Simultaneous Transmit SAR Evaluation Thresholds in Portable Radio Systems
Simultaneous SAR evaluations require summing standalone SAR or estimated values to prove combined exposure remains below regulatory limits.
10-G SAR
Meaning
Localized thermal evaluation standards measure the rate of RF energy absorption over a specific mass of human tissue to verify user safety. Regulatory bodies in Europe and other international regions use 10-g SAR to define exposure limits for mobile devices. This metric averages the absorbed power over a ten-gram cube of continuous tissue, representing a wider spatial area than some alternative standards.
The boundary for this evaluation extends to any wearable or hand-held wireless device that operates in close proximity to the human body.
Tissue Mass
A larger averaging mass reduces the sensitivity of the measurement to highly localized peak values. This ten-gram volume smoothing typically results in lower reported values compared to smaller mass distributions.
Compliance Test
Laboratory assessments use anatomical models filled with tissue-equivalent liquid to record the physical energy deposition. For hand-held devices, the limit of a 10-g SAR calculation is 2.0 watts per kilogram for general public exposure. Automated positioning systems move an electric field sensor through the liquid to capture the three-dimensional power profile.
These measurements must be completed across all operating bands to secure market entry.
Module Evaluation
System integrators select wireless transmitters and plan antenna layouts to ensure the fully assembled product remains within safe margins. Transmit power limits are programmed into the firmware during the production phase to prevent unexpected peaks. Testing the finished enclosure rather than the standalone transmitter ensures that internal shielding and reflections do not create localized fields.
Complete test reports with these measurements are filed with designated conformity assessment bodies before product launch.