Specific absorption rate (SAR) is a measure of the rate at which energy is absorbed by the human body when exposed to a radio frequency (RF) electromagnetic field; although,it can also refer to absorption of other forms of energy by tissue, including ultrasound.[1] It is defined as the power absorbed per mass of tissue and has units of watts per kilogram (W/kg).[2] SAR is usually averaged either over the whole body, or over a small sample volume (typically 1 g or 10 g of tissue). The value cited is then the maximum level measured in the body part studied over the stated volume or mass.

Mobile Phone SAR Testing

Testing System Includes:

  • United States: the FCC requires that phones sold have a SAR level at or below 1.6 watts per kilogram (W/kg) taken over the volume containing a mass of 1 gram of tissue that is absorbing the most signal.
  • European Union: CENELEC specify SAR limits within the EU, following IEC standards. For mobile phones, and other such hand-held devices, the SAR limit is 2 W/ kg averaged over the 10 g of tissue absorbing the most signal (IEC 62209-1).
  • India: switched from the EU limits to the US limits for mobile handsets in 2012.Unlike the US, India will not rely solely on SAR measurements provided by manufacturers; random compliance tests are done by a government-run Telecommunication Engineering Center (TEC) SAR Laboratory on handsets and 10% of towers. All handsets must have a hands free mode.
  • MRI Scanner SAR Testing: For Magnetic Resonance Imaging the limits (described in IEC 60601-2-33) are slightly more complicated