What Is SAR Testing?

1, What is SAR testing?

The full English name of SAR is Specific Absorption Rate, which is generally referred to as the electromagnetic wave absorption ratio or specific absorption rate in Chinese. It is the electromagnetic wave energy absorption ratio of wireless products such as mobile phones.

Generally speaking, SAR refers to the electromagnetic wave power absorbed or consumed per unit mass of human tissue per unit time, measured in W/kg, or equivalently, mW/g.

2, Which products require SAR testing?

Products that require SAR testing: Electronic products with transmitting antennas within 20cm of the human body and wireless transmission power greater than the SAR exemption power limit.

Common products include walkie talkies, tablets, laptops, USB dongles, POS machines, cordless phones, and more, in addition to mobile phones.

However, for some products that have wireless transmission capabilities but are used in a fixed location (belonging to fixed devices), the transmitting antenna is not close to the human body during use, so SAR testing is not required.For example, display screens and electronic display screens used for hanging walls in hospital wards.

3, How to conduct SAR testing?

The testing is a SAR measurement system composed of a human body model, measuring instruments, probe pairs, and a robotic arm. The system is placed in an environmentally controlled testing room, where the interior of the human body model is a liquid substance (simulating human tissue fluid), and the electromagnetic properties of the liquid are consistent with those of human tissue. The probe can move freely inside it for testing, and finally the SAR value is calculated through a formula.

4, What parameters/factors may affect the evaluation of SAR values?

The RF transmission power of wireless products, the position of the transmitting antenna, the temperature of the testing environment, the composition ratio of simulated human tissue fluid, the accuracy calibration parameters of the probe, and other factors may all affect the SAR test results.

What are the control regulations for SAR testing in various countries around the world?

Human exposure to radio frequency fields from hand-held and body-mounted wireless communication devices.Human models,instrumentation,and procedures Part 1:Procedure to determine the specific absorption rate(SAR)for hand-held devices used in close proximit YDT1644.

This standard provides clear descriptions and regulations for the human body model, measuring instruments, probes, human tissue fluid, robotic arms, and measurement calculation methods in the measurement system.

Limit requirement: In the network entry test, it is required that the SAR limit be taken as the average of 10g, with a limit of 2.0W/kg.

The SAR testing standards and limit requirements for other overseas countries (partially) can be found in the following table:

GRGTEST SAR testing capability

As a public service platform for industrial technology foundation of the Ministry of Industry and Information Technology, the Measurement and Testing Service Center of the China Communications Industry Association, and an accredited laboratory of the Federal Communications Commission (FCC) in the United States, GRGTEST has built a leading measurement and testing technology service capability in the wireless communication industry and established good cooperative relationships with numerous international authoritative certification agencies. It is committed to providing customers with one-stop testing and certification services, which can comprehensively help enterprises solve product access problems and enhance market competitiveness.