4G antennas for wireless eyewear devices and related SAR

This article was published in Comptes Rendus Physique [© Elsevier France] and the definitive version is available at: http://dx.doi.org/10.1016/j.crhy.2015.10.009In 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

Evaluation de la technologie CMOS SOI haute résistivité pour application RF jusqu'en bande millimétrique

Les transmissions sans fi] n'ont cessé de prendre un essor considérable, que ce soit pour les applications spatiales, les radiocommunications mobiles ou les communications à courtes portées. Depuis quelques années, avec la montée en fréquence des composants, la technologie Silicium est présente dans. le domaine des radiofréquences et des hyperfréquences. Les circuits intégrés micro-ondes nécessitent des composants actifs performants pour des conditions de faibJe polarisation. Mais il apparaît également essentiel de proposer dans le même temps des composants passifs performants afin de pouvoir intégrer toutes les fonctions RF nécessaires Ce dernier point représente le principal écueil auquel les technologies silicium ce sont heurtées de part la nécessité d'utiliser des substrats à pertes afin de pouvoir gérer les probJèmes de latch up . Dans cette thèse, nous évaluerons les potentialités RF et millimétriques offertes par les technologies SOI de part leur compatibilité avec des substrats Hautement Résistifs (HR). Après avoir introduit le contexte général de l'étude nous investiguerons les performances offertes par les composants passif intégrés en technologie SOI HR. Ces composants seront alors utilisés dans le cadre de la réalisation de circuits passifs afin de valider ces composants développés et leurs modèles. Nous nous intéresserons alors à l'évolution des performances en bruit du transistor MaS. Nous conclurons en présentant des réalisations d'amplificateurs faible bruit afin de pouvoir effectuer une comparaison entre technologie SOI et silicium standard afin de dégager les potentialités millimétriques offertes par les technologies SOI HR.The wireless transmissions increase in a spectacular way, such as in the spatial applications, the mobile communication systems or the short range communications. Since few years, with the work frequency growth ofthe Silicon components, the Silicon technology is present in the radio and high frequency fields. The microwave integrated circuits need high performance components with low bias conditions. But it appears also essential to offer in the same time high performance passive components in order to be able to integrate an necessary RF functions. This Jast point remains the main limitation faced by standard silicon technologies, since they have to use lossy substrate (mainly to be able to manage "Jatch up" issue). ln this thesis, we wiIJ evaluate RF and minimeter wave potentialities offered by SOI technologies due to their compatibility with High Resistivity substrate. After having introduced the general context of this study we win investigate the performances offered by passive components integrated on HR SOI, while trying to propose dedicated èomponents which could take the best advantage ofhigh resistivity. These components win then be used within the achievement of passive circuits in order to validate those deveJoped components and their mode!. We wiIJ focus then on the evolution of the performances in noise of MaS transistor. Finany, we end up this manuscript by presenting achievements of Low Noise Amplifiers in order to fun fin a benchmarking between HR SOI and standard silicon technology in order to discuss the millimeter wave potentialities open by HR sa!.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Réalisation et caractérisation de coupleurs à réseau en technologie photonique sur silicium

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Innovative Tunable Antenna Solution Using CMOS SOI Technology

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Antenne LDS Innovante pour des Applications 4G

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Innovative LDS Antenna for 4G Applications

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4G Antenna Tuner Integrated in a 30 nm CMOS SOI Technology

International audienceIn order to counteract antenna impedance mismatch due to interaction with environment, one solution is to use a tuner between the front end module and the antenna. In this paper, a 4G antenna tuner integrated in STMicroelectronics 130 nm CMOS SOI technology and operating between 2500 MHz and 2690 MHz is described. Thanks to high power CMOS SOI Digitally Tunable Capacitances (DTCs), the proposed tuner is able to match to 50 Ω an antenna presenting a VSWR degraded up to 5:1.Minimal input reflection coefficient of -10 dB is reached and promising insertion losses are obtained (minimal losses of 3.5 dB for an antenna with initial VSWR of 5.1)

Improved Measurement Accuracy of Probe-Fed mm-Wave Antennas Using the Three Method

International audienceIn this letter, we present a method to extract the scattering parameters of a microelectronic probe used to feed on-chip or in-package antennas at millimeter-wave frequencies. It is especially important to take into account these losses in the calibration procedure necessary for the extraction of the antenna gain. We are specifically demonstrating that these losses are positively or negatively impacted, depending on the impedance value of the input impedance of the antenna connected to the probe. Theory is detailed and examples are given to illustrate the importance of taking into account those losses with precision. From the S-parameters of the probe and the measurement of the reflection coefficient of the antenna, we can compute the gain from the measured realized gain. An accuracy improvement of 15% is shown for the gain of the presented antenna

10-Gb/s Indoor THz Communications Using Industrial Si Photonics Technology

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Mono-block Dielectric Resonator Antenna with Incorporated Excitation for 60 GHz Integrated Systems

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