Specific absorption rate (SAR) is a measure which explains how much radio frequency energy is absorbed by the user’s or bystander’s body or head. This article will focus specifically on mobile devices’ SAR value.
RF exposure evaluation is required before a device, with a radio transmitter, is permitted to go on the market for sale. The RF exposure evaluation for devices that are used closer than 20 centimetres to a human or animal body is done by testing the SAR value. SAR is measured at maximum power levels under laboratory conditions. The measurement of SAR is watts per kilogram (W/kg) and it measures the amount of radio frequency radiation absorbed by the body when using a wireless device. To test the device for SAR compliance, it is placed in various common talk positions next to the head and body. After that, a series of measurements of the electric field is made. The results explain how much radio frequency energy is absorbed by the body or head.
Throughout many years there has been several market SAR surveillance tests conducted. These surveillances have discovered that a part of smart phones in the market exceeded the allowed SAR value.
The French National Frequency Agency (ANFR) conducted SAR surveillance tests for phones already being sold on the market. The finding are described in Finnish newspaper in an article published 30th of November 2018. ANFR tested in total of 51 phone models. In the EU, the maximum SAR value is 2 W/kg. According to the tests most of the tested phones were below the limit.
Nevertheless, several smartphone models had SAR values that were over the regulation limits. Some of these phone models are also sold in Finland. These models received software updates to lower the radiation to the permissible level allowing the products to remain on the Finnish market. Not all manufacturers were able to take such actions and, thus had remove their devices from the market until their violation is resolved.
Market surveillance has an important role ensuring that only qualified and regulatory approved products are on the market. The market surveillance for mobile phones is done by constant retests of SAR values allowing only the devices that are qualified to be on the market.
Verkotan is always happy to provide more detailed information and make a proposal how we can verify the performance of your wireless device in the global environment.
If you have any questions or need assistance, contact us. We are happy to help you!