Effective SSB Beam Radiation Pattern for RF-EMF Maximum Exposure Assessment to 5G Base Stations Using Massive MIMO Antennas

摘要

Current extrapolation procedures for the assessment of theoretical maximum RF-EMF exposure to 5G massive MIMO base stations consider the antenna gain difference between SSB and traffic beams. The procedure strongly relies on the provided antenna patterns obtained under ideal conditions, but being distorted and smoothed in practice. In this paper, we investigate the impact of ground reflections (for different ground materials) as well as the vertical sweeping of the measurement antenna (in order to find the local maximum exposure) on the effective base station antenna pattern. It shows that for base station antenna heights ≥30 m, ground reflection dominates the impact and leads to an increase of null levels in the normalized antenna pattern to around -30 dB in case of concrete ground and furthermore, to a slight increase of side lobe levels. Both ground reflection and vertical antenna sweeping additionally lead to a broadening of the side lobes.