Study on the Appropriate Measurement Spacing for EMF Installation Compliance Assessments of a 3.5 GHz 5G Base Station

The number of fifth generation (5G) base stations (BSs) installed for commercial services continues to increase in South Korea since the first 5G rollout of the 3.5 GHz band in 2019. However, this will cause a rapid increase in the cost and effort required for an electromagnetic field (EMF) installation compliance measurements of a 5G BS. This paper studies an appropriate measurement spacing for EMF installation compliance assessments of a 3.5 GHz 5G BS. Ray-tracing simulations based on the ray frustum technique are performed for three installation scenarios according to the accessibility categories provided in the International Telecommunication Union-T K.52 recommendation to observe the power density exposure trends. An interference analysis using the two-ray propagation model indicates that the spacing of 1 m can be suitable for the installation compliance of a 5G BS above 3 GHz. In addition, it was found that this spacing could be also applied up to the higher frequency of 7.125 GHz, the upper limit of Frequency Range 1 defined in the 3rd Generation Partnership Project specification. Measurements based on two different 5G signal extrapolations using the Synchronization Signal Block were conducted to validate the spacing of 1 m for a 3.5 GHz 5G BS established by simulation studies.