Calculating Portable Transmitter Specific Absorption Rate Evaluation Exemptions
Portable transmitter SAR evaluation exemptions depend on frequency, separation distance, and tune-up power to bypass costly physical chamber testing.
EN 62479
Meaning
European documentation governs the assessment of low power electronic equipment against human exposure limits to electromagnetic fields. This en 62479 standard specifies methods to verify that the power output or induced field strength of a device remains below the thresholds defined for health protection. It applies to equipment where the frequency range falls within the radio spectrum but the output power is sufficiently small that the device is incapable of exceeding safety limits without testing.
Compliance Methodology
Manufacturers use this harmonized framework to demonstrate conformity under the radio equipment directive. Documentation for en 62479 relies on simple power comparisons where the antenna gain and transmission power exist below the specified excitation limits. Products meeting these thresholds gain an exemption from the more rigorous specific absorption rate assessments.
Designers perform these calculations during the initial board layout phase to ensure the antenna placement allows for passive compliance.
Assessment Boundaries
Radiated energy calculations exclude complex near field effects when the device meets the low power criteria defined by the annexes. Any electronic item operating at frequencies exceeding the specified range or with power levels above the predefined milli-watt thresholds necessitates a full electromagnetic field exposure analysis instead of this simplified approach. Experts apply this standard exclusively to the specific transmitter circuit and antenna configuration as presented in the final product housing.
Certification Integration
Regulatory bodies require this assessment as a constituent part of the technical construction file for any wireless module. Each subassembly evaluation contributes to the final declaration of conformity by verifying that the combined radio output adheres to the safety requirements for end users. Verification of the power budget provides the final evidence for safety certification before the product enters the market.
Standalone Specific Absorption Rate Exclusion Thresholds for Portable Hosts
Standalone SAR exclusion allows portable wireless hosts to bypass laboratory phantom testing when time-averaged power falls below frequency-scaled distance thresholds.