Calculating Total Exposure Ratios for Co Located Transmitters in Handheld Equipment
Multi-radio handheld exposure compliance requires summing normalized SAR values across concurrent transmitters to verify the total exposure ratio stays below unity.
Peak Location Distance Ratio
Meaning
Spatial measurement evaluates the separation between localized maximums in a distributed physical field. The peak location distance ratio quantifies the proximity of peak Specific Absorption Rate locations during simultaneous transmission testing. This metric determines whether the electromagnetic fields from multiple antennas overlap or act independently.
The evaluation applies primarily to multi-transmitter devices where the distance between the primary and secondary peaks affects the aggregate safety margin, establishing a threshold where the combined radiation pattern must be evaluated as a single composite source rather than two isolated emissions.
Distance Measurement
Peak spacing provides the mathematical foundation for calculating cumulative energy distribution. In simultaneous SAR analysis, the peak location distance ratio compares the spatial coordinates of the highest absorbed power from each antenna. This calculation requires precise probe positioning.
Transmission Evaluation
Radio co-location necessitates rigorous assessment to ensure that adjacent transmitters do not exceed regulatory limits when operating together. If the peak location distance ratio is large, the fields do not overlap and the individual SAR values can be evaluated independently. A small ratio indicates overlapping fields, requiring a more complex sum of SAR distributions.
Assessment Method
Compliance limits determine whether a device requires hardware modifications or can be certified with current power settings. Testing agencies set a specific threshold for the peak location distance ratio to classify the interaction between radiating elements. This classification streamlines the certification process by avoiding unnecessary composite SAR scans when the isolation is sufficient.