Specific Absorption Rate
Specific Absorption Rate (SAR) is the measure of the amount of higher frequency Radio Frequency (RF) Electromagnetic Field (EMF) absorbed by the human body when using an electronic device. This rate is measured as the power absorbed within a defined area of body tissue in a standard measurement of watts per kilogram (W/kg). The Specific Absorption Rate (SAR) can be an average measure over the entire body, or a small sample amount. What you get is the greatest level measured in a defined area of the body.
Specific Absorption Rate (SAR) measures exposure within the frequency range of 100 kHz and 10 GHz which includes electronic devices such as laptops, WiFi routers and cell phones. The value is highly dependent upon the body parts being tested, energy levels and the proximity to the radiating source. The Specific Absorption Rate (SAR) value is established by selecting areas of the body to be tested, finding the highest absorption rate while exposing that area closest to the radiating source.
There are guidelines for Specific Absorption Rate (SAR) established by national and international organizations. For example, the following are Specific Absorption Rate (SAR) requirements for cell phones:
The Federal Communication Commission (FCC), in the US, requires that phones sold have a SAR level at or below 1.6 watts per kilogram (W/kg) taken over a volume containing a mass of 1 gram of tissue. In Europe, there is the European Union. They specify Specific Absorption Rate (SAR) limits within the EU for mobile phones and other such hand-held devices, to be less than or equal to 2 W/kg averaged over 10g of tissue.