Wearable multi-antenna multi-band measurement system for personal radio-frequency exposure assessment

Abstract

Rising concern about the potential harmfulness of human radio-frequency exposure causes scientists to be highly interested in measuring these exposure levels. The set of measured signal levels on a map of locations is then used for epidemiological research, looking for correlation to the incidence of certain illnesses. Currently available hand-held exposimeters have the disadvantage that the measured signal levels are often significantly different from the exposure to which the human body is actually subjected. Therefore, a personal distributed exposimeter was developed and documented in this paper. Multiple on-body antennas are employed in order to measure the electromagnetic field strengths directly on the body. In this design, 11 commonly used frequency bands are measured, with front and back textile antennas for each of those bands. These 22 antennas are implemented in substrate-integrated-waveguide technology, thereby combining a compact size with a large bandwidth. The measurement system operates autonomously, through measurement, control and data-logging circuitry directly integrated onto the antennas. The textile-antenna based nodes are unobtrusively integrated into a garment, resulting in maximum comfort for the user. A measurement campaign using the system is currently underway in a number of European countries, yielding a large amount of valuable and unique data for epidemiological analyses.