SAR – RED / ETSI / FCC

What Is SAR — RED?

SAR (specific absorption rate) test measures the absorbed RF power per unit mass caused by the transmitter in a phantom containing liquid equivalent to human tissue; It is a human exposure experiment in which head, trunk and limb usage scenarios are evaluated.

Purpose of SAR — RED

The purpose is to verify that the device does not exceed human exposure limit values; It is a mandatory health requirement for radio equipment to be placed on the market.

Which Products Is SAR — RED Applied To?

Smartphones and tablets
body worn devices
Laptops and portable computers
Cellular modules used in close range

In Which Sectors Is SAR — RED Used?

TelecommunicationsElectronicsSoftwareCyber Security

Standards Related to SAR — RED

REDEU radio equipment directive test
ETSIEuropean telecommunications standards test
FCCUS radio and EMC regulations test

SAR — RED Conditions

Fantom: Standard defined head and straight body phantoms
Tissue equivalent fluid: Dielectric properties defined according to test frequency
Measurement: Volumetric scanning with a calibrated isotropic E-field probe; 1 g and/or 10 g average
separation distance: Defined according to the usage scenario; is declared

Equipment for SAR — RED

Robotic SAR measurement system and phantoms
Calibrated isotropic E field probe
Tissue equivalent liquid and dielectric measurement setup
System verification dipoles

Sample Requirements for SAR — RED

Device must be at maximum power setting and final configuration
All bands and usage scenarios must be declared
Battery must be fully charged and stable
Separation distance should be consistent with the user manual

Duration of SAR — RED

Typically 2–5 weeks depending on the number of tapes and scripts.

SAR — RED Procedure

1Tissue equivalent liquid dielectric properties are verified.
2The measurement system is checked with the system verification dipole.
3The device is placed in the relevant position at maximum power.
4The area is scanned and the maximum SAR zone is found.
51g/10g average SAR is calculated by volumetric scanning.
6Repeats for all bands and scenarios.

SAR — RED Acceptance Criteria

Acceptance criteria are valid exposure limits: In Europe, defined limit values of 10 g average are used, in the USA, defined limit values of 1 g average are used.

Evaluation of Results

Europe and the USA use different mean mass and limit values; A result for one market cannot be directly transferred to another. The declared separation distance must be exactly consistent with the information in the user manual, otherwise the conformity is invalid.

SAR — RED Report

Applied standards
Device, tapes and usage scenarios
Liquid dielectric verification and system inspection
SAR results for each scenario
Declared separation distance
Measurement uncertainty

Accreditation

EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.

Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.

Scope and authorisations

Related Regulations

Radio Equipment Directive 2014/53/EU Article 3(1)(a) (health)
FCC RF exposure guidelines

RF and Wireless Testing — What Does This Testing Field Cover?

The section below describes the field that the SAR test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.

RF and wireless testing shows that a device containing a radio uses the spectrum correctly and operates within the limits the relevant legislation allows. This family is a separate body of work from EMC: EMC addresses unwanted interference, whereas here INTENTIONAL emission is assessed.

Spectrum is a public and limited resource, and this determines the legal character of the field. A device spilling outside its permitted band or emitting excess power is not merely a technical defect but a violation that disrupts someone else's service. Radio conformity is therefore policed more strictly than other test fields and markets maintain their own national regimes.

Measurements run separately on the transmitter and receiver sides. On the transmitter side, output power, occupied bandwidth, frequency error, unwanted emissions, adjacent channel power and the power envelope are measured. On the receiver side, sensitivity, selectivity, blocking and spurious response rejection are assessed. The receiver side is often neglected, but in some bands it is a regulatory requirement.

Access protocol specific behaviours are a third axis: listen before talk (LBT), duty cycle, dynamic frequency selection (DFS) and transmit power control (TPC). These mechanisms enable spectrum sharing and it must be shown that they work correctly.

HUMAN EXPOSURE is the fourth axis and one of the most commercially critical. For devices used close to the body, SAR (specific absorption rate) is measured; for devices used at a distance, a field strength assessment is made. Limits and measurement methods vary by market; the same device is assessed separately for Europe and the United States.

Market regimes are decisive in this family and do not substitute for one another: the Radio Equipment Directive and ETSI harmonised standards in Europe, FCC authorisation in the United States (through a TCB for intentional radiators), ISED in Canada, MIC in Japan, KC in South Korea and SRRC in China each carry their own set of requirements. The same device requires a separate file for each market, and some markets impose a local representative or local testing requirement.

Module integration is the subject that raises the most questions in the field. Using a certified radio module does not automatically make the device compliant. A module certificate is valid for a defined antenna, a defined supply and defined conditions of use; if the antenna changes, the layout changes or the module is operated at a different power level, reassessment is required.

The presence of several radios in the same device (Wi-Fi + Bluetooth + cellular + NFC) gives rise to a simultaneous transmission assessment: SAR and unwanted emission measurements are made for the worst case in which the radios operate together.

Method groups in this field

Transmitter measurements
Output power, occupied bandwidth, frequency error, unwanted emissions, adjacent channel power, power spectral density.
Receiver measurements
Sensitivity, selectivity, blocking, spurious response rejection.
Spectrum sharing mechanisms
Verification of listen before talk, duty cycle, dynamic frequency selection and transmit power control.
Human exposure
SAR measurement (handheld and body-worn devices), field strength assessment, multi-radio scenarios.
Protocol conformity
Cellular network conformity testing, Bluetooth and Wi-Fi certification testing, GNSS performance.
Antenna measurements
Gain, radiation pattern, efficiency and total radiated power (TRP) measurements.

Commonly confused in this field

Using a certified module does not automatically make the device compliant; if the antenna, layout or power level changes, reassessment is required.
An FCC file does not replace a CE file; each market operates its own regime.
Receiver side measurements are a regulatory requirement in some bands; measuring only the transmitter produces an incomplete file.
SAR limits and measurement methods differ by market; a result in one market does not carry over to another.
For devices carrying several radios the simultaneous transmission scenario must be assessed; measuring them individually is not sufficient.
Some markets impose local testing or a local representative requirement; technical conformity alone does not secure market access.

Which decisions these results support

Market access under radio equipment legislation
Verification of the antenna and RF front end design
SAR and RF exposure conformity
Verification of module integration and the scope of reassessment
Determining the worst case in multi-radio scenarios

Related Tests

Frequently Asked Questions About SAR — RED

Are European and US SAR results interchangeable?

No. The two regulations use different average mass (10 g and 1 g) and different limit values. Measurement and evaluation should be made according to the relevant method for each market.