Experimental Comparison of Extrapolation Techniques for 24-Hours Electromagnetic Fields Human Exposure Evaluation to UMTS and LTE Base Stations

The compliance of cellular base stations electromagnetic field emissions with 24-hours exposure limits generally requires adopting suitable extrapolation techniques able to provide an upper boundary to the emitted power. As for 3
^rd
and 4
^th
generation cellular systems, the technical standards describing the related measurement methods allows using either Spectrum Analyzers or Vector Spectrum Analyzers. The latter ones are preferable because of their enhanced capability to isolate the single base station contributions. Nevertheless, Spectrum Analyzers are the most widespread measurement instruments adopted by technician operating in such a framework. Therefore, it could be useful to quantify the expected overestimation with respect to the Vector-type instruments. To this aim, in this paper an experimental comparison between the results achieved by applying extrapolation techniques with both acquisition devices is performed. To verify the results' repeatability, such analyses have been carried out in different hours of the day and in different days. Our findings prove how Spectrum Analyzers generally overestimate the electric field magnitude with respect to Vector Analyzers even if different behaviors have been observed with respect to the different cellular systems.