Effect of Time-Averaging of Pulsed Radio-Frequency Signals on Specific Absorption Rate Measurements

The effect of the time-averaging of pulsed radio-frequency (RF) signals on the specific absorption rate (SAR) measurements is studied. Probes employed for SAR measurements are usually calibrated using continuous wave (CW) signals. The response of such probes is different when measuring pulsed RF waveforms. The CW probe calibration data are applicable to the average power of the pulsed RF signal. The time-domain response of a commercially available off-the-shelf SAR probe to a global system for mobile communication signal is investigated. The error induced by the time-averaging process is evaluated. The ensemble average procedure is compared to the alternative peak detection method valid for signals with known duty cycle. The analysis can be extended to other pulsed RF waveforms with specifications that satisfy the time-domain characteristics of the probe.