Les ondes millimétriques (5G) chauffent les insectes Imprimer
Écrit par Eric   
Lundi, 15 Juin 2020 22:57
(30/3/18) Une étude théorique publiée le 2 mars 2018 dans Nature, Scientific Reports montre l'effet des champs électromagnétiques de radiofréquences de 2 à 120 ghz sur les insectes. Tous les insectes ont montré une augmentation générale de la puissance RF absorbée à et au-dessus de 6 GHz, par rapport à la puissance RF absorbée au-dessous de 6 GHz.
Nos simulations ont montré qu'un décalage de 10% de la densité de puissance incidente vers des fréquences supérieures à 6 GHz entraînerait une augmentation de la puissance absorbée entre 3 et 370%. Cela pourrait entraîner des changements dans le comportement, la physiologie et la morphologie des insectes au fil du temps en raison d'une augmentation des températures corporelles, due au chauffage diélectrique. Les insectes étudiés inférieurs à 1 cm présentent un pic d'absorption à des fréquences (supérieures à 6 GHz), qui ne sont actuellement pas souvent utilisées pour les télécommunications, mais devraient être utilisées dans la prochaine génération de systèmes de télécommunications sans fil. (ndlr 5G, satellites ka-sat, satellites starlink, faisceaux hertziens entre sites)
 
Exposure of Insects to Radio-Frequency Electromagnetic Fields from 2 to 120 GHz
Arno Thielens, Duncan Bell, David B. Mortimore, Mark K. Greco, Luc Martens & Joseph Wout 
Scientific Reports volume 8, Article number 3924 (2 march 2018)
  
Abstract
Insects are continually exposed to Radio-Frequency (RF) electromagnetic fields at different frequencies. The range of frequencies used for wireless telecommunication systems will increase in the near future from below 6 GHz (2G, 3G, 4G, and WiFi) to frequencies up to 120 GHz (5G). This paper is the first to report the absorbed RF electromagnetic power in four different types of insects as a function of frequency from 2 GHz to 120 GHz. A set of insect models was obtained using novel Micro-CT (computer tomography) imaging. These models were used for the first time in finite-difference time-domain electromagnetic simulations. All insects showed a dependence of the absorbed power on the frequency. All insects showed a general increase in absorbed RF power at and above 6 GHz, in comparison to the absorbed RF power below 6 GHz. Our simulations showed that a shift of 10% of the incident power density to frequencies above 6GHz would lead to an increase in absorbed power between 3–370%.
 
Introduction
 
Radio-Frequency (RF) electromagnetic fields (EMFs) enable wireless communication between billions of users worldwide. Presently, this mainly occurs at RF frequencies located between 100 MHz and 6 GHz1. Wireless telecommunication base stations are the dominant sources of outdoor RF-EMFs1. Humans and animals alike are exposed to these fields, which are partially absorbed by their bodies, e.g. reported for insects in2. The absorbed dose depends on the frequency3,4, and can be strongly enhanced when a full-body or partial-body resonance occurs3. This RF absorption has already been studied for particular insects at different individual frequencies: 27 MHz5,6, 900–915 MHz6,7,8, and 2450 MHz9.
This absorption may cause dielectric heating10. Heating affects insect behavior, physiology, and morphology11. Reviews of studies that investigate RF heating of insects are presented in12,13,14. Other authors focus on environmental RF exposure of insects15,16 or expose insects to RF radiation in order to investigate potential biological effects17,18. Studies on non-thermal effects of exposure to RF-EMF exist:19 presents a review of potential mechanisms for non-thermal effects and a review of non-thermal effects of EMF exposure wildlife is presented in20. Most existing studies focus on RF frequencies below 6 GHz. The same frequencies at which the current generations of telecommunication operate1. However, due to an increased demand in bandwidth, the general expectation is that the next generation of telecommunication frequencies will operate at so-called millimeter-wavelengths: 30–300 GHz21,22. Therefore, future wavelengths of the electromagnetic fields used for the wireless telecommunication systems will decrease and become comparable to the body size of insects and therefore, the absorption of RF-EMFs in insects is expected to increase. Absorption of RF energy was demonstrated in insects between 10–50 GHz23, but no comparison was demonstrated with the RF absorption at frequencies below 10 GHz. The radar cross section of insects has been determined above 10 GHz, but this quantity includes both scattering and absorption24. It is currently unknown how the total absorbed RF power in insects depends on the frequency to which they are exposed.
Most of the previously cited studies depend on measurements using RF equipment such as antennas, waveguides, and dielectric probes to determine the absorption of RF-EMFs in insects. An alternative approach would be to use numerical simulations. This approach was previously used to determine the absorption of RF-EMFs in humans and requires numerical models or phantoms25,26,27,28.
Techniques for creating heterogeneous, three-dimensional insect models with micrometer resolution have previously been demonstrated in29.
However, up to now, insect phantoms have not been used in electromagnetic simulations.
The aims of this study were to, for the first time, numerically evaluate RF-EMF absorption in real models of insects and to determine a potential difference in RF absorption in insects due to current and future telecommunication networks. To this aim, we studied the absorbed RF power in four different insect models obtained using micro-CT imaging as a function of frequency in a broad band, 2 GHz up to 120 GHz, that covers both the existing and the foreseen future wireless telecommunication bands. Voxelling precision in the order of 5–20 μm is obtained, required for accurate electromagnetic simulations.
 
conclusion

This could lead to changes in insect behaviour, physiology, and morphology over time due to an increase in body temperatures, from dielectric heating. The studied insects that are smaller than 1 cm show a peak in absorption at frequencies (above 6 GHz), which are currently not often used for telecommunication, but are planned to be used in the next generation of wireless telecommunication systems. At frequencies above the peak frequency (smaller wavelengths) the absorbed power decreases slightly.

https://www.nature.com/articles/s41598-018-22271-3

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Mise à jour le Lundi, 15 Juin 2020 23:11