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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Measurement and modeling of passive surface mount devices on FR4 substrates

Koche, Rahulkumar Sadanand 01 January 2012 (has links)
Passive components like resistors, capacitors and inductors are used in every electronic system. These are the very basic components which affect the system performance at higher frequencies and it is necessary to understand and model the behavior of these components in a very accurate manner. This work focuses on utilizing Printed Circuit Board (PCB) test boards, or fixtures, made of FR4 for characterizing Surface Mount Device (SMD) components. Agilent's Advanced Design System (ADS) microwave circuit simulation software was used for designing the microstrip transmission lines as well as for generating the layout for manufacturing of the PCB. SMD resistors, capacitors and inductors were soldered into the fixture and then measured using the Vector Network Analyzer (VNA). The calibration kit was developed in ADS. The measured data were calibrated using the TRL (Thru-Reflect-Line) calibration algorithm. A calibration kit consisting of through, three transmission lines of various lengths, open and short was designed and manufactured. Calibration procedures were performed using Cascade Microtech's WinCal XE software. Based on our experience, TRL calibration did not perform to its full potential due to errors in the value of the characteristic impedance of microstrip transmission line. This impedance is ideally assumed to be 50 Ohm, but our lines had characteristic impedance of around 49 Ohm. Simple models for the resistors and capacitors were developed by our collaborators at the University of Zagreb and we developed the model for the inductors. We used ADS for simulations and comparison with the measured data. Extensive optimization of these models was done so as to fit the measured and modeled data. As the frequency goes above 4 GHz models and measurements don't match due to the limitations of the PCB material, the increasing effects of the parasitics and calibration artifacts. This work shows how and when we can use inexpensive FR4 PCB for the characterization of the passive SMD components in the low GHz frequency range. It also examines the range of operating frequency of SMD components, verifies the parameters extracted from the simple model and tests the TRL calibration algorithm.
32

Metallisation and structuring of low temperature Co-fired ceramic for micro and millimetre wave applications

Rathnayake-Arachchige, Dilshani January 2015 (has links)
The recent developments in Low Temperature Co-fired Ceramic (LTCC) as a substrate material enable it to be used in the micro and millimetre wave range providing low dissipation factors at high frequencies, good dielectric properties and a high degree of integration for further miniaturised devices. The most common metallisation method used in LTCC technology is screen printing with high cost noble metals such as silver and gold that are compatible with the high sintering temperatures (850°C). However, these techniques require high capital cost and maintenance cost. As the commercial world requires convenient and low cost process technologies for mass production, alternative metallisation methods should be considered. As a result, electroless copper plating of fired LTCC was mainly investigated in this research. The main goals of this project were to carry out electroless plating of fired LTCC with sufficient adhesion and to extend the process to metallise closed LTCC channel structures to manufacture Substrate Integrated Waveguide (SIW) components. The objectives were focused on electroless copper deposition on fired LTCC with improved adhesion. Electroless deposits on the Sn/Pd activated LTCC surface showed poor adhesion without any surface pre-treatments. Hence, chemical etching of fired LTCC was carried out using concentrated NaOH solution. NaOH pre-treatment of LTCC led to the formation of flake like structures on the LTCC surface. A number of surface and chemical analysis techniques and weight measurements were used to investigate the mechanism of the modification of the LTCC surface. The results showed that the flake like structures were dispersed in the LTCC material and a material model for the LTCC structure was proposed. SEM EDX elemental mapping showed that the flake like structure consisted of aluminium, calcium, boron and oxygen. Further experiments showed that both the concentration of NaOH and the immersion time affect the surface morphology and the roughness of fired LTCC. The measured Ra values were 0.6 μm for untreated LTCC and 1.1 μm for the LTCC sample treated with 4M NaOH for 270 minutes. Adhesion tests including peel test and scratch test were carried out to examine the adhesion strength of the deposited copper and both tests indicated that the NaOH pre-treatment led to an improvement, with the best results achieved for samples treated with 4M NaOH. A second aspect of the research focused on the selective metallisation of fired LTCC. Excimer laser machining was used to pattern a resist film laminated on the LTCC surface. This process also roughened the substrate and created channels that were characterised with respect to the laser operating parameters. After patterning the resist layer, samples were activated using Sn/Pd catalyst solution followed by the electroless copper deposition. Electroless copper was selectively deposited only on the patterned LTCC surface. Laser parameters clearly affected the copper plating rate. Even with a similar number of shots per area, the tracks machined with higher repetition rate showed relatively more machining depth as well as good plating conditions with low resistance values. The process was further implemented to realize a complete working circuit on fired LTCC. Passive components including a capacitor and an inductor were also fabricated on LTCC using the mask projection technique of the excimer laser system. This was successful for many designs, but when the separation between conductor lines dropped below 18 μm, electroless copper started to deposit on the areas between them. Finally, a method to deposit copper films on the internal walls of closed channel structures was developed. The method was first demonstrated by flowing electroless copper solutions through silane treated glass capillaries. A thin layer (approx. 60 nm) of electroless copper was deposited only on the internal walls of the glass capillaries. The flow rate of the electroless copper solution had to be maintained at a low level as the copper deposits tended to wash away with higher flow rates. The structures were tested for transmission losses and showed low (<10dB) transmission losses in the terahertz region of the electromagnetic spectrum. The process was further applied to deposit electroless copper on the internal walls of the LTCC closed channel structures to manufacture a LTCC Substrate Integrated Waveguide (SIW).
33

Etude et réalisation d'un circulateur hyperfréquence à nano particules magnétiques orientées dans la bande 40-60GHz / Study and fabrication of a microwave circulator with magnetic nanoparticles oriented in the 40-60 GHz range

Boyajian, Taline 27 September 2011 (has links)
Les composants passifs hyperfréquences deviennent de plus en plus commercialisés et employés dans les systèmes de télécommunications. La croissance technologique et l’augmentation de la demande des nouvelles applications requièrent de meilleures performances et de moindres coûts. Dans les applications sans fil et notamment dans les modules « émission/réception », les circulateurs sont utilisés pour l’émission et la réception des signaux simultanément à l’aide d’une seule antenne. Les couches magnétiques traditionnellement déposées et intégrées exigent une cristallisation à haute température ainsi que l’application d’un champ magnétique externe pour garder l’orientation des moments magnétiques. Cette orientation est cependant obtenue par des aimants lourds et volumineux. Devant ces limitations technologiques ainsi que la demande de miniaturisation, l’emploi de l’hexaferrite de baryum sous sa forme particulaire devrait permettre le développement de circulateurs auto-polarisés et miniaturisés à matériaux magnétiques composites. Les travaux présentés dans ce manuscrit ont pour objectif d’étudier et de réaliser un circulateur hyperfréquence à nano particules magnétiques orientées dans la bande 40-60 GHz. L’état de l’art expose les différentes topologies de circulateurs dont la topologie coplanaire est choisie pour notre application. L’étude analytique est basée sur les travaux de Bosma permettant de modéliser le circulateur triplaque. Les principales dimensions géométriques obtenues sont ensuite transposées vers la structure coplanaire en 3D à l’aide de l’outil de simulation HFSS. Devant les limitations de cet outil, différentes structures ont été étudiées et simulées numériquement pour présenter au mieux le matériau composite. Plusieurs séries de prototypes sont ensuite fabriquées à partir des structures optimisées en simulation numérique. Le matériau magnétique composite déposé a des épaisseurs de 40 et 100 μm. Les caractérisations hyperfréquences montrent la performance des dispositifs réalisés. Des pistes de recherche sont proposées pour l’amélioration des performances de nos prototypes / Microwave passive components become increasingly commercialized and used in telecommunications systems. Technological growth and the increased demand for new applications require higher performance and lower costs. In wireless applications, especially in "transceivers", circulators are used for transmitting and receiving signals simultaneously using a single antenna. Magnetic layers traditionally deposited and integrated require a high crystallization temperature and the application of an external magnetic field to keep the orientation of magnetic moments. This orientation is however obtained by heavy and bulky magnets. Given these technological limitations and the need to miniaturize, the use of barium hexaferrite particles envisages the development of self-biased and miniaturized circulators having magnetic composite materials. The ambition of this work is to study and to fabricate a microwave circulator with magnetic nanoparticles oriented in the 40 - 60 GHz range. The state of the art describes various topologies coplanar circulators from which the coplanar topology is chosen for our application. The analytical study is based on Bosma’s work to model the stripline circulator. The main geometric dimensions obtained are then transposed to the coplanar structure using the 3D simulation tool HFSS. Faced with this tool’s limitations, different structures were studied and simulated numerically to shape the best the composite material. Several series of prototypes are then manufactured. The magnetic composite material was deposited in layers having thicknesses of 40 and 100 μm. The microwave characterizations show the performance of the fabricated device. Research tracks are proposed to improve the performance of our prototypes
34

Microwave filters with high stop-band performance and low-loss hybrid developement

U-yen, Kongpop 17 November 2006 (has links)
This dissertation contains two significant investigations. One is the development of the broadband microwave bandpass filters with high out-of-band performance. The other is the development of low-loss hybrids. These researches are parts of the National Aeronautic and Space Administrator (NASA)s mission to explore the universe. The former is focused on the techniques used in microstrip line bandpass filter design that help achieving both low in-band insertion loss and high out-of-band attenuation level. Moreover, these filters achieve very broadband out-of-band attenuation bandwidth. These techniques are related to the improvement of stepped impedance resonators, coupling between resonators and effective methods to allocate transmission zeros to suppress filters out-of-band spurious responses. The later is focused on the techniques used in planar magic-T designs such that the developed magic-T obtains high isolation between port E (difference port) and port H (sum port). Moreover, it obtains low-loss and broadband characteristics. These techniques are related to the development of the low-loss broadband microstrip-toslotline (MS-to-SL transition and the magic-T with a highly symmetric structure. The theoretical analysis and experimental measurements have been performed. The experimental results of both the filter and magic-T researches show significant improvement over their prior state-of-the-art designs by number of magnitude. The designs also reduce fabrication complexity.
35

Range finding in passive wireless sensor networks using power-optimized waveforms

Trotter, Matthew 14 November 2011 (has links)
Passive wireless sensor networks (WSNs) are quickly becoming popular for many applications such as article tracking, position location, temperature sensing, and passive data storage. Passive tags and sensors are unique in that they collect their electrical energy by harvesting it from the ambient environment. Tags with charge pumps collect their energy from the signal they receive from the transmitting source. The efficiency of converting the received signal to DC power is greatly enhanced using a power-optimized waveform (POW). Measurements in the first part of this dissertation show that a POW can provide efficiency gains of up to 12 dB compared to a sine-wave input. Tracking the real-time location of these passive tags is a specialized feature used in some applications such as animal tracking. A passive WSN that uses POWs for the improvement of energy-harvesting may also estimate the range to a tag by measuring the time delay of propagation from the transmitter to the tag and back to the transmitter. The maximum-likelihood (ML) estimator is used for estimating this time delay, which simplifies to taking the cross-correlation of the received signal with the transmitted signal. This research characterizes key aspects of performing range estimations in passive WSNs using POWs. The shape of the POW has a directly-measurable effect on ranging performance. Measurements and simulations show that the RMS bandwidth of the waveform has an inversely proportional relationship to the uncertainty of a range measurement. The clutter of an environment greatly affects the uncertainty and bias exhibited by a range estimator. Random frequency-selective environments with heavy clutter are shown to produce estimation uncertainties more than 20 dB higher than the theoretical lower bound. Estimation in random frequency-flat environments is well-behaved and fits the theory quite nicely. Nonlinear circuits such as the charge pump distort the POW during reflection, which biases the range estimations. This research derives an empirical model for predicting the estimation bias for Dickson charge pumps and verifies it with simulations and measurements.
36

Évaluation d’un module électro-optique hybride combinant la photonique sur silicium et sur verre pour des applications de multiplexage en longueur d’onde (WDM) / Assessment of an hybrid electro-optic module combining silicon and ions exchange glass photonics in order to address high speed Wavelength Division Multiplexing applications (WDM)

Ayi-Yovo, Folly Eli 05 April 2017 (has links)
La demande sans cesse croissante des besoins des télécommunications a mis en relief les limites intrinsèques de l’électronique. La photonique s’est révélée comme une solution appropriée à ses limitations. STMicroelectronics a développé une plateforme photonique sur silicium dénommée PIC25G permettant une transmission monocanale à 25 Gb/s. Cependant, l’augmentation du débit avec du multiplexage en longueur d’onde (WDM) se heurte à certaines contraintes. La solution suggérée repose sur une approche hybride intégrant la photonique sur silicium et sur verre par échange d’ions développée au laboratoire IMEP LaHC. La solution consiste en un interposeur verre sur lequel est assemblée une puce photonique sur silicium. Les études ont d’abord porté sur les composants de la puce silicium en particulier sur l’optimisation des coupleurs à réseau et les multiplexeurs à base d’interféromètres de Mach Zehnder cascadés. Ensuite, les composants passifs optiques et électriques de l’interposeur verre ont aussi été étudiés et réalisés. La faisabilité d’un couplage optique entre la puce silicium et l’interposeur a été démontrée. Enfin, les structures de tests nécessaires à la validation de la solution proposée ont été étudiées. Ces structures de tests ont permis de transmettre des signaux radiofréquences jusqu’à 40 GHz entre la puce silicium et l’interposeur verre. Une nouvelle approche de fabrication des guides d’onde optiques de l’interposeur a été suggérée et réalisée afin de répondre aux problèmes du procédé de fabrication. A terme, elle permettra d’avoir un module électro-optique pour des applications haut-débit. / The ever-increasing demand for telecommunications needs has highlighted the intrinsic limitations of electronics. Photonics has proven to be a suitable solution to its limitations. STMicroelectronics has developed a silicon photonic platform called PIC25G that allows single-channel transmission at 25 Gb/s. The data rate increase with wavelength division multiplexing (WDM) encounter some constraints. The proposed solution is based on a hybrid approach integrating silicon photonics and glass ions exchanged photonics developed at the IMEP-LaHC laboratory. The solution consists of a glass interposer on which a silicon photonics chip is assembled. First, the studies focused on the components of the silicon chip especially on the optimization of grating couplers and (de)-multiplexers based on cascaded Mach Zehnder interferometers. Then, the optical and electrical passive components of the glass interposer were studied and realized. The feasibility of an optical coupling between the silicon chip and the glass interposer has been demonstrated. Finally, the test structures needed to validate the proposed solution were studied. These test structures allowed to transmit radiofrequency signals up to 40 GHz between the silicon chip and the glass interposer. A new approach to realize the optical waveguides of the interposer has been suggested and carried out in order to address the fabrication issues. Ultimately, this approach will provide an electro-optical module for high-speed applications.
37

Etude de l’empilement de couches minces de cuivre sur alumine : applications à la réalisation de composants passifs haute température / Study of thin copper layer / alumina stack : applications to realize passive components operating on high temperature.

Doumit, Nicole 26 May 2015 (has links)
Ce travail de thèse consiste à étudier l’empilement de couche mince de cuivre sur un substrat d’alumine afin de réaliser des composants passifs fonctionnant à haute température. Une étude des couches minces de cuivre a été tout d’abord menée par simulation à l’aide du logiciel COMSOL Multiphysics et expérimentalement à l’aide de bancs de caractérisation spécifiques. Cette étude a permis de mettre en évidence une augmentation des contraintes équivalentes de Von Mises stress avec la température et avec l'épaisseur de cuivre. Les simulations montrent également une relaxation des contraintes résiduelles après un recuit d’une heure de la couche de cuivre. Les résultats expérimentaux montrent une augmentation de l’adhérence avec la température et l’absence de tout indice de fissures. D’autre part, des études électriques sur des composants intégrés ont été effectuées: soit après recuit des composants soit en cyclage thermique (25-200°C). Ces mesures ont permis de mettre en évidence une stabilité de la valeur de l’inductance quel que soit le type de traitement thermique effectué. La résistance augmente avec la température et retrouve sa valeur initiale après un cyclage thermique. Ce qui n’est pas le cas après un recuit ; la résistance augmente mais ne retrouve plus sa valeur initiale après refroidissement. Ainsi, ce travail a permis de conclure que les composants testés restent fonctionnels à haute température sans aucune détérioration / This thesis is a study of copper thin film on an alumina substrate in order to realize passive components operating at high temperature. A study of copper thin films was made by simulation using COMSOL Multiphysics software and experimentally using specific characterization benches. This study highlighted an increase of Von Mises equivalent stresses with temperature and with copper thickness. Simulations also show a relaxation of residual stresses after one hour of annealing. Experimental results show an increase of adhesion in function of temperature and an absence of cracks. On the other hand, electrical studies for integrated components were performed either after annealing or in thermal cycling (25-200°C). These measures highlighted inductance stability regardless of heat treatment type. The resistance increases with temperature and returns, after thermal cycling, to its initial value. This is not the case after annealing; the resistance increases but cannot return to its initial value after cooling. Thus, this work has concluded that tested components remain functional at high temperature without any deterioration
38

Étude multicritère pour l'enfouissement partiel ou total de convertisseurs d'électronique de puissance dans un circuit imprimé / Multi-criteria study for partial or complete Printed Circuit Board embedding of power electronic converters

Pascal, Yoann 22 October 2019 (has links)
Les travaux présentés dans ce manuscrit traitent de l’enfouissement dans un circuit imprimé de convertisseurs de puissance, paradigme visant l’insertion de composants électroniques au sein du circuit imprimé.Une structure simple et économique de composant inductif enfoui, pouvant être employé comme inductance, coupleur, ou résonateur monolithique, est tout d’abord décrite. Un modèle analytique complet est développé. Des prototypes sont réalisés, validant le modèle et démontrant l’intérêt de la topologie.L’agencement des composants de puissance constituant une cellule de commutation est ensuite étudié. En particulier, un modèle analytique permettant une compréhension intuitive des mécanismes oscillatoires dans le cadre de l’emploi de transistors rapides est décrit.Une technique de reprise de contact de face avant pour puce enfouie, basée sur un morceau de mousse pressée, est proposée. Une étude préliminaire, à forte composante expérimentale, est présentée. Elle démontre que certains prototypes enfouis présentent des caractéristiques électriques et une fiabilité similaires à celles obtenus avec des fils de bonding.Enfin, les résultats de l’étude sur l’agencement des composants d’une cellule de commutation sont appliqués pour concevoir et réaliser un hacheur basé sur des transistors SiC connectés par mousse pressée. La structure délivre 3 kW sous 600 V en continu, démontrant la viabilité du procédé de reprise de contact proposé. / This thesis deals with Printed-Circuit Board (PCB) embedding of power converters, paradigm according to which electronic components are placed within the substrate itself.First, a simple and economical structure of inductive component, which can be used either as an inductor, a coupler, or a monolithic resonator, is described. A comprehensive analytical model is developed. Prototypes are manufactured, validating the analytical model and highlighting the value of the topology.The arrangement of the power components of a switching cell is then studied. In particular, an analytical model offering an intuitive understanding of the oscillation mechanisms in cells using fast transistors is proposed.A simple and economical top-side connection technic for PCB-embedded power dies using a pressed piece of metal foam is described. A preliminary study, with strong experimental component, is proposed. It shows that the embedded prototypes have electrical performances and a reliability close to that of wire-bonded dies.Finally, the results from the study on the arrangement of the components of a switching cell are used to design and manufacture a chopper based on SiC transistors connected using a piece of pressed metal foam. This chopper proved to be able to continuously deliver 3 kW under 600 V to a load, thereby validating the proposed top-side connection technic.
39

Ultra compact multi-standard low-noise amplifiers in 28 nm CMOS with inductive peaking

Sobotta, Elena, Belfiore, Guido, Ellinger, Frank 04 June 2020 (has links)
This work presents the design of two compact multi-standard low-noise amplifier (LNA) in a 28 nm low-power bulk CMOS process. The transistor parameters were optimized by the Gₘ/ID method taking into account the parasitics and the behavior of highly scaled transistors. To cover the industrial science medical (ISM)-bands around 2.4 and 5.8 GHz, the WLAN band as well as the Kᵤ band a bandwidth enhancement is required. Two versions of LNAs, one with vertical inductors and one with active inductors, are implemented and verified by measurements. The noise figure (NF) exhibits 4.2 dB for the LNA with active inductors and 3.5 dB for the LNA with vertical inductors. The voltage gain reaches 12.8 and 13.4 dB, respectively, with a 3 dB-bandwidth of 20 GHz. Both input referred 1-dB-compression points are higher than 212 dBm making the chips attractive for communication standards with high linearity requirements. The chips consume 53 mW DC power and the LNA with active inductors occupies a core area of only 0.0018 mm², whereas the version with vertical inductors requires 0.021 mm².
40

Posouzení možností regulace napětí v distribučních sítích nn / Evaluation of possibilities for voltage control in a LV distribution network

Bolgár, Robert January 2013 (has links)
This paper deals with possible ways of voltage regulation. Theoretical part includes a search of published methods and the available voltage regulators. Acquired theoretical knowledge has been applied in the development of mathematical models of two selected controllers applied to the testing network. The result of this work is a summary of the outcomes of dynamic simulations with two selected regulators at various locations in testing network. Comparing the results of dynamic simulation for two selected states was chosen the most appropriate regulator and its optimal location in testing network.

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