Limitations of using electro-optical probes for the measurement of the electromagnetic field emitted by the new generations of wireless communication devices

Abstract

The rapid evolution of communication standards caused a paradigm shift in electromagnetic field (EMF) measurement campaigns, as exposure is more likely to take place in the proximity of the device. With the increased spatial variability of EMF exposure, electro-optical (EO) technology stands out as a promising alternative to conventional near field measurement instrumentation due to their miniature sizes and dielectric structure that does not interfere with the measured field. Motivated by the recent progress in the EO sensing technology, it is this article purpose to quantify the limitations of using a set of commercially available EO probes for measurement of EMF emitted by an IEEE 802.11ax router and a VoLTE mobile phone. To our knowledge, this is the first attempt to characterize the capabilities of this emerging sensing technology for EMF exposure assessment in real world communication situations. Present findings suggest that the sensitivity of the investigated EO probes is insufficient for measuring broadband signals at field levels that characterize state-of-the-art communication devices used by the public in common usage scenarios. This work also documents the EO probes suitability and response with respect to frequency, electric field strength and signal bandwidth.