What is SAR?
Specific absorption rate (SAR) is a parameter to measure the rate at which energy is absorbed by the human body when exposed to a radio frequency (RF) electromagnetic field. It is defined as the power absorbed per mass of tissue and has units of watts per kilogram (W/kg).
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.
SAR limits
| United States (USA) |
1.6 W/kg on 1g of tissue |
| European Union (EU) |
2W/kg on 10g of tissue |
| India |
Switched to US measurements. 1.6W/kg on 1 g of tissue |
Why to be scared of SAR?
The SAR value used for approval does not account for the multitude of measurements taken during the testing. Moreover, cell phones constantly vary their power to operate at the minimum power necessary for communications.
Although the SAR is determined at the highest certified power level in laboratory conditions, the actual SAR level of the phone while operating can be well below this value. This is because the phone is designed to use the minimum power required to reach the network. Therefore, the closer you are to a base station, the more likely it is that the actual SAR level will be lower.
Cell phone A might have one measurement that was higher than any single measurement for cell phone B. Cell phone A would, therefore, have a higher reported SAR value than cell phone B, even if cell phone B has higher measurements than A in most other locations and/or usage configurations. In such a case, a user generally would receive more RF energy overall from cell phone B.
Cell phone A might communicate more efficiently than cell phone B, so that it operates at lower power than cell phone B would under comparable conditions. Consequently, a user would receive more RF energy overall from cell phone B.
The highest value from cell phone A might come from a position which the user seldom or never employs to hold a phone, whereas that user might usually hold a phone in the position that resulted in the highest value for cell phone B. Therefore, the user would receive the highest RF exposure that cell phone B delivers but would not receive the highest RF exposure that cell phone A delivers.
Bottomline
Though SAR limits enforced by regulatory authorities, keeps manufacturers in check to keep values within permissible limits. One cannot say that a particular cell phone will emit less radiations than the other just because of low SAR values. Its better if we get the information about the Max SAR value of the phone was observed under which circumstances.
References:
https://en.wikipedia.org/wiki/Specific_absorption_rate
https://www.fcc.gov/consumers/guides/specific-absorption-rate-sar-cell-phones-what-it-means-you
http://www.samsung.com/sar/sarMain?site_cd=&prd_mdl_name=note3&selNatCd=IN&languageCode=EN
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