Electromagnetic Waves 2. Pierre-Noël Favennec

or measuring an electromagnetic field is carried out via current or voltage measurements. The electromagnetic field located in one place is the set of vector fields (

,

and

. Subsequent processing can, if useful, select the different frequencies.

      In our everyday life, the environmental electromagnetic field does not arise from a single source. There are fields of natural origin (the sun, galaxy, geomagnetism, etc.) and those of human origin (household materials, transport, telecommunications, energy supply, etc.). Each point on the planet is subjected to a fairly intense electromagnetic “bath” depending on its location. The drawing below, envisaged by Michel Urien, shows that we are all “willingly” bathed in these electromagnetic waves. Let us try to understand our electromagnetic environment!

Figure P.1. A wave bath envisaged by Michel Urien1

      This referenced work, presented in two inseparable volumes, is essential for any student, engineer or researcher wishing to understand electromagnetism and all the technologies derived from it.

      Volume 1 is oriented towards the basic phenomena explaining electromagnetism: the famous Maxwell equations – essential to know – then the propagation phenomena of electromagnetic waves. It only concerns non-ionizing radiation, which is radiation from waves whose energies are insufficient to ionize an atom, that is to say incapable of removing an electron from matter. This excludes all radiation with an energy greater than 12.4 eV, that is that generated by X-ray and gamma ray emitters. This work is made up of two chapters.

      In Chapter 1, Ibrahima Sakho presents the Maxwell equations as clearly as possible. These equations are essential to comprehensively approach electromagnetism and all its derived fields such as radioelectricity, photonics, geolocation, measurement, telecommunications, medical imagery, radio astronomy, etc.

      In Chapter 2, Hervé Sizun describes the propagation phenomena of electromagnetic, radio and photonic waves. Many factors, often complex, must be taken into account to properly understand these propagation problems in free and sometimes confined spaces.

      In Volume 2, Jean-Pierre Blot, expert in radio antennas of all configurations, directs his analysis towards antennas, essential elements for the detection of electromagnetic waves, their characterization and use. This volume is intended to describe what an effective antenna should be, according to various parameters and conditions of use. It does not address the detection problems specific to photonics. Photonics and these detection problems will be seen in a future publication of the “Waves” series.

      Important appendices with essential information, presenting in particular mathematical tools, complete these two volumes.

      References

      Cartini, R. (1993). Panorama encyclopédique des sciences. Belin, Paris.

      de Fornel, F., Favennec, P.-N. (eds) (2007). Mesures en électromagnétisme. Revue RS série I2M, 7(1–4).

      Favennec, P.-N. (2008). Mesures de l’exposition humaine aux champs radio-électriques – Environnement radioélectrique. Techniques de l’Ingénieur, Saint-Denis.

      Serres, M., Farouki, N. (1997). Dictionnaire des sciences. Flammarion, Paris.

      1 1 Source: www.armorscience.com.