Design and Implementation of A 6-GHz Array of Four Differential VCOs Coupled Through a Resistive Network

International audienceThis paper presents the design and the implementation of a fully monolithic coupled-oscillator array, operating at 6 GHz with close to zero coupling phase, in 0.25 μm BICMOS SiGe process. This array is made of four LC-NMOS differential VCOs coupled through a resistor. The single LC-NMOS VCO structure is designed and optimized in terms of phase noise with a graphical optimization approach while satisfying design constraints. At 2.5 V power supply voltage, and a power dissipation of only 125 mW, the coupled oscillators array features a simulated phase noise of -127.3 dBc/Hz at 1 MHz frequency offset from a 6 GHz carrier, giving a simulated phase progression that was continuously variable over the range -64° < Δphi <64 ° and -116° < Δphi < 116°. This constant phase progression can be established by slightly detuning the peripheral array elements, while maintaining mutual synchronization

Conception et implémentation d'un réseau composé de quatre VCOs couplés oscillant à 6 GHz

National audienceCe papier décrit la conception et l'implémentation d'un réseau d'oscillateurs couplés totalement intégré en technologie BiCMOS SiGe 0,25 μm. Ce réseau est constitué de quatre VCOs NMOS différentiels couplés au moyen d'une résistance. Pour une tension d'alimentation de 2.5V, une puissance consommée de 125 mW à une fréquence d'oscillation de 6 GHz, le réseau présente un bruit de phase de -127dBc/Hz à 1MHz de la porteuse et un déphasage qui varie de façon continue entre -64° et +64 ° et entre -116° et +116°

Graphical method for the phase noise optimization applied to a 6-GHz fully integrated NMOS differential LC VCO

International audienceThis paper describes the design and the optimization in terms of phase noise of a fully integrated NMOS Voltage Controlled Oscillator (VCO) using a 0.25 μm BICMOS SiGe process. A three-dimensional phase noise analysis diagram and a graphical optimization approach is presented to optimize the phase noise of the VCO while satisfying design constraints such as tank amplitude, power dissipation, tuning range and start up conditions. At 2.5 V power supply voltage, the optimized VCO features a simulated phase noise of -118 dBc/Hz at 1 MHz frequency offset from a 6.12 GHz carrier. The VCO is tuned from 6.1 GHz to 7.9 GHz with a tuning voltage varying from 0 to 2.5 V, and a power dissipation of only 7.4 mW

Failure analysis of shot–sleeves used in brass high pressure die–casting process

A failure investigation has been conducted on a two cases of shot-sleeve used in brass–die casting and made up of AISI H10 tool steels to study their failure mechanisms. The chemical composition of the shot–sleeves material and the hardness profiles were evaluated. A preliminary examination of shot–sleeves reveal the presence of cracks network on their inner surfaces which proves that thermal fatigue was probably the main cause of their failure. A Meticulous investigation of these damaged surfaces reveal the presence of an additional small zone cited in the vicinity of the plunger entry side. This zone presents several scratches sign of abrasive wear. Then, the measurement of the cracks length and their linear density along longitudinal and transversal cuts of the damaged shot–sleeve sample are carried out. Results show that the observed cracks network can be divided into two zones. The first one was the most damaged in terms of cracks density and length given that it is the first zone which enter in contact with the molten metal. However, the cracks network examined in the second zone appears to be superficial

Analysis and design of a coupled oscillators array integrated in silicon technology and applied to control linear antenna arrays

Le travail présenté dans ce mémoire traite de l’étude comportementale, de la conception et de la validation d’une nouvelle architecture, basée sur le couplage d’O.C.T différentiels, appliquée à la commande électronique de l’orientation du diagramme de rayonnement d’un réseau d’antennes linéaire. Après avoir optimisé la structure de l’O.C.T différentiel, qui constitue le corps du circuit de commande, selon une méthode graphique qui visualise les différentes contraintes imposées par le système afin de minimiser son bruit de phase et sa consommation, l’O.C.T à sorties différentielles a été réalisé en technologie NXP BiCMOS SiGe 0,25 μm puis mesuré en boîtier. Etant donné que la direction de rayonnement d’une antenne réseau dépend de la valeur du déphasage imposé entre les signaux envoyés sur deux antennes adjacentes, les équations théoriques modélisant deux O.C.T couplés et permettant d’extraire les amplitudes et le déphasage entre les différents signaux ont été décrites. La dernière étape a alors consisté en la réalisation de deux réseaux constitués respectivement de deux et de quatre O.C.T couplés au moyen d’une résistance puis d’un transistor MOS fonctionnant en zone ohmique. L’approche de couplage proposée a été validée en se basant sur les résultats de mesures effectués. De plus, l’impact de l’utilisation de structures différentielles sur la plage de déphasage obtenue et donc sur le dépointage réalisé a également été présenté ce qui nous a permis de conclure sur l’efficacité du circuit de commande proposé.The work presented in this thesis deals with the study, design, and validation of a new architecture based on the coupling of differential voltage controlled oscillators (VCO) applied to the beamsteering of a linear antenna array. After optimizing the differential VCO structure, with a graphical optimization approach while satisfying design constraints imposed, in order to minimize the phase noise and power consumption, the differential VCO was realized in NXP BiCMOS SiGe 0.25 µm process and then measured. Since the radiation direction of an antenna array depends on the phase difference imposed between the two signals on adjacent antennas, the theoretical equations modeling two coupled VCOs, and allowing the extraction of the amplitude and phase difference between the outputs signals have been presented. The last step was the realization of two arrays consisting respectively of two and four VCOs coupled through a resistor and a MOS transistor operating in the triode region. The proposed coupling approach is validated based on the obtained measurement results. Furthermore, the impact of the use of differential structures on the phase shift range obtained and thus on the beam-scanning range achieved was also presented allowing to conclude on the efficiency of the proposed architecture

Design and Implementation of A 6-GHz array of two Differential Oscillators Coupled Through a MOS transistor Network

International audienceDuring the past decade, coupled oscillators have shown their efficiency as simple methods for phase control in microwave antenna arrays, and hence as alternatives to conventional electronic beam steering methods. This paper describes the design and the implementation of a fully monolithic coupled-oscillator array, operating at 6 GHz in 0.25 μm BICMOS SiGe process. A novel and original method, based on the use of a MOS transistor, for coupling the differential oscillators is developed and presented. At 2.5 V power supply voltage, and a power dissipation of only 62.5 mW, the coupled oscillators array features a simulated phase noise of -124.8 dBc/Hz at 1 MHz frequency offset from a 6.01 GHz carrier, giving a simulated phase progression that was continuously variable over the range -84 ° < Δ phi < 84 ° and -96° < Δ phi < 96°

A fully monolithic 5.8 GHz low phase noise coupled VCO networkfor phased-array systems

International audienc

A Fully Integrated 5.78 GHz Array of two Differential Oscillators Coupled Through a MOS transistor Network

International audienceA fully monolithic coupled differential Voltage-Controlled-Oscillators (VCOs) network for phased-arrayapplications is presented in this paper. The proposed integratedVCO array, operating at 5.78 GHz is implemented on a 0.25 μmBiCMOS SiGe process and is made of two LC-NMOSdifferential VCOs coupled through a MOS transistor. At 2.5 Vpower supply voltage, and a power dissipation of 62.5 mW, thecoupled VCO array features a measured best case phase noise of-125.21 dBc/Hz at 1 MHz frequency offset from a 5.78 GHzcarrier

Couplage actif d’OCTs à 5.78 GHz pour pilotage d’antenne réseau

National audienceCe papier décrit la conception et l’implémentationd’un réseau d’oscillateurs différentiels couplés,totalement intégré en technologie BiCMOS SiGe 0,25μm. Ce réseau est constitué de deux OscillateursContrôlés en Tension (OCT) LC-NMOS différentielscouplés au moyen de transistors PMOS. La puissanceconsommée est de 62.5 mW sous 2.5 V d’alimentation.Le réseau présente un bruit de phase mesuré de -124.86dBc/Hz à 1 MHz de la porteuse pour une fréquence de5.78 GHz. L’intérêt d’un tel réseau consiste à contrôleractivement le déphasage des signaux produits parchaque OCT pour une utilisation dans un système deformation de faisceau