MIC Issues Draft Circular on SAR for Mobile Phones！

Laura Cortes

The Ministry of Information and Communication (MIC) of Vietnam issued a Draft Circular which promulgates national technical regulations on Specific Absorption Rates (SAR) for Mobile Phones on April 25, 2024. The Draft Circular will come into effect on July 1, 2025, at which point imported and domestically produced Mobile Phones must meet the requirements in the National Technical Regulation QCVN 134:2024/BTTTT prior to be sold in Vietnam. The Draft Circular? will be open for comments until June 25, 2024.

English version of the draft:

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NATIONAL TECHNICAL REGULATIONS

ABOUT INDIVIDUAL ABSORPTION LEVELS

FOR MOBILE PHONES

1. GENERAL PROVISIONS

1.1. Scope

This regulation regulates limits and methods for measuring absorption levels specific to mobile phones.

HS codes are specified in Appendix A.

1.2. Applicable subjects

This technical regulation applies to Vietnamese and foreign agencies, organizations and individuals engaged in manufacturing, importing, trading and exploiting equipment within the scope of this Regulation. Vietnamese territory.

1.3. Reference documents

IEC 62209-1528:2020 Measurement procedure for the assessment of specific absorption rate of human exposure to radio frequency fields from hand-held and body-worn wireless communication devices - Human models, instrumentation and procedures (Frequency range of 4 MHz to 10 GHz) .

Safety management in radio frequency radiation - Part 1: Maximum exposure levels in the frequency range from 3 kHz to 300 GHz”.

FCC 47 CFR § 2.1093 - Radiofrequency radiation exposure evaluation: portable devices.

1.4. Explanation of words

1.4.1 Accessories

As an optional component or attachment that can be used with the device under test (DUT)

EXAMPLE 1: Accessories used to hold, attach or carry, wear or attach the device as well as for any other specific use on the user's body (e.g. belt clips, neck straps arm or any type of body strap or device lanyard for a necklace).

EXAMPLE 2: Electronic accessories to perform specialized tasks or provide additional features (e.g. GPS module, external printer, MP3 player, camera or viewer ).

EXAMPLE 3: Electronic accessories that provide audio or video input or output (e.g., headphones , microphone, camera).

EXAMPLE 4: Accessories that provide enhanced RF capabilities for the device (e.g., original antenna, replacement antenna, or auxiliary antenna).

EXAMPLE 5: Batteries and associated DC power components.

EXAMPLE 6: Combination of accessories, where two or more of the above accessories are combined in one part.

1.4.2. Isotropic axis

The maximum deviation of the SAR is measured when the probe is rotated around its main axis while being exposed to waves impinging from the direction coincident with the main axis.

1.4 .1.4. Basic limit

Human exposure limits to compliance with time-varying electric, magnetic, and electromagnetic fields measured within the body based on established adverse health effects.

NOTE 1: Within the scope of this document, the physical quantity used as a fundamental limitation is the quantity determining the specific absorption rate (SAR).

1.4.4 Wearable devices

The device contains one or more wireless transmitters or transceivers that are placed close to a person's body or limbs (excluding the head) by means of a carrying accessory to support activities according to the intended use.

NOTE 1: This document uses the term body-worn synonymously with the term body-worn, as used in previous editions.

1.4.5 Body support equipment

The device contains one or more wireless transmitters or transceivers , whose intended use includes transmitting signals by holding any part of the device directly on the user's body.

1.4.6 Edge effects

The change in sensitivity of an electric field probe when the probe is placed close (smaller than the probe diameter) to the boundary of the environment.

NOTE 1: This effect is due to distortion of the scattered field at the probe tip due to the nearby virtual dielectric surface. This effect can be compensated if the orientation of the probe with respect to the virtual surface is known.

1.4.7 Cables

The type of wire necessary for the function of the device for the set up operation.

1.4.8 Radio frequency channel

RF Channel

Clearly divide the transmit frequency range according to the operating parameters of an individual wireless technology.

NOTE 1: The number of RF channels and corresponding channel bandwidths may vary between individual wireless technologies.

For the purposes of this document, SAR measurements are performed at specified channels; for example, the high, middle and low channels of the broadcast band.

1.4.9 Conducted capacity

Power is supplied by the device's power amplifier to the appropriate load.

1.4.10 Exposure assurance

The psSAR assessment, including the measurement uncertainty specified herein, results in slightly higher than would be expected to occur on the head or body of the majority of users during intended use. wireless device destination.

1.4.11 Constant envelope mode

Transmission mode in which the signal amplitude does not change with time.

1.4.12 Correlation signals

The electromagnetic field, which combines the separate signal waveforms, provides a time-domain correlation interval that is non-zero at any instant in time.

NOTE 1: Details are specified in IEC TR 62630 [1].

1.4.13 Desktop devices

Equipment placed or mounted on a reading table, table or similar support structure, with an antenna designed to operate at a distance or closer than 200 mm from the human body.

1.4.14 Equipment rack

A fixture made of low-loss insulating material used to hold the test device at the test location during SAR measurements.

1.4.15 Equipment tested

DUT

The device contains one or more wireless transmitters or transceivers that are tested according to the methods of this document.

NOTE 1: The device under test can be further classified as body-worn, body-supported, table-top, front-facing, hand- held , arm-worn, clothing-integrated, or general equipment.

1.4.16 Usage coefficient

The proportion of time that the transmitter transmits during a specified period of time.

1.4.17 Rapid SAR test

Use special techniques, methods or algorithms to reduce SAR measurement time compared to full SAR testing.

NOTE 1: Type 1 rapid SAR testing uses hardware that complies with all the requirements of this document for full SAR testing. However, it uses testing methods that are faster than following full SAR testing methods.

NOTE 2: Type 2 rapid SAR testing uses hardware and testing procedures that do not comply with the requirements of this document for full SAR testing.

1.4.18 Band

The emission frequency range is associated with a defined wireless operating mode.

NOTE 1 Frequency ranges are often referred to using round numbers, however the actual frequency distribution may differ. For example, the GSM 900 MHz band actually uses 880 MHz to 915 MHz and 925 MHz to 960 MHz.

1.4.19 Equipment used in front of you

handheld device contains one or more wireless transmitters or transceivers that operate in close proximity to the face.

NOTE 1: Types of devices used in front of the face include PTT devices (two-way radios) and devices equipped with optical cameras.

1.4.20 Full SAR testing

Use specific methods, procedures and hardware that fully comply with all requirements specified in this document, except those specified in 7.9.2

1.4.21 Head-mounted devices

A device containing one or more wireless transmitters or transceivers placed near a person's head or neck by an accessory, to facilitate the intended use of the device.

handheld devices .

1.4.22 Isotropic hemisphere

Maximum deviation of SAR measured when rotating the probe about its principal axis while simultaneously being exposed to a reference wave impinging from the half-space in front of the head, at different angles of incidence relative to the probe's axis.

1.4.23 Server

The system is operated by a wireless device or module during testing to provide broadcast functionality according to its intended use.

1.4.24 Intended use

Conditions of use for which the product is designed to fully accommodate available functions, according to specifications, instructions and information provided by the manufacturer in the user manual.

Wearable devices

The device contains one or more wireless transmitters or transceivers , intended to be worn on the user's arm or leg while transmitting.

NOTE 1: Types of limb-worn devices include wrist-, ankle- and forearm-worn devices. Some jurisdictions specify different requirements for devices worn on limbs away from the wrist or ankle.

1.4.26 Linearity error

The maximum deviation of a measurement from the expected linear fit within the measurement range .

1.4.27 Drift measurement

Continuous or gradual change of a measured quantity over time due to changes in the measurement characteristics of the measuring medium.

1.4.28 Measurement uncertainty

1.4.28.1 Uncertainty assessment

evaluates uncertainty by statistical analysis of series of observations (measurements).

1.4.28.2 Uncertainty assessment

assessment of uncertainty by methods other than statistical analysis of series of observations (measurements)

1.4.28.3 Standard uncertainty

The estimated standard deviation of a measurement result, by taking the positive square root of the estimated variance.

1.4.28.4 Combined uncertainty

The estimated standard deviation of a measurement result obtained by combining the individual measurement uncertainties of both Type A and Type B evaluations when using the usual “root sum of squares” method for combining the deviations standard is obtained by taking the positive square root of the estimated variances.

1.4.28.5 Expanded uncertainty

A definite quantity about the expected result of a measurement consisting of an arrangement of values within a specified confidence interval that can be reasonably attributed to the quantity being measured.

1.4.29 Multi-band

< wireless communication device > capable of operating in multiple frequency bands.

1.4.30 Operating mode

Wireless protocol or standard when used by one device to communicate with another terminal or device over a wireless network.

NOTE 1: The operating mode includes all parameters for establishing wireless communication. Including specific parameters but not limited to: communication standards, frequency bands, channels, signal modulation, communication protocols, data rates, bandwidth, number and location of time slots as well as the number and location of resource blocks. Some operating modes do not have some of these parameters.

NOTE 2: Current terminals may have multiple operating modes for individual or simultaneous transmission.

Examples of operating modes include wireless protocols such as GSM, EDGE, , GPRS, WCDMA, LTE, 5G NR, Bluetooth? 1 and Wi-Fi? 2 . Multiple operating modes can transmit in one or more frequency bands, for example, the DUT can support multiple wireless technologies within a single frequency band and also allow multiple wireless transmission modes, such as GSM, GPRS, EDGE or WCDMA and HSPA or 5G NR.

1.4.31 Output power

The power at the output of an RF transmitter when the antenna or load has the same input impedance as the antenna connected to it.

1.4.32 Primary peak SAR value

The maximum area interpolated SAR value determined in a range area scan measurement .

1.4.33 Secondary peak SAR value

rangefinder measurement , the interpolated peak SAR value is less than the primary peak SAR value.

1.4.34 Average peak SAR value in space

psSAR

Peak SAR values are averaged within an internal region based on a defined average volume. For example, any 1g or 10g of string has a cube shape.

NOTE 1: In this document, the terms psSAR (per 1g or 10g) and the terms 1g SAR and 10g SAR are used interchangeably.

1.4. 35 Penetration depth

The depth at which the SAR of an incident plane wave link, penetrating a uniformly attenuating medium, reduces to 1/e 2 of its value just below the surface of the medium.

NOTE 1: Normally, for plane waves incident on a flat half-space, through field E, the penetration depth δ is calculated as:

With:

ω??? is the angular frequency

μ0?? is the vacuum magnetic permeability, expressed in henry per meter;

ε0?? is the electropermeability of vacuum, in farads per meter;

εr'??? is the relative dielectric permittivity of the attenuating medium, without units;

σ??? is the electrical conductivity of the attenuating medium, measured in siemens per meter.

1.4.36 Mannequin

A physical equivalent of a human body consisting of tissue-like material with electrical insulating properties is specified herein.

1.4.37 Ear flap

Cartilage protruding from the ear , including the inner ear, lobule and outer ear.

1.4.38 Power control algorithm

DUT protocol for setting and adjusting the maximum output power of a transmitter over a specific averaging period.

1.4.39 Productivity variation

Output power amplitude between DUT production models when set to maximum output level.

1.4.40 Push-to-talk device

The handheld radio transceiver allows the user to use a mechanical switch to switch between radio transmission and reception (simple use mode).

For example: two-way radio

1.4.41 Isotropic probe

Characteristic related to the response level of an electric field probe or a magnetic field probe independent of the polarization and direction of propagation of the incident wave.

Note 1 to entry: See also axial isotropic (1.4.2) and hemispherical isotropic (1.4.25)

1.4.42 Proximity sensor

A capacitive sensor or combination of sensors in the DUT is used to detect user proximity for the purpose of limiting transmitter power to ensure compliance with RF exposure limits.

1.4.43 Electronic indicator device

The measurement system component connects to the E-field probe and provides analog-to-digital conversion of the measurement values to the measurement system processor.

1.4. 44 Response time

The time required for the measuring device to reach 90% of the final value after one step variation of the input signal.

1.4.45 Scanning system

The automatic positioning system is capable of placing measuring probes at specified locations according to the requirements of this document.

1.4.46 Sensitivity

The ratio of the magnitude of the system response (e.g., voltage) to the magnitude of the quantity being measured (e.g., the square of the electric field strength).

1.4.47 Separation distance

Distance between the device under test and the outer surface of the dummy.

NOTE 1 Separation distance describes the distance during intended use.

1.4.48 SAR specific absorption level

A measure of the rate at which the human body absorbs energy when exposed to radio frequency electromagnetic fields.

NOTE 1 SAR in a tissue-equivalent environment can be determined by the rate of heat rise or by E-field measurements, according to the following equations:

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1.4.48 Test configuration

The set of DUT parameters applicable to SAR measurements, including the location of the DUT used on the dummy, the configuration in which the DUT is used (e.g., antenna location), and the operating mode.

1.4.49 Average SAR over the period

TPAS

SAR is averaged over a specified averaging period when applying a power control algorithm.

1.4.50 Average SAR over time

SAR is measured over an integration time long enough to ensure stable results on the power factor and other characteristics of the modulated signal.

1.4.51 Adjustment specifications

The specification's output power tolerance adjusts when setting the DUT model to transmit at maximum output power.

1.4.52 TX coefficient

Ratio of the average output power to the peak output power of a DUT over a specified average time period.

1.5. Abbreviated symbols and terms

1.5.1 Physical quantity

NOTE: In this document, temperature is determined in degrees Celsius, calculated as: T (°C) = T( K) – 273.15 K.

1.5.2. Constants

1.5.3 Abbreviated terms

2. TECHNICAL REGULATIONS

Limits for specific absorption in the frequency range 4 MHz to 10 GHz are according to the table below

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3. MEASUREMENT METHOD

3.1. overview

Complies with requirement 7.1 of IEC 62209-1528:2020

3.2. Prepare for testing

3.2.1. Tissue and system simulation environment

Complies with requirement 7.2.1 of IEC 62209-1528:2020

3.2.2. Wireless connections to the test sample

Complies with requirement 7.2.2 of IEC 62209-1528:2020

3.2.3. Operating mode of the test sample

Complies with requirement 7.2.3 of IEC 62209-1528:2020

3.2.4. Location of the test sample

Complies with requirement 7.2.4 of IEC 62209-1528:2020

3.2.5. Antenna configuration

Complies with requirement 7.2.5 of IEC 62209-1528:2020

3.2.6. Options and accessories

Complies with requirement 7.2.6 of IEC 62209-1528:2020

3.2.7. Test sample and coefficients

Complies with requirement 7.2.7 of IEC 62209-1528:2020

3.2.8. Operating frequency of the test sample

Complies with requirement 7.2.8 of IEC 62209-1528:2020

3.3. Tests need to be performed

3.3.1. overview

Complies with requirement 7.3.1 of IEC 62209-1528:2020

3.3.2. Basic tests

Complies with requirement 7.3.2 of IEC 62209-1528:2020

3.4. Testing procedure

3.4.1. overview

Complies with requirement 7.4.1 of IEC 62209-1528:2020

3.4.2. Full SAR testing procedure

Complies with requirement 7.4.2 of IEC 62209-1528:2020

3.4.3. Scan test

Complies with requirement 7.4.3 of IEC 62209-1528:2020

3.4.4. Test when the test sample has multiple antennas or multiple transmitters

Complies with requirement 7.4.4 of IEC 62209-1528:2020

3.5. Data processing

3.5.1. Interpolation

Complies with requirement 7.5.1 of IEC 62209-1528:2020

3.5.2. Extrapolation

Complies with requirement 7.5.2 of IEC 62209-1528:2020.

3.5.3. Determine the average volume

Complies with requirement 7.5.3 of IEC 62209-1528:2020

3.5.4. Determine the maximum value

Complies with requirement 7.5.4 of IEC 62209-1528:2020

3.6. Average SAR value over the time period

3.6.1. overview

Complies with requirement 7.6.1 of IEC 62209-1528:2020

3.6.2. Conduction capacity

Complies with requirement 7.6.2 of IEC 62209-1528:2020

3.6.3. Test configurations

Complies with requirement 7.6.3 of IEC 62209-1528:2020

3.6.4. Absorption conditions and test locations

Complies with requirement 7.6.4 of IEC 62209-1528:2020

3.6.5. Average SAR over time with simultaneous transmission

Complies with requirement 7.6.5 of IEC 62209-1528:2020

3.6.6. Evaluate the generation coefficient

Complies with requirement 7.6.6 of IEC 62209-1528:2020

3.6.7. SAR testing

Complies with requirement 7.6.7 of IEC 62209-1528:2020

3.6.8. Measurement uncertainty with SAR test averaged over time period

Complies with requirement 7.6.8 of IEC 62209-1528:2020

3.7. Tested using the sensor

3.7.1. overview

Complies with requirement 7.7.1 of IEC 62209-1528:2020

3.7.2. Determine the sensor activation distance

Complies with requirement 7.7.2 of IEC 62209-1528:2020

3.7.3. Determine the sensor's operating area

Complies with requirement 7.7.3 of IEC 62209-1528:2020

3.7.4. SAR testing using sensors

Complies with requirement 7.7.4 of IEC 62209-1528:2020

3.8. Correct the SAR value

3.8.1. overview

Complies with requirement 7.8.1 of IEC 62209-1528:2020

3.8.2. SAR correction formula

Complies with requirement 7.8.2 of IEC 62209-1528:2020

3.8.3. Uncertainty of the correction formula

Complies with requirement 7.8.3 of IEC 62209-1528:2020

3.9. Methods to shorten testing time

3.9.1 Overview

Complies with requirement 7.9.1 of IEC 62209-1528:2020

3.9.2 Rapid SAR test

Complies with requirement 7.9.2 of IEC 62209-1528:2020

3.9.3 Abbreviated SAR test

Complies with requirement 7.9.3 of IEC 62209-1528:2020

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4. MANAGEMENT REGULATIONS

Related radio devices within the scope of regulation specified in Article 1.1 must comply with the technical regulations in this Regulation.

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5. RESPONSIBILITIES OF INDIVIDUAL orGANIZATIONS

Relevant organizations and individuals are responsible for implementing the regulations on declaration of conformity of equipment within the scope of this Regulation and are subject to inspection by state management agencies according to current regulations.

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6. IMPLEMENTATION orGANIZATION

6.1. The Department of Telecommunications, the Department of Radio Frequency, and the Departments of Information and Communications are responsible for organizing and guiding the deployment and management of radio equipment according to this Regulation.

6.2. In case the regulations stated in this Regulation are changed, supplemented or replaced, the provisions in the new document shall comply.

6.3. During the implementation of this standard, if any problems or difficulties arise, relevant organizations and individuals should report in writing to the Ministry of Information and Communications (Department of Science and Technology). for guidance and solutions./.

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Source:

https://mic.gov.vn/van-ban-phap-luat/du-thao/2190.htm