnetischen Feldern vonMobiltelefonen (300 MHz bis 3 GHz)This European Standard was approved by CENELEC on 2001-07-03. CENELEC members are bound tocomply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving thisEuropean Standard the status of a national standard without any alteration.Up-to-date lists and bibliographical references concerning such national standards may be obtained onapplication to the Central Secretariat or to any CENELEC member.This European Standard exists in three official versions (English, French, German). A version in anyother language made by translation under the responsibility of a CENELEC member into its ownlanguage and notified to the Central Secretariat has the same status as the official versions.CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway,Portugal, Spain, Sweden, Switzerland and United Kingdom.SIST EN 50361:2002

- 3 -EN 50361:2001Contents1Scope.42Normative references.43Physical quantities, units and constants.43.1Physical quantities.43.2Constants.54Definitions.55Measurement system specifications.95.1General requirements.95.2Phantom specifications (shell and liquid).105.3Specifications of the SAR measurement equipment.115.4Scanning system specifications.125.5Mobile phone holder specifications.125.6Other equipment.126Protocol for SAR assessment.126.1Measurement preparation.126.2Tests to be performed.156.3Measurement procedure.166.4Post-processing.167Uncertainty assessment.177.1General requirements.177.2Components contributing to uncertainty.177.3Uncertainty assessment.228Measurement report.248.1General.248.2Items to be recorded in the test report.24Annex A (informative) Phantom specifications.25A.1Rationale for the phantom shape.25A.2Tissue Equivalent Liquids.27A.3Preparation of Tissue Equivalent Material.27A.4Measurement of the dielectric properties of liquids and uncertainty estimation.28Annex B (informative) Calibration of the measurement equipment (linearity, isotropy,sensitivity) and uncertainty assessment .32B.1Introduction.35B.2Assessment of the sensitivity of the dipole sensors.32B.3Isotropy.39B.4Linearity.41B.5Lower detection limit.41B.6Boundary effects.42B.7Response time.42Annex C (informative) Post-processing techniques and uncertainty assessment.43C.1Extrapolation and interpolation schemes.43C.2Averaging scheme and maximum finding.44Annex D (normative) Measurement system validation.48D.1Simplified performance checking.48D.2System Validation.50SIST EN 50361:2002

- 5 -EN 50361:2001Permittivityεfarad per metreF/mSpecific absorption rate SARwatt per kilogramW/kgWavelengthλmetremTemperatureTkelvinKHeat capacityciJ/kg KNOTE In this standard, temperature is quantified in degrees Celsius, as defined by:T(°C) = T(K) – 273,163.2 ConstantsPhysical constantMagnitudeSpeed of light in vacuumc2,998 x 108 m/sPermittivity of free spaceε08,854 x 10-12 F/mPermeability of free spaceµ04π x 10-7 H/mImpedance of free spaceZ0120π or 377 Ω4 Definitions4.1.1average (temporal) absorbed power (Pavg)the time-averaged rate of energy transfer defined by: Pavg__=1t2−t1P(t)dtt1t2(4.1)where t1 and t2 are the start and stop time of the exposure. The period t2 - t1 is the exposure durationtime4.1.2averaging time (tavg)the appropriate time over which exposure is averaged for purposes of determining compliance withthe limits4.1.3basic restrictionthe basic restrictions are the restrictions on exposure to time-varying electric, magnetic, andelectromagnetic fields that are based directly on established health effects. Concerning the frequencyrange of this standard, the physical quantity used is the Specific Absorption Rate (SAR)4.1.4boundary effectin this context the boundary effect is the influence of the boundaries between two media of thephantom on the sensitivity of the probe, as well as the influence of the probe on the field distributionand the current density if the probe approaches the boundary between two mediaSIST EN 50361:2002

- 7 -EN 50361:20014.1.14isotropydeviation of the measured value with regard to various angles of incidence of the measured signal. Inthis document it is defined for incidences covering a hemisphere centred at the tip of the probe, withan equatorial plane normal to the probe and expanding outside the probe. The axial isotropy isdefined by the maximum deviation of the SAR when rotating the probe along its main axis with theprobe exposed to a reference wave with normal incidence with regard to the axis of the probe. Thehemispherical isotropy is defined by the maximum deviation of the SAR when rotating the probealong its main axis with the probe exposed to a reference wave with varying angles of incidences withregard to the axis of the probe in the half space in front of the probe4.1.15linearitymaximum deviation over the measurement range of the measured quantity from the closest linearreference curve defined over a given interval4.1.16loss tangentthe loss tangent tan(δ) is the ratio of the imaginary part of the complex dielectric constant of amaterial to its real part4.1.17magnetic flux density (B)the magnitude of a field vector that is equal to the magnetic field strength H multiplied by thepermeability (µ) of the medium.B=µH(4.4)Magnetic flux density is expressed in units of tesla (T)4.1.18magnetic field strength (H)the magnitude of a field vector in a point that results in a force (F) on a charge q moving with thevelocity v)(HvqFµ×=(4.5)The magnetic field strength is expressed in units of ampere per metre (A/m)4.1.19measurement rangethe measurement range is the interval of operation of the measurement system, which is bounded bythe lower and the upper detection limits4.1.20mobile phonefor the purpose of this standard, the term “Mobile Phone” covers any equipment within the scope ofthis standard4.1.21multi-banda multi-band mobile phone is operating in one single radiocommunication system (mode) in variousfrequency bands, e.g., GSM 900 and GSM 1 8004.1.22multi-modea multi-mode mobile phone is operating with various radiocommunication systems, e.g., GSM andDECTSIST EN 50361:2002

- 9 -EN 50361:20014.1.30skin depththe skin depth is defined as the distance from the boundary of a medium to the point at which the fieldstrength or induced current density have been reduced to 1/e of their boundary values. Skin depth isexpressed in meters (m)4.1.31Specific Absorption Rate (SAR)the time derivative of the incremental electromagnetic energy (dW) absorbed by (dissipated in) anincremental mass (dm) contained in a volume element (dV) of given mass density (ρ)==dVdWdtddmdWdtdSARρ(4.8)SAR is expressed in units of watts per kilogram (W/kg)NOTE SAR can be calculated by:SAR=σEi2ρ(4.9)SAR=cidTdt t=0(4.10)whereEi:rms value of the electric field strength in the tissue in V/mσ:conductivity of body tissue in S/mρ:density of body tissue in kg/m3ci:heat capacity of body tissue in J/kg KdTdt t=0initial time derivative of temperature in body tissue in K/s4.1.32wavelength (λλλλ)the wavelength (λ) of an electromagnetic wave is related to the frequency (f) and speed of light (c) bythe expression c=f. In free space the velocity of an electromagnetic wave is equal to the speedof light5 Measurement system specificationsThe measurement system is composed of the phantom, the SAR measurement equipment, thescanning system and the mobile phone holder.5.1 General requirementsThe test shall be performed using a miniature probe that is automatically positioned to measure theinternal E-field distribution in a phantom model representing the human head exposed to the EMfields produced by mobile phones. From the measured E-field values, the SAR distribution and themaximum mass averaged SAR value shall be calculated.The test shall be performed in a laboratory conforming to the following environmental conditions:• the ambient temperature shall be in the range of 15 °C to 30 °C and the variation shallnot exceed ± 2 °C during the test;SIST EN 50361:2002

The phantom shall be made frommaterial with dielectric properties similar to those of head tissues.
To enable field scanning within it,the material shall be liquid contained in a head and neck shaped shell model.
The shell model actsas a shaped container and shall be as unobtrusive as possible. The hand shall not be modelled (seeannex A).5.2.2 Phantom shape and sizeThe phantom shape is based on the size and dimensions of the 90 percentile large adult malereported in a 1989 anthropomorphic study and has been adapted to represent the flattened ear of amobile phone user (see annex A). A physical representation of these requirements is shown inFigure 1.a and Figure 1.b.Figure 1.aFigure 1.bFigure 1 - Picture of the phantomThe Specific Anthropomorphic Mannequin (SAM) shall be used for SAR measurements. CAD files ofthe inner surface (SAM_in) and outer surface (SAM_out) of the reference phantom used in thisstandard are publicly available in 3D-CAD formats including 3D-IGES and DXF on CD-ROM.5.2.3 Phantom shellThe shell of the phantom shall be made of low loss and low permittivity material: tan(δ) ≤ 0,05 and ε ≤ 5. The thickness of the phantom is defined in the CAD files and the tolerance shall be ± 0,2 mm inthe area defined in the CAD files (where the phone touches the head).SIST EN 50361:2002

- 11 -EN 50361:2001Reference points on the phantom:The probe positioning shall be defined in relation to three well defined points on the phantom. Thesepoints R1, R2 and R3 shall be used to calibrate the positioning system. Three other points, M formouth, LE for left ear and/or RE for right ear (maximum acoustic coupling), shall be defined on thephantom(s) (see Figure 2). These points shall be used to allow reproducible positioning of the mobilephone in relation to the phantom.These points are specified in the CAD files.5.2.4 Liquid material propertiesThe dielectric properties of the liquid material required to fill the phantom shell shall be:εr = 46,52 – 0,006 f(MHz) + 1,59x10-6 f(MHz)2 –1,40x10-10 f(MHz)3(5.1)σ (S/m) =
0,805 4 + 0,000 15 f(MHz) + 4,12x10-8 f(MHz)2 + 2,87x10-11 f(MHz)3(5.2)Table 1 - Dielectric properties of the liquid materialFrequency(MHz)εεεεrσσσσ (S/m)300450,85450440,88900420,991 450411,201 800401,382 450391,843 000392,40The measured dielectric properties of the liquid shall be used in SAR calculations rather than thetheoretical values defined in Equation 5.1 and Equation 5.2 and shown in Table 1. Examples ofrecipes for liquids defined in Table 1 used at mobile communication frequencies are proposed inannex A.5.3 Specifications of the SAR measurement equipmentThe measurement equipment shall be calibrated as a complete system. The probe shall be calibratedtogether with the amplifier, measurement device and data acquisition system. The measurementequipment shall be calibrated in each tissue equivalent liquid at the appropriate operating frequencyand temperature according to the methodology defined in annex B.The minimum detection limit shall be lower than 0,02 W/kg and the maximum detection limit shall behigher than 100 W/kg. The linearity shall be within ± 0,5 dB over the SAR range from 0,02 to100 W/kg. The isotropy shall be within ± 1 dB. Sensitivity, linearity and isotropy shall be determinedin the tissue equivalent liquid. The response time shall be specified.In order to meet these requirements, it is recommended that the length of the individual sensingelements in the E-field probe shall not exceed 5 mm and that the outside dimension of the protectivecover shall not exceed 8 mm.If the measured signal is a pulsed signal, e.g., a TDMA frame, the integration and averaging time ofthe SAR measurement equipment (based on rms-detection) shall be able to yield results reproducibleto within ± 5 %.SIST EN 50361:2002

- 13 -EN 50361:2001The purpose of the simplified performance check is to verify that the system operates within itsspecifications. The simplified performance check is a simple test of repeatability to make sure that thesystem works correctly during the compliance test. The simplified performance check shall beperformed in order to detect possible drift over short time periods and other errors in the system, suchas:• changes in the liquid parameters, e.g., due to water evaporation or temperature change,• component failures,• component drift,• operator errors in the set-up or the software parameters,• adverse conditions in the system, e.g., RF interference.The simplified performance check shall be carried out according to annex D. It shall be ameasurement of the 10 g averaged SAR using a simplified set-up with a dipole source. Thecomponents and procedures in the simplified performance check are the same as those used for thecompliance tests. The simplified performance check shall be performed prior to compliance tests andthe result shall be within ± 10 % of the target value. The target value shall be determined in thesystem itself, e.g., after the system validation check. The simplified performance check shall beperformed at a central frequency of each transmitting band of the mobile phone.6.1.3 Preparation of the mobile phone under testThe tested mobile phone shall use its internal transmitter. The antenna(s), battery and accessoriesshall be those specified by the manufacturer. The battery shall be fully charged before eachmeasurement and there shall be no external connections.The output power and frequency (channel) shall be controlled using an internal test program or by theuse of appropriate test equipment (base station simulator). The mobile phone shall be set to transmitat its highest output peak power level allowed by the system. If a wireless link is used, an antennashall be connected to the output of the base station emulator. The antenna shall be placed at least 50cm from the phone. The signal emitted by the emulator at antenna feed point shall be lower than theoutput level of the phone by at least 30 dB.6.1.4 Position of the mobile phone in relation to the phantomThe mobile phone shall be tested in the “cheek” and “tilted” positions on left and right sides of thephantom.Definition of the “cheek” position:a) position the device with the vertical centre line of the body of the device and thehorizontal line crossing the centre of the ear piece in a plane parallel to the sagittalplane of the phantom ("initial position" see Figure 2). While maintaining the device inthis plane, align the vertical centre line with the reference plane containing the three earand mouth reference points (M, RE and LE) and align the centre of the ear piece withthe line RE-LE;b) translate the mobile phone box towards the phantom with the ear piece aligned with theline LE-RE until the phone touches the ear. While maintaining the device in thereference plane and maintaining the phone contact with the ear, move the bottom of thebox until any point on the front side is in contact with the cheek of the phantom or untilcontact with the ear is lost.SIST EN 50361:2002

- 15 -EN 50361:20016.2 Tests to be performedTests shall be performed with both phone positions described in 6.1.4., on the left and right sides ofthe head and using the centre frequency of each operating band. Then the configuration giving rise tothe maximum mass-averaged SAR shall be used to test the low-end and the high-end frequencies ofthe transmitting band. If the mobile phone has a retractable antenna, all of the tests described aboveshall be performed both with the antenna extended and with it retracted. When considering multi-mode and multi-band mobile phones, all of the above tests shall be performed in each transmittingmode/band with the corresponding maximum peak power level.Figure 4 - Block diagram of the tests to be performedSIST EN 50361:2002

- 17 -EN 50361:20016.4.4 Searching for the maximaThe cubic volumes shall be moved on the inner surface of the phantom, in the vicinity of the localmaximum SAR, according to the rules given in annex C.The cube with the highest local maximum SAR shall not be at the edge of the scanning volume. If thisis found to be the case, the scanning volume shall be shifted and the measurements shall berepeated.7 Uncertainty assessment7.1 General requirementsThe assessment of uncertainty in the measurement of the SAR values produced by mobile phonesshall be based on the general rules provided by the IEC “Guide to the expression of uncertainty inmeasurement”, Ed. 1, 1995.Type A as well as Type B evaluation of the standard uncertainty shall be used.When a Type A analysis is performed, the standard uncertainty ui shall be derived from the estimatefrom statistical observations. When Type B analysis is performed, ui comes from the upper +a andlower −a limits of the quantity in question, depending on the distribution law defining2)(−+−=aaa, then:− Rectangular law:3aui=− Triangular law:6aui=− Normal law:kaui=where k is a coverage factor− U-shaped (asymmetric):2aui=7.2 Components contributing to uncertainty7.2.1 Contribution of the measurement system7.2.1.1 Calibration of the measurement equipmentA protocol for the evaluation of sensitivity (or calibration) is given in annex B including an approach touncertainty assessment. The uncertainty in the sensitivity shall be evaluated with assuming a normalprobability distribution.7.2.1.2 Probe isotropyThe isotropy of the probe shall be measured according to the protocol defined in annex B. Theuncertainty due to isotropy shall be evaluated with a
rectangular probability distribution.22].[]).[1(isotropycalHemisphericisotropyAxialcErrorIsotropyTotalii+−=If the probe orientation is essentially normal to the surface (within ± 30º) during the measurement,then ci = 0,5 otherwise ci = 1.SIST EN 50361:2002

These effects depend on the probe size and can bequantified as a function of the distance from the surface using the wave guide calibration set-up orplane wave exposure (see annex B). Having been quantified, the effects can be compensated for inorder to minimise any errors introduced.7.2.1.5.2 EvaluationAssuming a linear model and minimal skin depth, as would represent the worst-case, the maximumerror in the integration arising from this effect can be determined as:Error [%] = [Uncertainty of the boundary effect at dbe in %]2sdddstepbe+wheredbeis the distance between the surface and the closest measurement point used for thecube averaging processdstepis the separation between the first and second closest points, assuming that theboundary effect at that location is negligiblesdis the minimum skin depth, i.e., sd = 14 mm at 3 GHz.If the uncertainty of the boundary effect compensation cannot be determined, then the boundaryeffect shall be used in the above formula.7.2.1.6 Measurement deviceThe uncertainty contributed by the measurement device, e.g., voltmeter, shall be assessed withreference to its calibration certificates. The uncertainty due to the measurement device shall beevaluated assuming a normal probability distribution.SIST EN 50361:2002

- 19 -EN 50361:20017.2.1.7 Response timeResponse time shall be evaluated according to the protocol defined in annex B. The uncertaintyarising from the response time shall be neglected if the probe is stationary for a time period greaterthan twice the response time before the measured SAR is logged.7.2.1.8 Noise7.2.1.8.1 DefinitionThis is the signal detected by the measurement system even if the phone is not transmitting. Thesources of these signals include RF noise, ELF noise (lighting systems, the scanning system,grounding of the laboratory power supply, etc.), electrostatic effects (movement of the probe, peoplewalking, etc.) and other effects (light detecting effects, temperature, etc.)7.2.1.8.2 EvaluationThe noise level shall be determined by three different coarse scans with the RF source switched off.None of the evaluated points shall exceed 0,02 W/kg.
This test shall be repeated periodically(preferably every second month). Within this constraint, the uncertainty due to noise shall beneglected.7.2.1.9 Integration timeThe integration time may introduce additional error if the mobile phone is not emitting a continuouswave (CW) signal. This uncertainty depends on the signal characteristics and must be evaluated priorto any SAR measurements. If a non-CW signal is used, then the uncertainty introduced must be takeninto account in the global uncertainty assessment. The uncertainty due to integration time shall beevaluated assuming it has a rectangular probability distribution.Example of evaluation for a GSM signal :For an integration time of intt, if 2 pulses are missed, this induces the following uncertainty:int3106,4.2txu−=7.2.2 Contribution of mechanical constraints7.2.2.1 Scanning systemThe mechanical constraints of the scanning system introduce uncertainty to the SAR measurementsthrough the accuracy and repeatability of positioning. These parameters shall be assessed withreference to the scanning system’s specifications. The uncertainty contribution dss to the averagedSAR value (rectangular distribution) is then calculated based on the minimum skin depth sd, i.e.,sd = 14 mm at 3 GHz and first-order approximation:Error SAR [%] = 2100sddssSIST EN 50361:2002

- 21 -EN 50361:20017.2.3.3 Liquid permittivityThe uncertainty due to the liquid permittivity arises from two different sources. The first source oferror is the deviation of the liquid conductivity from its target value (max. ± 5 %) and the secondsource of error arises from the measurement procedures used to assess permittivity. The uncertaintyshall be assessed using a rectangular probability. For 10 g averaging, the maximum weightingcoefficient for SAR is 0,5.7.2.3.4 Drifts in output power of the phone, probe, temperature and humidityThe drifts due to the electronics of the phone and the measurement equipment, as well astemperature and humidity, are controlled by the first and last step of the measurement processdefined in 6.3 and the resulting error is less than ± 5 %. The uncertainty shall be evaluated assuminga rectangular probability distribution.7.2.3.5 Perturbation of the environmentThe perturbation of the environment results from various contributing factors:• reflection of waves in the laboratory,• influence of the EM properties of the phantom shell and the mobile phone holder,• background level of EM fields.The error is usually of ± 3 % and the uncertainty shall be evaluated assuming a rectangularprobability distribution.7.2.4 Contribution of post-processingThis is the uncertainty caused by the implemented extrapolation, integration and averaging procedureassuming the local SAR are accurately measured at their correct positions.7.2.4.1 Extrapolation and interpolation algorithmsThe uncertainty due to the extrapolation and interpolation algorithms shall be evaluated assuming arectangular probability distribution. The relative uncertainty is evaluated using the following formula(see annex C):refreferpextraperpolextraSARSARSARU−=int/int/.100%Four sets of 3D referenc
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