Understanding Specific Absorption Ration ( Sar) Levels and Mobile Phone Radiation Part 2
Cell Tower Protection
A robot which consists of a mechanical arm and a special probe is then used to derive the actual SAR measurements. The measurements are carried out by establishing a reference point in the phantom and then scanning a specified area in and around the phantom while the phone is operating at its maximum certified power level.
The scan inside the phantom and within the liquid measures the electric field strength within the head.
This data is then used to calculate the SAR – resulting in a three dimension map indicating the maximum SAR value recorded during the test.
The standard specifies two positions for testing, reflecting that consumers hold their phone in different positions while talking. Therefore once the test has been completed in the first position, the phone is adjusted and the tests carried out again.
The process outlined above is then replicated again with the antenna in and out (if applicable); and for the high, medium and low point of each frequency band that the phone is designed to operate on. Therefore for a dual or tri-band phone, the complete testing protocol including accessories can take up to two weeks for each phone.
The end result of this process is the determination of the maximum SAR value for that particular phone and this value is then compared to the exposure limits permitted under the various compliance standards in operation. Once completed, the test results will be used as the basis for the published SAR values that are provided to consumers and to regulators alike.
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