Testing

SAR is Specific Absorption Rate, which is also called electromagnetic wave absorption rate or specific absorption rate in Chinese. It means the electromagnetic wave absorbed or consumed by a unit mass of human tissue in W/Kg or mw/g. The standard definition is the derivative of the unit electromagnetic energy (dW) relative to time in the unit material (dm) absorbed (dissipated) in the volume unit (dV) of a given material density (ρ)

SAR test is mainly refers to products with wireless transmission function being used closely to human body within distance of 20cm.

Classified by product type, it includes mobile phones, walkie-talkies, tablets, laptops, USB dongle, etc.

Classified by signal type, it includes GSM, WCDMA, CDMA, S-TDMA, BT, WIFI and 2.4G other products, 5G products, etc.

Classified by certification type, it includes CE, IC, Thailand, India, etc. Different countries have different specific requirements for SAR.

SAR limits and test frequency bands varied on different products and different countries. For details, please refer to table below:

Table 1-mobile phone

Table 2-push to talk

Table 3-PC

 However, not all products with a wireless transmitting antenna within 20cm of the human body need to have SAR test. Each country has another test method for products that meet the above conditions but with low power, which is called MPE evaluation. We call the power between these two testing standards as exemption limit. Exemption limit varies from country to country.

SAR Laboratory Environment Requirements:

The ambient temperature is 18-25℃, and the temperature change does not exceed ±2℃.

Moderately 30%-70%.

Avoid RF noise and ELF noise.

The influence of electrostatic effect on SAR test value.

The environmental noise (when the EUT is not transmitting a signal) is less than 3% of 0.4W/kg, which is 12 mw/kg.

SAR Testing Process and Certification Cycle

SAR test is mainly divided into three parts, tissue validation, system validation and DUT test. Normally, we will judge the test cycle, report cycle and certification cycle according to the different products and frequency bands. Usually, the more frequency bands, the longer the cycle.

 AGC has three sets SAR equipment for different standards, which are more efficient and faster in test cycle to meet emergent test for more customers. The frequency covers from 30MHz to 6GHz which almost covers all frequency bands on the market especially for 5G WIFI product and low-frequency products (136-174MHz). AGC can help customer products enter into foreign markets smoothly by solving test & certification issue.

Problem Sorting:

1.  What product needs SAR?

Mobile phones, walkie-talkies, telephones, tablet, wireless remote control products, WIFI products, Bluetooth products, 2.4G transmitters, 5G products, etc.

2. What are the SAR standards of CE and FCC?

CE: EN 50360; EN 62209-1; EN 62209; EN 62311; EN505662013

FCC: IEEE Std. 1528; 47CFR § 2.1093; IEEE/ANSI C95.1

Reference KDB procedure& TCBs files

3. How to determine whether a product needs SAR test?

If the separation distance between the user/or bystander and the device’s antenna/or radiating element is less than or equal to 20 cm, the SAR needs to be assessed. (Equipment operation lower than output power within the specified separation distance can be exempted)

FCC takes power as the exemption condition. The exemption limit (2.4G) 10dbm=10mw (average power), devices power bigger than 10dbm, SAR must be evaluated.

Reference file: KDB941225 D01v05;

CE takes power as the exemption condition. The exemption limit (2.4G) 13dbm=20mw (average power). For devices power bigger more than 13dbm, SAR must be evaluated;

Reference standard: EN50566:2013; EN62479.

IC takes power as the exemption condition, the exemption limit (2.4G) 6dbm=4mw (average power). Equipment power bigger than 6dbm, SAR must be evaluated;

Reference standard: IEEE 1528-2013

4. If SAR tested product has been updated, is it need to be re-tested?

If the antenna or motherboard of the product is changed, it will affect the SAR value and need to be re-tested. If only outer appearance, applicant and trademark are updated, no test is required buy applying a certificate according to customs’ requirement.