Evaluation Method for Whole-Body Exposure from 5G Base Stations using Superposition

For high frequencies such as the 28 GHz band used in 5 G mobile communication systems, base stations are installed closer to users than conventional tower-type stations, and beamforming is utilized to compensate for the short propagation distance. Evaluating electromagnetic wave exposure to the human body is important, with the worst-case exposure level being the key factor. Therefore, it is necessary to calculate and compare the exposure levels from different beam directions radiated by base stations located a few meters away from the human body. This study aims to accelerate each exposure evaluation during the exhaustive search for worst-case beam configuration. We investigated a method to calculate exposure levels based on the fact that radiations from an arbitrary antenna can be expressed as a superposition of spherical waves [1]. Pre-calculating exposure data for spherical waves requires a large-scale computing environment. However, the superposition evaluation can be performed on a workstation, reducing the computational resources needed for exposure evaluation for each radiation pattern.