Meaning
Safety thresholds established by regulatory bodies determine whether a portable wireless device must undergo laboratory testing for specific absorption rate. The sar exclusion threshold is a limit based on the output power of the transmitter and its proximity to the human body. Devices that operate below this calculated value are deemed safe by design and do not require the costly and time consuming process of phantom liquid testing.
Separation Distance
Separation parameters determine if a radio module qualifies for an exemption. When a device is used very close to the head or torso, the sar exclusion threshold decreases significantly because the intensity of the radio frequency field is higher at short ranges.
Power Determination
Frequency weighting accounts for the different ways energy is absorbed across the radio spectrum. The formula for the sar exclusion threshold incorporates the operating frequency to account for the depth at which electromagnetic energy penetrates human tissue.
Testing Waiver
Compliance paths are simplified when a manufacturer can demonstrate that a product stays within the safe power limits. Providing a data sheet that shows the peak conducted power is below the sar exclusion threshold allows the certification body to issue a grant without a full sar report. This documentation reduces the time required to bring new connected devices to the market.
