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
Aykut Cihangir 1 ; Will Whittow 2 ; Chinthana Panagamuwa 2 ; Gilles Jacquemod 1 ; Frédéric Gianesello 3 ; Cyril Luxey 1
@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/
[1] http://www.google.com/glass/start/
[2] Hooked loop antenna concept for bluetooth headset applications, AP-S 2004 ( July 2004 ), pp. 3521-3524
[3] Matching a bluetooth headset antenna on a small system ground by using a conductive wire, Microw. Opt. Technol. Lett., Volume 51 (2009) no. 12, pp. 2802-2805
[4] Study of the bluetooth headset antenna with the user's head, Microw. Opt. Technol. Lett., Volume 49 (2007) no. 1, pp. 19-23
[5] Behavior of several antenna topologies near the human head at the 2.4–2.5 GHz band, Microw. Opt. Technol. Lett., Volume 54 (2012) no. 8, pp. 1911-1916
[6] Feasibility study of 4G cellular antennas for eyewear communicating devices, IEEE Antennas Wirel. Propag. Lett., Volume 12 (2013), pp. 1704-1707
[7] Resonator-based analysis of the combination of mobile handset antenna and chassis, IEEE Trans. Antennas Propag., Volume 50 (2002) no. 10, pp. 1433-1444
[8] Effect of field enhancement due to the coupling between a cellular phone and metallic eyeglasses, Microw. Opt. Technol. Lett., Volume 48 (2006) no. 1, pp. 63-65
[9] A study of changes to specific absorption rates in the human eye close to perfectly conducting spectacles within the radio frequency range 1.5 to 3.0 GHz, IEEE Trans. Antennas Propag., Volume 52 (2004) no. 12, pp. 3207-3212
[11] IEC, Human exposure to radio frequency fields from hand-held and body-mounted wireless communication devices—human models, instrumentation, and procedures—part 1: procedure to determine the specific absorption rate (SAR) for hand-Held devices used in close proximity to the ear (frequency range of 300 MHz to 3 GHz), IEC 62209-1:2005, 2005.
[12] IEEE, IEEE recommended practice for determining the peak spatial-average specific absorption rate (SAR) in the human head from wireless devices: measurement techniques, IEEE Std 1528, 2003.
[13] et al. Comparisons of computed mobile phone induced SAR in the SAM phantom to that in anatomically correct models of the human head, IEEE Trans. Electromagn. Compat., Volume 48 (2006) no. 2, pp. 397-407
[14] et al. An international interlaboratory comparison of mobile phone SAR calculation with CAD-based models, IEEE Trans. Antennas Propag., Volume 52 (2010) no. 4, pp. 804-811
[15] Specific absorption rate and current densities in the human eye and head induced by the telemetry link of an epiretinal prosthesis, IEEE Trans. Antennas Propag., Volume 57 (2009) no. 10, pp. 3110-3118
[16] On the effects of straight metallic jewelery on the specific absorption rates resulting from face-illuminating radio communication devices at popular cellular frequencies, Phys. Med. Biol., Volume 53 (2008), pp. 1167-1182
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