Maximum Exposure Assessment of millimeter-Wave Array Antennas

5G user equipment makes use of array antennas to form beams according to a predefined codebook. In this paper, we provide an algorithm to determine upper bounds of maximum power density of array antennas from a set of electromagnetic field (EMF) realized by independent configurations. The method uses only EMF of the device under test (DUT) operating at configurations taken from the actual codebook and does not require absolute reference phase to be preserved between configurations. In all cases, the algorithm provides a conservative estimate of worst-case power density with limited overestimation. The proposed method therefore provides a practical way to assess compliance of millimeter-wave array antennas with as few as n+1 field measurements and is a valuable step forward for the standardization of RF EMF exposure compliance procedures of 5G devices.