[Antennes 4G pour lunettes connectées et indices DAS associés]
Dans cet article, nous présentons tout d'abord une étude de faisabilité d'antennes 4G (700–960 MHz et 1,7–2,7 GHz) intégrables dans une paire de lunettes connectées. Cet objet est destiné à être connecté aux réseaux de communication cellulaires de dernière génération ainsi qu'aux réseaux personnels de type WLAN. Le concept antennaire d'élément de couplage associé à un circuit d'adaptation est ainsi évalué en termes de coefficient de réflexion et d'efficacité rayonnée lorsque les lunettes sont positionnées sur la tête de l'utilisateur. Nous présentons également l'analyse dosimétrique des prototypes optimisés pour le fantôme homogène SAM et le fantôme évolué hétérogène Visible Human (VH) : les niveaux de DAS dans ces deux fantômes sont simulés et comparés aux normes internationales. Dans un second temps, nous présentons les premiers résultats expérimentaux obtenus à partir de prototypes fabriqués par une imprimante 3D pour la monture des lunettes et des procédés de réalisation classique pour les PCB qui accueillent les éléments de couplage antennaire et leur circuit d'adaptation. Les valeurs théoriques et expérimentales concernant les coefficients de réflexion et les efficacités totales des antennes sont en très bon accord, attestant ainsi une efficacité rayonnée variant de 10 à 12% en bande basse et de 20 à 35% en bande haute. Cependant, les simulations dosimétriques révèlent des niveaux de DAS qui peuvent dépasser les normes du fait des fortes efficacités rayonnées obtenues avec les antennes conçues, notamment avec des pics préoccupants observés au niveau de l'œil.
In this paper, we first present a feasibility study to design 4G antennas (700–960 MHz and 1.7–2.7 GHz) for eyewear devices. Those eyewear devices should be connected to the last generation cellular networks, Wireless Local Area Networks or wireless hotspots. Three coupling element type antennas with their matching networks are evaluated in terms of reflection coefficient and total radiation efficiency when the eyewear is placed on the user's head. We also present Specific Absorption Rate (SAR) simulations when the eyewear is positioned over a homogeneous SAM phantom and over a heterogeneous VH (Visible Human) phantom: the SAR levels are compared to international limit values. In a second step, we present experimental results obtained with 3D printed eyewear and coupling elements etched on a classical PCB substrate where the matching circuits are optimized close to the feeding point of the coupling element. Simulated and measured values are in very good agreement: 7 to 16% and 9 to 35% total efficiency are respectively obtained for the low- and high-frequency bands. However, simulated SAR values are somewhat higher than authorized levels with preoccupant high electromagnetic field distribution close to the eye of the user.
Mot clés : Lunettes connectées, Élément de couplage, LTE, DAS
@article{CRPHYS_2015__16_9_836_0,
author = {Aykut Cihangir and Will Whittow and Chinthana Panagamuwa and Gilles Jacquemod and Fr\'ed\'eric Gianesello and Cyril Luxey},
title = {4G antennas for wireless eyewear devices and related {SAR}},
journal = {Comptes Rendus. Physique},
pages = {836--850},
publisher = {Elsevier},
volume = {16},
number = {9},
year = {2015},
doi = {10.1016/j.crhy.2015.10.009},
language = {en},
}
TY - JOUR AU - Aykut Cihangir AU - Will Whittow AU - Chinthana Panagamuwa AU - Gilles Jacquemod AU - Frédéric Gianesello AU - Cyril Luxey TI - 4G antennas for wireless eyewear devices and related SAR JO - Comptes Rendus. Physique PY - 2015 SP - 836 EP - 850 VL - 16 IS - 9 PB - Elsevier DO - 10.1016/j.crhy.2015.10.009 LA - en ID - CRPHYS_2015__16_9_836_0 ER -
%0 Journal Article %A Aykut Cihangir %A Will Whittow %A Chinthana Panagamuwa %A Gilles Jacquemod %A Frédéric Gianesello %A Cyril Luxey %T 4G antennas for wireless eyewear devices and related SAR %J Comptes Rendus. Physique %D 2015 %P 836-850 %V 16 %N 9 %I Elsevier %R 10.1016/j.crhy.2015.10.009 %G en %F CRPHYS_2015__16_9_836_0
Aykut Cihangir; Will Whittow; Chinthana Panagamuwa; Gilles Jacquemod; Frédéric Gianesello; Cyril Luxey. 4G antennas for wireless eyewear devices and related SAR. Comptes Rendus. Physique, Volume 16 (2015) no. 9, pp. 836-850. doi : 10.1016/j.crhy.2015.10.009. https://comptes-rendus.academie-sciences.fr/physique/articles/10.1016/j.crhy.2015.10.009/
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