Conduct, Results and Analysis of Biennial Proficiency Tests of SAR Measurements

Specific absorption rate (SAR) measurements are routinely performed on wireless devices to assess its exposure. Proficiency tests (PTs) through interlaboratory comparison of SAR were conducted in 2017 and 2019. In total, 210 measurement results were provided in terms of best estimate and uncertainty. Firstly, the performance of all the participating laboratories are evaluated. Then this paper presents a comprehensive analysis of the PT results from three perspectives as follows, the applicability of performance statistics D% and z-score, the consistency of the PT results in 2017 and 2019, and the satisfaction rates of the PT results for GSM and LTE. Furthermore, to analyze the impacts of measurement conditions on the SAR, cross-correlations are calculated. It is shown that the SAR measurement is sensitive to the tissue equivalent liquid but insensitive to the environment temperature.