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SAR tests in the laboratory and human exposure occurs at radio frequency

SAR tests in the laboratory and human exposure occurs at radio frequency

The wireless handheld devices are now part of our daily habits and have almost become an extension of ourselves.
Frequently we use the smartphone and carry it in his pocket, or we the smartwatch the wrist and do not think that we are exposing our body parts, and hold, to electromagnetic fields generated by these objects that are always connected to some communication network.
The broadcasting apparatus usable in close contact with the body must be subjected to specific tests before being put on the market: the assessment of’human exposure to electromagnetic fields and the so-called measure of SAR.

What is the SAR?

The SAR, stands for Specific Absorption Rate It is defined as the amount of EM energy absorbed by human body tissues on unit mass and is measured in W / Kg.
The SAR testing, then, measure the percentage of electromagnetic energy absorbed by the human body when this is located in the vicinity of a magnetic field radiofrequency. The values ​​thus obtained make it possible to verify that they comply with the limits of safe exposure to electromagnetic fields.

Following the guidelines defined by 'International Committee for Non-Ionising Radiation Protection (ICNIRP), the European Union, the United States, it Canada, Japan, Australia and other, approved standards, which determine the maximum emission levels permitted to contain within certain safety thresholds tolerance absorption.
By incorporating these provisions, in the allowable SAR value of the EU is 2 W / Kg su 10 grams of tissue. The US and Canada regulations impose stricter parameters, by fixing the limit at 1,6 W / Kg misurati su 1 gram of tissue.

The SAR testing in laboratories Sicom Testing

SAR measurement system Sicom Testing It performs the SAR measurement of electrical equipment, electronic and telecommunication can be used in the vicinity of the body.
This workshop is specially equipped for measuring the specific absorption rate of electromagnetic energy by the human tissue when exposed to EMC fields.
The equipment available to Sicom Testing allow you to perform SAR measurements of small objects, such as portable phones, or larger devices.
All measurements can be applied to various sensitive parts of the human body such as the head, the abdomen or wrist.

The SAR measurement is carried out using a machine made by a robotic arm, by an electric field probe and from special tanks, the shape of which reproduces the model and of the head of the human body. Inside the tanks it is contained a special liquid that allows to simulate the characteristics of human tissue.
The device on which the tests are carried out is then positioned below the tanks in order to simulate its use near the head or body. The measurement is carried out by means of a complex test procedure, at the end of which the value obtained by the measures is compared with the limits laid down by the regulations rifermento.

Sicom Testing: experience, expertise and continuous innovation

Thermography of the head The lab Sicom Testing dedicated to this type of test and measurement, and realized thanks to the collaboration of the Research Area Science Park and Friuli Venezia Giulia, from the 2006 It is unique in the area and established itself nationally recognized for its expertise in the field of checks on’human exposure.
In this compound Sicom Testing He has developed proven expertise in measuring techniques, calculation and simulation for measure of SAR, verifying the conformity of various devices to the various existing standards.

The continuous evolution of the reference standard is accompanied by a constant work of renovation, focused on skills and training of personnel as well as on laboratory instrumentation.

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

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

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90 comments on "SAR tests in the laboratory and verification of human exposure to radio frequencies”

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

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

  1. good morning. As for the SAR values, I don't know if Xiaomi is a reliable brand. I would like to buy a Xiaomi 11 quarrel. Alternatively, a Samsung A52 or A72. Since I spend many hours on the phone, even without a headset, which one do you recommend?
    MOSTLY:
    Xiaomi has very interesting declared values. I'm going Samsung. But both manufacturers detect the SAR at the same distance in mm from the head and body?

    Thanks so much!

    • good morning,
      the choice of the device based on head and / or body SAR values ​​greatly depends on the use 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

  2. Ciao, I would like to know if there is any reason why now several brands do not specify SAR in the United States such as Samsung (A52, A32, S20FE …), for most of their latest models it does not even appear on the official page It could be because it did not pass the test in the US but in Europe it did? and that is why they cannot put the results, because it is not marketed there.

    Thanks in advance

    • Good morning,
      In some cases the devices are originally diversified 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, tests for the American market are not performed.
      Greetings Sicom Test

      • good evening. I bought some freebuds 3: what is the Sar level of a kind of wireless earphones like this compared to the emissions of a smartphone?
        in conclusion, i know my smartphone is around 0,5 head and 1 leotard. With the earphones with what Sar values ​​I am dealing with? Thank you

        • good morning,
          To know the SAR value of the earphones (if it is not declared) you have to test them; usually these types of earphones have very low transmitting powers (some 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 legislation.
          Kind regards
          Sicom Test

  3. good morning, I would have other clarifications regarding the SAR values ​​of mobile phones:
    – How come in recent years the limit value of 4 W / kg relative to the limbs but only those of the head and body?
    – The tests relating to the body carried out in the laboratory and the values ​​found are correlated to the limb limit values? Or, if I keep the device in my pocket, the test referred to the body refers to the possible absorption of the thigh or there should be a separate analysis to evaluate it?

    Thanks in advance and good luck with your work!

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

  4. One person wrote to us:
    1) In one of the answers you explicitly refer to bluetooth headsets when it comes to making long phone calls. Normal earphones (with the thread) are not recommended? They make the body perceive a greater value of electromagnetic field than bluetooth headsets?

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

    I thank you again for your professionalism and friendliness.

    Our answer:
    1) Corded earphones have no influence on the SAR values ​​of the device. The advantage of using earphones is that the mobile phone can be kept away from the body during the phone call.

    2)The SAR value, in addition to the communication technology, it also depends on the device, moreover, communications in 4G or 5G are alternative and do not take place simultaneously, 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 in advance in which mode the SAR will be higher.

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

    Thanks in advance for your reply and good luck!

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

    • good morning.
      If it refers to the SAR values ​​shown in the manual, basically, for the models sold on the European market, only the SAR values ​​with European limits are reported, while for the models sold in the United States the values ​​shown are those relating to the USA limits.
      On the manufacturer's website there should be both values.
      Greetings from Sicom Testing

  6. Dear Sicom, I would like to know if a wall inside a house, albeit relatively thin (8Cm) reduces the transmission of waves coming from an older generation cell phone. Thanks Good job

    • good morning.
      A wall can be an obstacle to the propagation of radio waves, it depends on the frequency band in which the cell phone is operating and the wall material.
      If, on the other hand, the concern is human exposure, the fact of getting away from 8 cm or more from the mobile phone leads to a significant reduction.
      Greetings from Sicom Testing

  7. Dear Sicom, congratulations for the competence and importance of your work. Why not all companies express the SAR value in their cell phone packages? We often read that these devices comply with European regulations but without reporting the SAR figures. Finally, I would like to know if a cell phone on standby can transmit its waves through a perforated wall 8 Cm. I ask because once I left an old generation mobile phone on for a whole night behind a wall like the one indicated at the head of someone who slept in the other room, whose total distance between the head and the cell phone was 25 cm including the perforated wall from 8 Cm. Many thanks for your attention and response. I greet you distinctly.

    • 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 idle telephone transmits and receives information. The amount is very low if the data connection is not enabled. Instead, it increases with data connection and applications active on smartphones.

      Human exposure in the use of a mobile phone changes a lot 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 the distance of 25 cm is to be considered sufficiently safe.

      Greetings from Sicom Testing

  8. Hey!
    Let's say we have two cell phones.
    -Cell phone A has these sar values: head 0,558 W / Kg, body 0,986 W / Kg
    -Cell phone B has these sar values: head 0.191 W / Kg, body 1.034 W / Kg
    1) The radiation transmitted via speakerphone wire in relation to which of these values ​​it is? It will transmit more radiation to the head in case of smartphone A or B?
    2) Although cellphone B has a slightly higher body sar value, at the same time it has a significantly lower sar value of the head than cellphone A. What is the cause of this difference? Only the positioning of the antenna?
    3) There is a maximum distance between the body / head and device where these values ​​are applicable, or they are to be considered only when we are in contact with the device?
    3b) If the answer above is that the sar values ​​are only applicable when in contact with the device, we can assume that the least harmful device is the one with the generally lower value (therefore weaker electromagnetic field)? In our example this would be mobile A because its value will be higher (value will be body) is less than the higher sar value B of the mobile phone (of new value will be body). My idea behind this is that the highest sar value possible is capable of creating a potentially stronger electromagnetic field. So, if the sar values ​​are only applicable when we touch the phone, I was wondering what value should I take into consideration when speaking on speakerphone.
    I don't have much knowledge of physics, please correct me if my guess is wrong.

    Thanks in advance!

    • good morning.
      1) The radiation transmitted through the 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 in contact. The measurements are repeated in different positions following the indications of the standards and the reported value is the worst of those obtained.
      3B) Removing the cell phone from the body, including head and hand, even a few centimeters, the absorption of radiation is rapidly reduced.
      Greetings from Sicom Testing

  9. Good evening and thanks for the answers you provide,
    I would like to know when the European and US SAR values ​​are obviously different on the net, they are tested under the same band conditions? meaning they use the same frequency? another question, at this point if I have a lower SAR value than USA and higher Europe, it shouldn't be the other way around?
    thanks

    • good morning.
      The frequency bands used in Europe and the US are different and SAR measurements are carried out in the bands relevant to the geographic area concerned. In addition, there are some technical details in the execution of the tests which in some cases can lead to differences. For all of 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 measure on 1 g of tissue (USA) instead of 10 g of tissue (Europe) it should capture a higher part of the spatial absorption peak, so give it a little fit’ higher.
      Greetings from Sicom Testing

  10. One person wrote to us:

    “Reading the article, the following questions arose:

    1) In some sites that report the SAR values, a distinction is made between SAR head and SAR body and in some cases these values ​​also differ significantly (for example the Samsung Note 8 has a SAR head of 0,17 W / kg while the SAR body is significantly higher 1,29 W / kg). Why is there this abysmal difference in some smartphones while in others the values ​​are the same (if they don't even reverse)?

    2) It's’ better to privilege smartphones with head and body SAR values ​​that are equivalent or it is better to look more at one of the 2 data (head rather than body)?

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

    4) Smartphones with dual sim stand by technology emit the same amount of radiation as a single sim? And if they are used with only one sim, things get better?
    John”

    Our answer:

    The SAR head value depends on the positioning of the antenna with respect to the head, if it is near 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, therefore the position of the antenna and the size of the smartphone matter less.
    It's’ It is important to be aware that these products, even when carried in your pocket, expose us to electromagnetic fields when exchanging 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 is the one to which you are subjected during a telephone conversation holding the phone close to your 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 makes a lot of difference.

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

    Compared to these precautions, the product's SAR value is a less determining factor, but it's still a factor.

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

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

    Greetings from Sicom Testing

  11. Salve, my question is the following: if we have a base station on a roof that emits at approx 40 dBm (10 watt), I would like to know if I am respecting the SAR limits of the staff inside the building.

    Thank you very much.

    a greeting

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

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Sicom Testing will be happy to answer you.