Multi-Antenna SAR Estimation in Linear Time

Specific Absorption Rate (SAR) is a measure used by regulatory agencies for determining the exposure safety compliance of portable wireless transmitting devices. For devices with multiple transmitter chains operating at a single frequency, determining compliance is complicated by the fact that testing needs to cover all possible combinations of transmissions from all antennas. We give a compliance test of multi-antenna devices with measurement time which is linear in the number of antennas N. The proposed test requires 7N -12 measurements per probe location for N ≥ 3, independently of the number and type of transmitted signals. We evaluate the performance of the proposed test for noisy SAR measurements.