78 research outputs found
High frequency operation of an integrated electro-absorption modulator onto a vertical-cavity surface-emitting laser
We present in this paper the vertical integration of an electro-absorption modulator (EAM) onto a vertical-cavity surface-emitting laser (VCSEL). We discuss the design, fabrication, and measured characteristics of the combined VCSEL and EAM. We previously demonstrated a standalone EAM with an optical bandwidth around 30 GHz. In this paper we present for the first time an optical bandwidth of 30 GHz for an EAM integrated onto a VCSEL. This device exhibits single-mode operation and a very low chirp, below 0.1 nm, even with a modulation depth of 70% which makes this device very competitive for high-speed communications in data centers
An Original SiGe Active Differential Output Power Splitter for Millimetre-wave Applications
This paper deals with an original design of an active power splitter featuring a differential output presenting a greatly enhanced even mode rejection.The proposed circuit consists in two cascaded common emitter and common collector differential pairs.For achieving the best performance,it is shown that each of these two differential pairs requires a specific common node to ground impedance that is discussed.The circuit has been implemented on a 0.25 ”m SiGe BiCMOS process and exhibits anticipated phase and amplitude broadband unbalance less than 6.5 ° and 0.6 dB respectively all over the 6 -27 GHz frequency range.At 20 GHz,a common mode rejection ratio better than 43 dB is predicted,i.e.a maximum 0.12 dB /0.35 ° output signal unbalance
Optimisation de structures différentielles en technologie SiGe pour applications en bande millimétrique. Application à la conception d'un mélangeur doublement équilibré en bande K
Present work contributes to BiCMOS SiGe monolithic technology evaluation for future high-performance millimetre-wave telecommunications applications. For theses applications, balanced circuit architectures are very attractive according to their low noise susceptibility and their EMI radiation immunity. However, as frequency is increased, passive devices losses raise and classical differential amplifier topologies cannot achieve sufficiently well balanced operation. Thus, our main purpose is to propose innovative differential topologies suitable for millimetre-wave high-performance balanced circuits. Firstly, the evaluation of several interconnection technologies (microstrip, coplanar waveguide and coplanar strips) integrated on silicon substrate is presented. An inductor library then is designed for K and Ka frequency band operation. Enhanced performance inductors are issued from the analysis of losses mechanisms. A second part addresses the performance optimization of differential circuits for future applications in the 20-40 GHz frequency range. Firstly, we demonstrate that classical approaches for differential pair design lead to poor balanced behaviour in the millimetre-wave frequency band, because of intrinsic transistor characteristics. Original differential pair topologies are then proposed to overcome these drawbacks. These structures are then applied for the design of a 20 GHz active balun. Finally, a double balanced frequency converter from 20 GHz to 1 GHz is designed. The whole chip integrates the mixing cell and the three couplers. The characterization of this circuit demonstrates the usefulness of our choice for interconnections and confirms the great interest of developed original differential structures.Cette thĂšse apporte une contribution Ă l'Ă©valuation des potentialitĂ©s de filiĂšres SiGe de type BiCMOS pour les futures applications de tĂ©lĂ©communications en bande millimĂ©trique. Dans ce cadre, les topologies Ă©quilibrĂ©es ou diffĂ©rentielles sont trĂšs attrayantes, en raison de leur bonne immunitĂ© aux perturbations Ă©lectriques et Ă©lectromagnĂ©tiques. La montĂ©e en frĂ©quence des applications hyperfrĂ©quences sur silicium s'accompagne de nouvelles difficultĂ©s. Les pertes introduites par les Ă©lĂ©ments passifs augmentent et les performances des structures diffĂ©rentielles classiques chutent trĂšs rapidement. Il est alors nĂ©cessaire d'exploiter d'autres techniques et de rechercher des topologies innovantes permettant la rĂ©alisation de fonctions Ă©quilibrĂ©es performantes. Une premiĂšre partie est consacrĂ©e Ă l'Ă©valuation des potentialitĂ©s des diffĂ©rentes technologies d'interconnexions (microruban, guides coplanaires et lignes Ă rubans coplanaires) exploitables pour la conception de circuits monolithiques sur silicium. Dans un second temps, une bibliothĂšque d'inductances optimisĂ©es pour une utilisation en bande K et Ka est constituĂ©e. Les mĂ©canismes physiques Ă l'origine des pertes dans ce type d'Ă©lĂ©ment sont dĂ©taillĂ©s afin de dĂ©gager les solutions permettant d'amĂ©liorer leurs performances. Une deuxiĂšme partie traite de l'optimisation des performances des circuits diffĂ©rentiels pour les futures applications dans la gamme 20-40 GHz. Dans un premier temps, nous dĂ©taillons les caractĂ©ristiques hautes frĂ©quences du transistor qui pĂ©nalisent le fonctionnement d'une structure diffĂ©rentielle classique. Des topologies de structures diffĂ©rentielles originales permettant de rĂ©soudre ce problĂšme sont ensuite proposĂ©es. Ces structures sont appliquĂ©es Ă la conception d'un diviseur de puissance actif 180° original, optimisĂ© pour une frĂ©quence centrale de fonctionnement de 20 GHz. Enfin, un convertisseur de frĂ©quences 20 GHz vers 1 GHz a Ă©tĂ© conçu et rĂ©alisĂ©. Celui-ci intĂšgre, outre le mĂ©langeur, le s trois coupleurs actifs 180° nĂ©cessaires Ă la gĂ©nĂ©ration / recombinaison des signaux diffĂ©rentiels utiles au mĂ©langeur. La caractĂ©risation de ce convertisseur de frĂ©quences dĂ©montre la pertinence des configurations choisies pour les interconnexions ainsi que le grand intĂ©rĂȘt des structures diffĂ©rentielles originales mises en Suvre
Contribution Ă lâintĂ©gration des circuits micro-ondes et millimĂ©triques pour les tĂ©lĂ©communications
The work presented in this document deals with the integration of microwave and millimeter-wave circuits. It follows the global trend towards improvedperformances, miniaturized, low-power and cost-effective circuits. Our research activity includes both the integration of active circuits as well as passive components.The first given example proposes some solutions aimed for noise performance optimization of integrated RF power amplifiers whose non-linear operation translates the LF noise sources up to microwave frequencies.We then propose to use the passive mixer based on MOS transistors as a possible candidate for future flexible and reconfigurable radio architectures. The optimizations performed at the device level as well as circuit topology significantly push the maximum operating frequencies up to V and W bands through the implementation of sampling and sub-sampling techniques, which also significantly reduce mixerâs conversion losses.Finally, since the beginning of the microelectronic industry, the back-end-of-line is processed essentially in two dimensions, by stacking metal layers. We are developing an original approach that seeks to provide an additional degree of freedom by allowing the metalization of the sidewalls of a pillar of resin. This innovation, which has been patented, enables the fabrication of passive devices in three dimensions (3D), such as solenoids and RF transformers, for a very low cost. The successive improvements achieved in the fabrication process have led to extremely compact devices with performances that are currently at the level of the state of the art.Les travaux prĂ©sentĂ©s dans cette habilitation traitent de lâintĂ©gration des circuits micro-ondes et millimĂ©triques. Ils sâinscrivent dans une tendance mondiale dont les enjeux principaux sont lâamĂ©lioration des performances, la miniaturisation, la baisse de la consommation Ă©lectrique des circuits ainsi que la maĂźtrise des coĂ»ts. Notre activitĂ© de recherche porte donc tout naturellement Ă la fois sur lâintĂ©gration des circuits actifs et des composants passifs.Le premier exemple Ă©voquĂ© propose quelques pistes de travail visant Ă optimiser les performances en bruit des amplificateurs de puissance intĂ©grĂ©s dont le fonctionnement non-linĂ©aire tend Ă transposer les sources de bruit BF vers les frĂ©quences micro-ondes.Nous proposons ensuite dâemployer le mĂ©langeur passif Ă transistors MOS pour rĂ©pondre aux besoins de plus en plus forts qui sâexpriment en direction des architectures radio flexibles et reconfigurables. Les optimisations effectuĂ©es au niveau de la gĂ©omĂ©trie du composant et de la topologie du circuit repoussent significativement les frĂ©quences limites de fonctionnement (bandes V et W) grĂące Ă la mise en Ćuvre de techniques dâĂ©chantillonnage et de sous-Ă©chantillonnage qui rĂ©duisent Ă©galement les pertes de conversions.Enfin, la microĂ©lectronique fonctionne essentiellement Ă deux dimensions depuis son apparition en procĂ©dant Ă un empilement de couches mĂ©talliques. Depuis quelque annĂ©es, nous Ă©tudions une approche originale qui vise Ă dĂ©gager un degrĂ© de libertĂ© supplĂ©mentaire en permettant la mĂ©tallisation des flancs dâun pilier de rĂ©sine. Cette innovation, qui a Ă©tĂ© brevetĂ©e, autorise la fabrication de composants passifs en trois dimensions (3D), tels que des solĂ©noĂŻdes et des transformateurs RF, pour un coĂ»t trĂšs faible. Les amĂ©liorations successives du procĂ©dĂ© ont permis dâaboutir Ă des composants extrĂȘmement compacts avec des performances qui se situent actuellement au niveau de lâĂ©tat de lâart
Optimisation de structures différentielles en technologie SIGE pour applications en bande millimétrique (application à la conception d'un mélangeur doublement équilibré en bande K)
TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF
NMOS Device Optimization for the Design of a W-band Double-Balanced Resistive Mixer
Lettre pour IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS, acceptĂ©e pour publication le 11 juin 2014.International audienceThis letter describes the implementation of NMOS devices in a double-balanced resistive mixer whose operating frequency reaches device's cut-off frequency. Conversion gain, linearity and required LO power are analyzed regarding NMOS device geometry. This work is done using simple analytic formulas and validated by electrical simulations led on a ring mixer. As a result, a down-converter is designed using a 0.13 ÎŒm BiCMOS SiGe process. The circuit includes three surrounding amplifiers at RF, LO and IF terminals. Measurements indicate a conversion gain of 14.5 dB at 76.8 GHz, an output-referred 1dB compression point of â10 dBm and a DSB noise figure of 6.3 dB suggesting the interest of NMOS-based double-balanced passive mixers at such high frequencies
Conception et intégration "above IC" d'inductances à fort coefficient de surtension pour applications de puissance RF
TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF
Evolution Trends and Paradigms of Low Noise Frequency Synthesis and Signal Conversion Using Silicon Technologies
International audienceSilicon technologies for HF applications have been proven for more than two decades, and technologies have greatly evolved. Whether CMOS or BiCMOS technologies, the unique combination of radio frequency, baseband, and digital functions allow a very high level of integration. While it is possible to achieve fully integrated transceivers, the major advantages of these silicon technologies lie mainly in their unparalleled performance in the field of frequency synthesis and frequency conversion. We propose in this paper a review of the major results obtained on these RF components since the beginning of the 2000s, also considering the impact of the technology node. The back-end of line (BEOL) process on which depends the quality of microwave monolithic integrated circuits (MMICs) is briefly presented in the introductory part. If circuit performances are tightly bound to the active devices (i.e., the heterojunction bipolar transistor SiGe HBT or CMOS transistor), passive elements (i.e., quality factor of inductors and varactors, losses of transmission, or interconnection lines) as well as the definition of the substrate also play a major role. The core of the article is oriented toward the noise of synthesized signals and frequency conversion. Frequency synthesis is presented through the analog design of a voltage-controlled oscillator (VCO) or through the direct digital frequency synthesis (DDFS), for which respective figures of merit are presented and discussed in a second section. The spectral purity of the oscillators being decisive in the definition of the throughput of a link is approached through the comparison of different figures of merit (FoM) for a set of circuits achievements over the selected period. If the realization of free oscillators is closely bound to the phase-locked loop (PLL)-type control loop for VCOs, the DDFS solution provides more direct and more flexible alternative at first sight. Therefore, these two solutions are analyzed collectively. Finally, the oscillator integrated in the transmitter or receiver supplies the needed LO (local oscillator) power to the frequency mixer in the frequency conversion module: henceforth, the third part of this study focuses on high-frequency mixer realizations. We thus consider this LO power in some advanced figure of merit mentioned in the second section. The design trade-off of the mixer is presented in an approach combining LO (conversion gain, channel isolation, and phase noise) and RF (HF noise figure and channel isolation) constraints. The final section provides a summary of the results and trends mentioned in the paper
Low Cost SU8 Based Above IC Process for High-Q RF Power Inductors Integration
International audienceThis paper presents a new process for integration of high-Q RF power inductors above low resistivity silicon substrates. The process uses the SU8 resin as a dielectric layer. The aim of using the SU8 is to form thick dielectric layer that can enhance the performance of the inductors. The flexibility of the process enables the possibility to realize complex shaped planar inductors with various dielectric and metal thicknesses to meet the requirements of the application. Q values of 55 at 5GHz has been demonstrated for an inductance value of 0.8nH using a 60 ”m thick SU8 layer and 30 ”m thick copper ribbons
A Low-Loss 77 GHz Sub-Sampling Passive Mixer Integrated in a 28-nm CMOS Radar Receiver
International audienceThis paper demonstrates that using sub-sampling mixer topology can be the right choice to implement a millimeter-wave (mmW) receiver. In a 77 GHz radar receiver, it allows to reduce the burden of a 77 GHz LO distribution chain, in term of area and consumption, while preserving RF performances. Demonstration is done from two topologies of Ă3 sub-sampling mixers implemented in 28-nm FD-SOI CMOS technology. The best proposed passive mixer exhibits a-2.1 dB conversion gain (Gcv), a 1dB input-referred compression power (ICP1dB) of +3.5 dBm, and a 16.8 dB Single Side Band Noise Figure (NFSSB). The mixer LO signal shaping consumption is 32 mW on a 1.2 V supply while the passive mixer core does not require any DC power
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