Amplitude probability distribution measurement for electric field intensity assessment of cellular-phone-base stations

In compliance assessments of radio-frequency exposure from cellular-phone-base station antennas, the root of 6-min time average of the squared electric fields is commonly required. Under the assumption that the time-varying electric fields belong to an ergodic process, a new approach has been proposed to estimate the 6-min time average from the ensemble average of the squared electric fields based on amplitude probability distribution (APD) measurements for a shorter time, much less than 6 min. The usefulness of the approach has been demonstrated at the 800-MHz band and the 1.5-GHz band, and the results have shown that by using a fast sampling rate, 1-min APD measurements could give a good estimate of the 6-min time average with an accuracy of within +/- 10%.