Meaning
Summing instantaneous radio frequency exposure contributions across multiple transmitting antennas relative to their respective regulatory limits quantifies total electromagnetic exposure in multi-transmitter devices. Calculation frameworks using normalized exposure ratio combine specific absorption rate metrics below 6 gigahertz with power density metrics above 6 gigahertz into a single dimensionless index. Values below unity confirm that total multi-band emissions remain within permissible legal boundaries.
The calculation governs simultaneous multi-transmitter compliance but does not evaluate single-frequency power output limits.
Mathematical Formulation
Ratios for each active transmitter combine measured power levels divided by maximum allowable exposure thresholds. Computing normalized exposure ratio involves adding SAR exposure ratios from sub-6 gigahertz transmitters to power density ratios from millimeter-wave transmitters. Scaling factors adjust transmitter weights based on dynamic duty cycles.
Firmware Tracking
Real-time power management algorithms evaluate total device output every frame to prevent threshold exceedance. Embedded firmware monitoring normalized exposure ratio dynamically scales transmitter output power across active cellular and Wi-Fi links. Power allocations shift between antennas based on proximity sensor inputs and data traffic demand.
Regulatory Boundary
Certification authorities mandate combined exposure evaluations for all devices operating multiple active transmitters simultaneously. Test reports log normalized exposure ratio values across realistic operational scenarios to demonstrate compliance under worst-case transmission duty cycles. Device approvals require continuous compliance across all supported band combinations.
