What is SAR Value in Smartphones?
Specific Absorption Rate (SAR) is a measure of the rate of Radio-Frequency (RF) Energy absorbed by the body from a cellphone. SAR testing provides a straightforward means for measuring the safety of cellphones and their compliance to International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. It is denoted in Watts per Kilogram (W/Kg), however different telecommunication regulatory bodies present in different countries have their own SAR levels for devices manufactured and sold.
SAR testing uses standardized models of the human head and body that are filled with liquids that simulate the RF absorption quality of a variety of human tissues. In order to determine compliance, each cell phone is tested while it is operating at its highest power level in all frequency bands and various positions on the stimulated human head and body.
Many people assume that using a cell phone with a lower reported SAR value necessarily decreases their exposure to RF emissions, or is somehow “safer” than using a cell phone with a high SAR value. While SAR values are an important tool in judging the maximum possible exposure to RF energy from a particular model of cell phone, a single SAR value does not provide sufficient information about the amount of RF exposure under typical usage conditions to reliably compare individual cell phone models. Moreover, cell phones constantly vary their power to operate at the minimum power necessary for communications; operation at maximum power occurs infrequently. Users concerned about RF exposure and its adverse effects are advised to hold the cellphone away from the head or the body and use a hands-free accessory.