Physical units to report intensity of electromagnetic wave

Abstract

The aim of this work is to propose a consensus to scientific community that handles personal exposimeters, which measure intensity of an electromagnetic wave (W/m²). To express the intensity of an electromagnetic wave there is a duality in the way of expressing it. Some scientists prefer to use W/m² while others use V/m, which is a unit of the electric field. There is also a duality in the name, sometimes it is called it power flux density and some other times, wave intensity. We believe that this second name is more appropriate from the point of view of physics. We suggest expressing intensity of an electromagnetic wave in W/m² instead of giving the value of their electric field which is measured in V/m. There is a quadratic relation between electric field and intensity of the wave, and it is necessary to do a mathematical operation, so in our opinion, it is preferable to use W/m² which directly gives us the value of the measured intensity. Furthermore, if the intensity is very low, it may be expressed in μW/m² and with only three significant figures, due to sensitivity of the current exposimeters used.

Keywords: Electromagnetic field; Electromagnetic wave; Near-Field and Far-Field; Units; Wave intensity.