advertisement

Ask CNET Asia

Find Products

  • Brand
  • Price
  • Operating system
  • Phone type
  • Connectivity options
  • Touchscreen
  • Built-in digital camera?
  • Filter »

Buying Advice

Editors' Top 5s

CNET Features

 
 Print    Email     Bookmark     Share

How cell phone radiation works




SAR measurement setup (picture from Ericsson)
Measuring radio waves

Specific Absorption Rate (SAR) measures the RF energy absorbed by a certain amount of body tissue through using a particular mobile. It is usually expressed in units of watts per kilogram (W/kg).

There are currently two main standards for the measurement of SAR values, each with its own safety guidelines and set of adherents.

The standard adopted in Singapore and much of Europe was developed by the International Commission on Non-Ionizing Radiation Protection (ICNIRP), and has been endorsed by the World Health Organization (WHO). The SAR limit specified by the ICNIRP is 2.0W/kg, averaged over 10g of tissue.


Ericsson T68 up close (picture from Ericsson)
The Institute of Electrical and Electronics Engineers (IEEE) has also defined a standard, adopted by the US and other countries. It uses a limit of 1.6W/kg, averaged over 1g of tissue.

Either way, SAR tests are conducted by pouring simulated human tissue into a mould of a human head. The mobile phone under test is placed outside the mould and configured to operate on full power. A robot arm then inserts a probe into the "tissue" to find the area of the highest RF field, commonly known as the "hot spot". The probe measures a value, mathematically processed, whereupon the SAR value is derived.

To find the SAR values of the latest phones, you can check out the CNETAsia radiation chart.


What are radio waves? | Measuring SAR | Potential health hazards?

 

 
« Previous page | Potential health hazards? »

    Talkback
There are currently no comments for this story.
To post comments, you need to become a member. It's FREE.
advertisement