SAR tests in the laboratory and verification of human exposure to radio frequencies

Wireless portable devices are now part of our daily habits and have almost become an extension of ourselves.
We frequently use our smartphone and carry it in our pocket, or we have a smartwatch on our wrist and we don't think that we are exposing parts of our body, in a prolonged manner, to electromagnetic fields generated by these objects which are always connected to some communication network.
Transmitting equipment that can be used in close contact with the body must undergo specific tests before being placed on the market: the evaluation of thehuman exposure to electromagnetic fields and the so-called SAR measurement.

What is SAR?

The HRH, acronym for Specific Absorption Rate it is defined as the amount of EM energy absorbed by the tissues of the human body per unit mass and is measured in W/Kg.
SAR tests, therefore, measure the percentage of electromagnetic energy absorbed by the human body when it is near a radio frequency magnetic field. The values thus obtained allow us to verify that the established limits of safe exposure to electromagnetic fields are respected.

Following the guidelines defined byInternational Committee for Non-Ionising Radiation Protection (ICNIRP), the European Union, the United States, Canada, Japan, Australia and others have approved harmonized standards that establish the maximum emission levels allowed to keep the absorption tolerance within certain safety thresholds.
By implementing these provisions, in the EU area the permitted SAR value is 2 W/Kg on 10 grams of tissue. The regulations of the United States and Canada impose more restrictive parameters, setting the limit at 1.6 W/Kg measured on 1 gram of tissue.

SAR tests in laboratories Sicom Testing

SAR measurement system Sicom Testing performs SAR measurement of electrical, electronic and telecommunications equipment that can be used in the vicinity of the body.
This laboratory is specially equipped to measure the rate of specific absorption of electromagnetic energy by human tissues when exposed to EMC fields.
The equipment it has Sicom Testing allow you to perform SAR measurements of small objects, such as portable phones, or large devices.
All measurements can be applied to different sensitive parts of the human body such as the head, abdomen or wrist.

The SAR measurement is carried out using a machine composed of a robotic arm, an electric field probe and particular tanks, the shape of which reproduces the model of the human head and body. Inside the tanks there is a special liquid that allows the characteristics of human tissue to be simulated.
The device on which the tests are carried out is then positioned underneath the tanks in order to simulate its use near the head or body. The measurement takes place through a complex test procedure, at the end of which the value obtained from the measurements is compared with the limits established by the reference regulations.

Sicom Testing: experience, competence and continuous innovation

Thermography of the head The lab Sicom Testing dedicated to this type of tests and measurements, and created thanks to the collaboration of the Area Science Park Research Institute and the Friuli Venezia Giulia Region, since 2006 it has been a unique reality in the area and established nationally for its recognized skills in the field of checks onhuman exposure.
In this compound Sicom Testing has developed proven experience in measurement, calculation and simulation techniques for SAR measurement, verifying the compliance of various devices with the different standards in force.

The continuous evolution of the reference standards is accompanied by constant updating work, focused on the skills and preparation of the staff as well as on the laboratory instrumentation.

Sicom Testing offers a complete risk assessment service human exposure to electromagnetic fields and the SAR measurement of your products.

To request further information on this topic, write to info@sicomtesting.com
or call +39 0481 778931.

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94 thoughts on “Prove SAR in laboratorio e verifica dell’esposizione umana alle radiofrequenze”

  1. Good evening, I wanted to ask you if you have tested or are aware of cell phone devices capable of mitigating exposure to electromagnetic clothing, thank you

    Reply
    • Good morning, we have tested several devices of this type. Some with shielding function, others with ferrites or magnets. We cannot disclose the results of the tests carried out. In all cases, the products put on the market are certified and therefore considered safe without further precautions. For prolonged use of the cell phone I recommend using a Bluetooth headset and leaving the cell phone on the table, the power of the Bluetooth headset is very low and the exposure is reduced.

      Reply
    • Good morning,
      The SAR values of a mobile phone depend on how it is built and on the maximum radio frequency transmission power, these parameters do not change over time as long as the mobile phone works correctly.
      Best regards
      Sicom Test

      Reply
  2. Hi, is the SAR test carried out with Wi-Fi, Bluetooth and GPS turned on or is a call simply simulated?

    Reply
    • Good morning,
      For all products with multiple radio transmitters for which it is necessary to perform the SAR, the various transmitters are tested individually one at a time, then the results are added as indicated by the standard, if the transmitters can operate simultaneously, to obtain the overall SAR value of the product.
      Best regards
      Sicom Test

      Reply
  3. in the case of virtual reality equipment used to watch augmented reality games, how is the SAR measurement performed?

    Reply
    • Good morning,
      For this type of equipment, the SAR is performed following the standard for products used close to the body, looking for the point of maximum emission on the frequencies of the radio transmitter. If the product does not contain radio transmitters it is not necessary to perform a SAR measurement.
      Best regards
      Sicom Test

      Reply
  4. Good morning. Regarding the SAR Values, I don't know if Xiaomi is a reliable brand. I would like to buy a Xiaomi 11 lite. Alternatively, a Samsung A52 or A72. Since I spend many hours on the phone, even without a headset, which one do you recommend?
    ABOVE ALL:
    Xiaomi has very interesting declared values. Ditto Samsung. But do both manufacturers detect Sar at the same distance in mm from the head and body?

    A thousand thanks!

    Reply
    • Good morning,
      the choice of device based on head and/or body SAR values depends greatly on the use made of the product. Regardless of the brand and manufacturer, smartphones must be tested according to the same measurement methods defined by the technical standards.
      Greetings from Sicom Testing

      Reply
  5. Hello, I would like to know if there is any reason why now several brands do not specify the SAR in the USA like Samsung (A52, A32, S20FE…), for most of their latest models it does not even appear on the official page It might be because it didn't pass the test in the US but in Europe it did? and that's why they can't put the results, because it's not marketed there.

    Thanks in advance

    Reply
    • Good morning,
      In some cases the devices are diversified at origin between America and Europe (for example the Samsung A52 sold in Europe is not necessarily the same Samsung A52 device sold in the United States), therefore for a device sold only in Europe no tests for the American market.
      Greetings Sicom Test

      Reply
      • Good evening. I purchased some freebuds 3: what is the SAR level of a type of wireless earphones like this compared to the emissions of a smartphone?
        In short, I know that my smartphone is around 0.5 head and 1 body. What Sar values am I dealing with with earphones? Thank you

        Reply
        • Good morning,
          To find out the SAR value of the earphones (if it is not declared) you need to test them; usually these types of earphones have very low transmission powers (a few mW), in this case the test is not performed because with such low powers the device cannot exceed the SAR limit values established by the regulations.
          Best regards
          Sicom Test

          Reply
  6. Good morning, I have further clarifications regarding the SAR values of mobile phones:
    – Why has the limit value of 4 W/kg relating to the limbs never been reported by the manufacturers in recent years but only those of the head and body?
    – Are the tests relating to the body carried out in the laboratory and the values found correlated to the limit values of the limbs? That is, if I keep the device in my pocket, does the body-based test refer to possible thigh absorption or should there be a separate analysis to evaluate this?

    Thanks in advance and good work!

    Reply
    • Good morning,
      -According to the EN 62209-2 standard the measurement method is the same for the trunk and limbs, generally referred to as the body, therefore a device that is within the limits of 2 W/Kg for the trunk is also compliant for the limbs which have a higher limit value.
      Greetings Sicom Test

      Reply
  7. One person wrote to us:
    1) In one of the answers you explicitly refer to Bluetooth earphones when it comes to making long phone calls. Are normal (wired) earphones not recommended? Do they make the body perceive a greater electromagnetic field value than Bluetooth earphones?

    2) The second question concerns smartphones that also implement 5G technology. Is the SAR value in this case influenced by the presence of the 5G antenna? (which from what I know is a significantly different technology than 4G, so it should require a different hardware architecture). In other words, does the possible presence of the antenna to receive/transmit data in 5G increase the SAR value? If so, significantly or negligibly compared to an exclusively 4G smartphone?

    Thank you again for your professionalism and friendliness.

    Our answer:
    1) Wired earphones have no influence on the SAR values of the device. The advantage of using earphones is due to the fact that during the phone call the cell phone can be held away from the body.

    2)The SAR value, as well as on the communication technology, also depends on the device, furthermore 4G or 5G communications are alternatives and do not take place at the same time, therefore 5G does not increase the SAR of 4G; the SAR values of a device while transmitting in 5G are measured separately from the SAR values of the same device while transmitting in 4G, it is not possible to know a priori in which mode the SAR will be higher.

    Reply
  8. Hi, I have some clarification questions regarding the SAR measurement method for mobile phones:
    – When the defined measurements are carried out in worst conditions, to define the SAR for each frequency in which it works, a single test is carried out with the telephone at maximum power working at the same time in all available frequencies or more measurements are made, separately for each frequency, and then establish the maximum value at the end?
    – In what time interval are SAR measurements taken to arrive at the final value?
    – If manufacturers only declare the SAR value without further specification, they usually refer to the maximum value of which frequency?

    Thanks in advance for your reply and good work!

    Reply
    • Good morning,
      -SAR measurements are performed on each frequency band on which the device can work, if frequencies of multiple bands can be used simultaneously the SAR values are added according to the methods indicated by the standard.
      -All SAR values are obtained as an average over a 6 minute period (for Europe).
      -The declared SAR value is the highest of all those measured.
      Best regards
      Sicom Test

      Reply
  9. Hi, my question is… Why do some devices have SAR in Europe but SAR is hidden in USA? As in the case of the Samsung a40

    Thank you

    Reply
    • Good morning.
      If you are referring to the SAR values reported in the manual, generally for models sold in the European market only the SAR values with European limits are reported, while for models marketed in the United States the values reported are those relating to the US limits.
      On the manufacturer's website there should be both values.
      Greetings from Sicom Testing

      Reply
  10. Dear Sicom, I would like to know if a wall inside a house, even if relatively thin (8cm), reduces the transmission of waves coming from an old generation mobile phone. Thanks Good work

    Reply
    • Good morning.
      A wall can be an obstacle to the propagation of radio waves, depending on the frequency band in which the mobile phone is operating and the material of the wall.
      However, if the concern is human exposure, moving 8cm or more away from the mobile phone leads to a significant reduction.
      Greetings from Sicom Testing

      Reply
  11. Dear Sicom, congratulations on the competence and importance of your work. Why don't all companies express the SAR value on their cell phone packages? We often read that these devices comply with European regulations without however reporting the SAR value figures. Finally, I would like to know if a cell phone turned on stand-by can transmit its waves through an 8 cm perforated wall. I ask this because I once left an old generation mobile phone turned on for an entire night behind a wall like the one indicated corresponding to the head of someone sleeping in the other room, whose total distance between the head and the mobile phone was 25 cm including the 8 cm perforated wall. Many thanks for your attention and response. I greet you distinctly.

    Reply
    • Good morning.
      When the information is not available on the packaging it can probably be found on the manufacturer's website. In reality, the important aspect is that the product is within the limits set by the regulations and considered safe.

      The phone in standby transmits and receives information. The amount is very low if the data connection is not enabled. However, it increases with data connection and active applications on smartphones.

      Human exposure when using a mobile phone varies greatly between the case in which the product is in contact with the person and when it is a few centimeters away. In this case I believe that the distance of 25 cm should be considered sufficiently safe.

      Greetings from Sicom Testing

      Reply
  12. Hey!
    Let's say we have two cell phones.
    -Mobile A has these sar values: head 0.558 W/Kg, body 0.986 W/Kg
    -Mobile B has these sar values: head 0.191 W/Kg, body 1.034 W/Kg
    1) The radiation transmitted via hands-free wire is related to which of these values? Will it transmit more radiation to the head in case of smartphone A or B?
    2) Although cell B has a slightly higher body sar value, at the same time it has a significantly lower head sar value than cell A. What is the cause of this difference? Just the antenna placement?
    3) Is there a maximum distance between body / head and device where these values are applicable, or are they to be considered only when we are in contact with the device?
    3b) If the answer above is that sar values are only applicable when in contact with the device, can we assume that the least harmful device is the one with the generally lowest sar value (hence weaker electromagnetic field)? In our example this would be mobile A because its highest sar value (value sar body) is lower than the highest sar value of mobile B (again value sar body). My idea behind this is that the highest possible value will create a potentially stronger electromagnetic field. So if the sar values are only applicable when we touch the phone, I was wondering what value I should take into consideration when speaking on speakerphone.
    I don't have much knowledge of physics, please correct me if my assumption is wrong.

    Thanks in advance!

    Reply
    • Good morning.
      1) The radiation transmitted via hands-free wire is not related to any of these values.
      2) It can be the location and type of antenna.
      3) Normally the values are measured by contact. The measurements are repeated in different positions following the indications of the standards and the value reported is the worst among those obtained.
      3B) By moving the mobile phone away from the body, including the head and hand, even by a few centimeters, the absorption of radiation is rapidly reduced.
      Greetings from Sicom Testing

      Reply
  13. Good evening and thank you for your answers,
    I would like to know when obviously different European and US SAR values are found online, are they tested under the same band conditions? do they use the same frequency? another question, at this point if I have a lower SAR value in the USA and higher in Europe, shouldn't it be the opposite?
    Thank you

    Reply
    • Good morning.
      The frequency bands used in Europe and the USA are different and SAR measurements are carried out in the bands relevant to the geographical area concerned. Furthermore, there are some technical details in the execution of the tests which in some cases can lead to differences. For all these reasons, the same SAR values are not found for Europe and the USA. However, I confirm that all other factors being equal, the fact of averaging the measurement on 1 g of tissue (USA) instead of 10 g of tissue (Europe) should capture a higher part of the spatial peak of absorption, therefore giving a size a little higher.
      Greetings from Sicom Testing

      Reply
  14. One person wrote to us:

    “Reading the article the following questions arose:

    1) In some sites that report SAR values, a distinction is made between SAR head and SAR body and in some cases these values differ quite a lot (for example the Samsung Note 8 has a head SAR of 0.17 W/kg while the SAR body is significantly higher (1.29 W/kg). Why is there this huge difference in some smartphones while in others the values are the same (if not even reversed)?

    2) Is it better to favor smartphones with head and body SAR values that are equivalent or is it better to look more at one of the 2 data (head rather than body)?

    3) Is the SAR value reported by the manufacturer measured during the maximum effort of the equipment? (like a call?) Or is it a value measured while searching for the repeater to establish the connection with the cell?

    4) Do smartphones with dual SIM stand by technology emit the same amount of radiation as a single SIM? And if they are used with just one SIM, do things improve?
    John"

    Our answer:

    The head SAR value depends on the positioning of the antenna with respect to the head, if it is close to the microphone and the smartphone is large, the antenna moves away and the SAR value decreases.

    The SAR body is measured on all sides of the product and the worst values are reported, so the position of the antenna and the size of the smartphone have less impact.
    It is important to be aware that these products, even when carried in your pocket, expose us to electromagnetic fields when they exchange data; and this almost always happens unless the data has been disabled.

    The SAR body indicates the exposure to which one is subjected in this case, while the SAR head indicates the exposure to which one is subjected during a telephone conversation holding the phone close to the ear. So the most interesting value for each of us depends on the use we make of the product.

    Keeping your smartphone in your bag instead of in your pocket actually makes a lot of difference.

    If you make long phone calls, it is better to use the speakerphone or a Bluetooth headset by placing the phone on the desk.

    Compared to these measures, the SAR value of the product is a less decisive factor, but it is still a factor.

    Regulatory bodies wanted SAR values to be public to encourage designers to reduce them as much as possible.

    However, let's not forget that all the products that are regularly on the market are within limits considered safe, therefore if used appropriately they are not to be considered harmful. It is naturally important that all products are correctly tested before being placed on the market.

    Greetings from Sicom Testing

    Reply
  15. Hi, my question is as follows: If we have a base station on a rooftop that emits at around 40 dBm (10 watts), I would like to know if I am meeting the SAR limits of personnel inside the building.

    Thank you very much.

    a greeting

    Reply
    • Good morning.
      The human exposure assessment for a product intended to be permanently installed is done in a different way than SAR. Starting from the technical characteristics of the product and measurements, the minimum distance at which people must stand during use is calculated.
      Greetings from Sicom Testing

      Reply

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