SAR Testing Solutions: SAR and HAC Testing


SAR Testing Solutions: SAR and HAC Testing

With the development of information technology, the public is increasingly concerned about the impact of electromagnetic radiation from wireless communication terminals on human health, because mobile phones and tablets have become an indispensable part of our daily life, whether it is to keep in touch with loved ones, keep in touch with work, or just enjoy entertainment on the road, these devices have truly revolutionized our way of life. So it's important to make sure these devices are user-friendly and safe to use. This is where the BTF testing lab and its expertise in SAR, RF, T-Coil and Volume control tests come into play.

SAR (specific absorption rate) testing is mainly for portable devices, such as mobile phones, tablets, watches and laptops, etc. SAR testing is the meaning of the electromagnetic power absorbed or consumed per unit mass of human cells. Our BTF testing lab specializes in SAR testing and is fully equipped to meet the requirements of the test environment, as well as to ensure that the equipment complies with the safety limits set by the regulatory authorities. By conducting SAR testing, manufacturers can guarantee that their products do not pose any health risks to users.

Body Position

SAR Value (W/Kg)

General Population/

Uncontrolled Exposure


Controlled Exposure

Whole-Body SAR

(averaged over the entire body)



Partial-Body SAR

(averaged over any 1 gram of tissue)



SAR for hands, wrists, feet and ankles

(averaged over any 10 grams of tissue)




General Population/Uncontrolled Exposure: Locations where there is the exposure of individuals who have no knowledge or control of their exposure. General population/uncontrolled exposure limits are applicable to situations in which the general public may be exposed or in which persons who are exposed as a consequence of their employment may not be made fully aware of the potential for exposure or cannot exercise control over their exposure. Members of the general public would come under this category when exposure is not employment- related; for example, in the case of a wireless transmitter that exposes persons in its vicinity.


Occupational/Controlled Exposure: Locations where there is exposure that may be incurred by persons who are aware of the potential for exposure, In general, occupational/controlled exposure limits are applicable to situations in which persons are exposed as a consequence of their employment, who have been made fully aware of the potential for exposure and can exercise control over their exposure. This exposure category is also applicable when the exposure is of a transient nature due to incidental passage through a location where the exposure levels may be higher than the general population/uncontrolled limits, but the exposed person is fully aware of the potential for exposure and can exercise control over his or her exposure by leaving the area or by some other appropriate means.

HAC testing Evaluation limits

Hearing Aid Compatibility (HAC) This is a certification that digital mobile phones will not interfere with nearby hearing AIDS before communication, that is, to test the electromagnetic compatibility of mobile phones and hearing AIDS, which is divided into three parts: RF, T-coil and Volume control test. We need to test and evaluate three values, the first value is the magnetic field density of the intentional signal (system signal) at the center frequency of the audio frequency band, the second value is the frequency response of the intentional signal over the entire audio frequency band, and the third value is the difference between the magnetic field strength of the intentional signal (system signal) and the unintentional signal (interference signal). The reference standard of the HAC is ANSI C63.19 (the National Standard Method for Measuring the compatibility of Wireless communication equipment and hearing AIDS in the United States), according to which the user defines the compatibility of a certain type of hearing aid and mobile phone through the anti-interference level of the hearing aid and the corresponding mobile phone signal emission level.


SAR test chart

The entire test process is performed by first measuring the magnetic field strength in the audio frequency band useful for the hearing aid T-coil. The second step measures the magnetic field component of the wireless signal to determine the effect of intentional signals in the audio frequency band, such as the display of the wireless communication device and the battery current path. The HAC test requires that the limit of the tested mobile phone is M3 (the test result is divided into M1~M4). In addition to the HAC, the T-coil (audio test) must also require a limit in the T3 (test results are divided into T1 to T4) range.

Emission categories

<960MHz Limits for E-field emissions

>960MHz Limits for E-field emissions


50 to 55 dB (V/m)

40 to 45 dB (V/m)


45 to 50 dB (V/m)

35 to 40 dB (V/m)


40 to 45 dB (V/m)

30 to 35 dB (V/m)


< 40 dB (V/m)

< 30 dB (V/m)

RFWD RF audio Interference level categories in logarithmic units


Telephone parameters WD signal quality [(signal + noise) – to – noise ratio in decibels]

Category T1

0 dB to 10 dB

Category T2

10 dB to 20 dB

Category T3

20 dB to 30 dB

Category T4

> 30 dB


RF and T-coil test chart

By combining the expertise of our BTF testing lab with advances in mobile phone and tablet technology, manufacturers can produce devices that not only provide a seamless user experience but also meet all safety standards. The collaboration between the BTF testing lab and the manufacturer ensures that the device is tested for SAR, RF, T-Coil and volume control compliance.


HAC testing

Post time: May-30-2024