Dissertations / Theses on the topic 'Time-domain Circuits'
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Haddadin, Baker. "Time domain space mapping optimization of digital interconnect circuits." Thesis, McGill University, 2009. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=116004.
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Microwave circuit design including the design of Interconnect circuits are proving to be a very hard and complex process where the use of CAD tools is becoming more essential to the reduction in design time and in providing more accurate results. Space mapping methods, the relatively new and very efficient way of optimization which are used in microwave filters and structures will be investigated in this thesis and applied to the time domain optimization of digital interconnects. The main advantage is that the optimization is driven using simpler models called coarse models that would approximate the more complex fine model of the real system, which provide a better insight to the problem and at the same time reduce the optimization time. The results are always mapped back to the real system and a relation/mapping is found between both systems which would help the convergence time. In this thesis, we study the optimization of interconnects where we build certain practical error functions to evaluate performance in the time domain. The space mapping method is formulated to avoid problems found in the original formulation where we apply some necessary modifications to the Trust Region Aggressive Space Mapping TRASM for it to be applicable to the design process in time domain. This new method modified TRASM or MTRASM is then evaluated and tested on multiple circuits with different configuration and the results are compared to the results obtained from TRASM.
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Choo, Boy Lee. "Microwave GaAs MESFET circuit design using time-domain simulation." Thesis, Queen's University Belfast, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356890.
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Chan, Antonio. "Circuits for time and frequency domain characterization of jitter." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=29532.
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Jitter characterization has become significantly more important for systems running at multi-gigahertz data rates. Time and frequency domain characterization of jitter is thus a crucial element for system specification testing. Time domain jitter measurement on a data signal with sub-gate timing resolution can be achieved using two delay chains feeding into the clock and data lines of a series of D-latches known as a Vernier Delay Line (VDL). An important drawback to the VDL structure is that its measurement accuracy depends on the matching of the various delay elements. Although careful layout techniques can help to minimize these mismatches, it cannot eliminate them completely. As well, due to the nature of the design, a relatively large silicon area is required for silicon implementation. In this work, a novel technique is developed which reduces the silicon area requirements by two orders of magnitude, as well enables the measurement device to be synthesized from a register transfer level (RTL) description. A custom IC was designed and fabricated in a 0.18 mum CMOS process as a first proof of concept. The design requires a silicon area of 0.12 mm2 and measured results indicate a timing resolution of 19 ps. The synthesizable nature of the design is demonstrated using a FPGA implementation. In addition, another custom IC was designed and fabricated in a 0.35 mum CMOS process as a frequency characterization circuit to process and extract information from the data obtained from the VDL. This design occupies a silicon area of 1.83 mm2. As test time is an important consideration for a production test, an extension to this component-invariant VDL technique is provided that reduces test time at the expense of more hardware. Finally, a method for obtaining the frequency domain characteristics of the jitter using the VDL will also be given.
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Toner, Brendan. "Nonlinear time domain characterisation of sub-micron RF MOS transistors." Thesis, Queen's University Belfast, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269140.
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Pannala, Sreemala. "Development of time domain characterization methods for packaging structures." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/16470.
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CHAKRABORTY, RITOCHIT. "SYMBOLIC TIME DOMAIN BEHAVIOR AND PERFORMANCE ANALYSIS OF LINEAR ANALOG CIRCUITS." University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1145990101.
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Cocchini, Matteo. "Via transition modeling and charge replenishment of the power delivery network in multilayer PCBs." Diss., Rolla, Mo. : Missouri University of Science and Technology, 2008. http://scholarsmine.mst.edu/thesis/pdf/Cocchini_09007dcc805051ee.pdf.
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Thesis (M.S.)--Missouri University of Science and Technology, 2008.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed May 27, 2008) Includes bibliographical references.
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Chen, Qiang. "Finite-difference time-domain method for combined large signal circuit and electromagnetic field analysis." Thesis, Queen's University Belfast, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.337664.
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Yang, Chuanyi. "Time domain and parallel distributed integral equation techniques for full-wave microelectronics simulation /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/5926.
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Li, Zhao. "SPICE-accurate iterative methods for efficient time-domain simulation of VLSI circuits with strong parasitic couplings /." Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/5830.
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Choi, Jinseong. "Modeling of power supply noise in large chips using the finite difference time domain method." Diss., Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/14977.
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Kitchen, Alistair J. "CMOS digital pixel sensor array with time domain analogue to digital conversion." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2004. https://ro.ecu.edu.au/theses/765.
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This thesis presents a digital pixel sensor array, which is the first stage of an ongoing project to produce a CMOS image sensor with on-chip image processing. The analogue to digital conversion is performed at the pixel level, with the result stored in pixel memory. This architecture allows fast, reliable access to the image data and simplifies the integration of the image array and the processing logic. Each pixel contains a photodiode sensor, a comparator, memory and addressing logic. The photodiode sensor operates in integrating mode, where the photodiode junction capacitance is first charged to an initial voltage, and then discharged by the photodiode leakage current, which is comprised mainly of optically generated carriers. The analogue to digital conversion is performed by measuring the time taken for the photodiode cathode voltage to fall from its initial voltage, to the comparator reference voltage. This triggers the 8-bit pixel memory, which stores a data value representative of the time. The trigger signal also resets the photodiode, which conserves the charge stored in the junction capacitance, and also prevents blooming. An on-chip control circuit generates the digital data that is distributed globally to the array. The control circuit compensates for the inverse relationship between the integration time and the photocurrent by adjusting the data clock timing. The period of the data clock is increased at the same rate as the integration time, resulting in a linear relationship between the digital data and the photocurrent. The design is realised as a 64 x 64 pixel array, manufactured in O.35µm 3.3 V CMOS technology. Each pixel occupies an area of 45µm x 45µm with a 12.3% fill factor, and the entire pixel array and control circuit measures 3.7mm x 3.9mm. Experimental results confirm the operation of the digital pixel, and the linearising control circuit. The digital pixel has a dynamic range of 85dB, and can be adapted to different lighting conditions by varying a single clock frequency. The data captured by the array can be randomly accessed, and is read from the array nondestructivcly.
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Schuster, Christian. "Simulation, analysis, and parameter extraction of electronic components and circuits using the finite difference time domain method /." Zürich, 1999. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=13522.
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Shorthouse, David Brian. "The CAD and analysis of passive monolithic microwave integrated circuits by the finite difference time domain technique." Thesis, University of Bristol, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362984.
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Bushyager, Nathan Adam. "Development of models for electrostatically-actuated RF-MEMS interdigitated capacitors using novel FDTD and MRTD approaches." Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/15484.
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Lee, Anyu 1963. "Transient analysis of interconnections using spectral method." Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276750.
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The present paper introduces one very efficient and flexible time-domain analysis technique to predict the kinds of reflections and crosstalk. Numerical results show that this technique is indeed efficient and accurate in the transient analysis of a general multiple line system. Furthermore, this algorithm can be eventually coded in a form of a subroutine compatible with any standard CAD program, such as SPICE.
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Gao, Xuejun. "Application of Finite-Difference Time-Domain Method To Calculate Power Converter Electromagnetic Fields." Clermont-Ferrand 2, 2003. http://www.theses.fr/2003CLF21425.
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Dans cette thèse, nous avons d'abord calculé les paramètres linéiques des circuits imprimés en utilisant la méthode de moments, les résultats sont similaires à ceux obtenus par le logiciel FD2D. Ensuite, nous avons appliqué la théorie des lignes en temporel et analysé les tensions induites pour différentes géométries et comparé les résultats à ceux obtenus par le logiciel PSPICE. En seconde partie, nous avons présenté la méthode des différences finies en 3D, comparé plusieurs techniques de limites absorbantes et discuté leurs performances sur les convertisseurs de puissance en matière de temps de calcul et de précision ; les résultats présentés correspondent au rayonnement E et H d'un convertisseur DC-Dc pour différentes charges. En troisième partie, nous avons établi des relations empiriques entre la fréquence de résonance et les paramètres physiques et géométriques du circuit imprimé, les résultats sont déterminés dans le domaine fréquentiel et comparés aux résultats issus de la méthode des moments. Par ailleurs, les champs électromagnétiques en dehors du domaine de calcul sont déterminés en utilisant la transformation champ proche-champ lointain. En conclusion, l'effet du plan de masse ainsi que de la présence d'un sol réel sont pris en considération
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Zhou, Dong Huang Wei-Ping. "Advanced finite-difference time-domain techniques for simulation of optical devices with complex material properties and geometric configurations /." *McMaster only, 2005.
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Mao, Jifeng. "Modeling of simultaneous switching noise in on-chip and package power distribution networks using conformal mapping, finite difference time domain and cavity resonator methods." Diss., Available online, Georgia Institute of Technology, 2005, 2004. http://etd.gatech.edu/theses/available/etd-10062004-125025/.
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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2005.Madhavan Swaminathan, Committee Chair ; Sung Kyu Lim, Committee Member ; Abhijit Chatterjee, Committee Member ; David C. Keezer, Committee Member ; C. P. Wong, Committee Member. Vita. Includes bibliographical references.
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Jeong, Jaehoon. "Analytical time domain electromagnetic field propagators and closed-form solutions for transmission lines." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1105.
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Ha, Myunghyun. "EM simulation using the Laguerre-FDTD scheme for multiscale 3-D interconnections." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42850.
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As the current electronic trend is toward integrating multiple functions in a single electronic device, there is a clear need for increasing integration density which is becoming more emphasized than in the past. To meet the industrial need and realize the new system-integration law [1], three-dimensional (3-D) integration is becoming necessary. 3-D integration of multiple functional IC chip/package modules requires co-simulation of the chip and the package to evaluate the performance of the system accurately. Due to large scale differences in the physical dimensions of chip-package structures, the chip-package co-simulation in time-domain using the conventional FDTD scheme is challenging because of Courant-Friedrich-Levy (CFL) condition that limits the time step. Laguerre-FDTD has been proposed to overcome the limitations on the time step. To enhance performance and applicability, SLeEC methodology [2] has been proposed based on the Laguerre-FDTD method. However, the SLeEC method still has limitations to solve practical 3-D integration problems.
This dissertation proposes further improvements of the Laguerre-FDTD and SLeEC method to address practical problems in 3-D interconnects and 3-D integration. A method that increases the accuracy in the conversion of the solutions from Laguerre-domain to time-domain is demonstrated. A methodology that enables the Laguerre-FDTD simulation for any length of time, which was challenging in prior work, is proposed. Therefore, the analysis of the low-frequency response can be performed from the time-domain simulation for a long time period. An efficient method to analyze frequency-domain response using time-domain simulations is introduced. Finally, to model practical structures, it is crucial to model dispersive materials. A Laguerre-FDTD formulation for frequency-dependent dispersive materials is derived in this dissertation and has been implemented.
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Park, Shinwoong. "Reconfigurable Discrete-time Analog FIR filters for Wideband Analog Signal Processing." Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/99794.
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Demand for data communication capacity is rapidly increasing with more and more number of users and higher bandwidth services. As a result, a critical research issue is the implementation of wideband and flexible signal processing in communication and sensing applications. Although software defined radio (SDR) is a possible solution, it may not be practical due to the excessive requirements for analog-to-digital converter (ADCs) and digital filters for wideband signals. In this environment, discrete-time (DT) domain circuits are gaining attention in various architectures such as N-path filters, sampling mixers, and analog FIR/IIR/FFT filters. DT analog signal processing (DT-ASP) ahead of an ADC considerably relaxes the ADC requirements by flexible filtering, offers the potential for higher dynamic range performance, and provides robustness in the presence of digital CMOS scaling.
The primary work presented in this dissertation is the design of wideband analog finite impulse response (AFIR) filters. Analog FIR filters have been used as low pass filters for out-of-band rejection in narrow-band applications. However, this work seeks to develop AFIR filters suitable for wideband applications, extending its possible applications. To achieve these performance goals, capacitive digital to analog converters (CDACs) have been introduced for the first time as wideband analog coefficient multipliers, which has led to high linearity analog multiplication with coefficient selection at the DAC resolution. A prototype 4th order DT FIR filter has been implemented in 32nm SOI CMOS technology and has achieved low-pass, band-pass, and high-pass filter (LPF, BPF and HPF) transfer functions corresponding to the programmed coefficient sets with IIP3>11dBm linearity and less than 2 mW/tap of power consumption. The AFIR filter is also utilized to demonstrate a proof-of-concept FIR-based beamforming. The beamforming network consisting of 4 antenna element inputs followed by AFIR filters was implemented with PCB modules with the previously fabricated AFIR filter chip. Behavioral simulations are used to verify the beamforming function with given coefficient sets. Based on the developed AFIR filter modules, FIR-based beamforming was demonstrated with measurement results matching well with the simulations.
Further work presented is the design and optimization of multi-section CDAC (MS-CDAC) structures. The proposed MS-CDAC approach provides wide range of options to optimize the tradeoff between kT/C noise, linearity versus switching energy, speed and area. When the optimization approach is applied to a proof-of-concept 10-bit CDAC design, the selected MS-CDAC structure reduces total capacitance and switching energy by 97% and 98%, respectively for given linearity and noise limitations. The proposed MS-CDAC structures are applicable in both DT-ASP coefficient multiplier and SAR-ADC applications.PHD
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Smith, Austin Gregory. "Characterization and Quantification of Early Stages for Organic Coatings Applied on AA2024/AA7075 by Correlating Frequency Domain Approach in Real Time." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1399125698.
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Reinke, Charles M. "Design, simulation, and characterization toolset for nano-scale photonic crystal devices." Diss., Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/33932.
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The objective of this research is to present a set of powerful simulation, design,
and characterization tools suitable for studying novel nanophotonic devices. The
simulation tools include a three-dimensional finite-difference time-domain code adapted
for parallel computing that allows for a wide range of simulation conditions and material
properties to be studied, as well as a semi-analytical Green's function-based complex
mode technique for studying loss in photonic crystal waveguides. The design tools
consist of multifunctional photonic crystal-based template that has been simulated with
nonlinear effects and measured experimentally, and planar slab waveguide structure that
provides highly efficient second harmonic generation is a chip-scale device suitable for
photonic integrated circuit applications. The characterization tool is composed of a
phase-sensitive measurement system using a lock-in amplifier and high-precision optical
stages, suitable for probing the optical characteristics of nanoscale devices. The high
signal-to-noise ratio and phase shift data provided by the lock-in amplifier allow for
accurate transmission measurements as well as a phase spectrum that contains
information about the propagation behavior of the device beyond what is provided by the
amplitude spectrum alone.
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Ogunsola, Oluwafemi Olusegun. "Prospects for Mirror-Enabled Polymer Pillar I/O Optical Interconnects for Gigascale Integration." Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14067.
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Digital systems have derived performance benefits due to the scaling down of CMOS microprocessor feature sizes towards packing billions of transistors on a chip, or gigascale integration (GSI). This has placed immense bandwidth demands on chip-to-chip and chip-to-board interconnects. The present-day electrical interconnect may limit bandwidth as transmission rates grow. As such, optical interconnects have been proposed as a potential solution. A critical requirement for enabling chip-to-chip and chip-to-board optical interconnection is out-of-plane coupling for directing light between a chip and the board. Any solution for this problem must be compatible with conventional packaging and assembly requirements. This research addresses the prospects for integrating waveguides with mirrors and polymer pillar optical I/O interconnects to provide such a compatible, out-of-plane, chip-to-board packaging solution through the design, analysis, fabrication, and testing of its constituent parts and their ultimate integration.
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Takhedmit, Hakim. "Modélisation et conception de circuits de réception complexes pour la transmission d'énergie sans fil à 2.45 GHz." Phd thesis, Ecole Centrale de Lyon, 2010. http://tel.archives-ouvertes.fr/tel-00564596.
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Les travaux présentés dans ce mémoire s'inscrivent dans la thématique de la transmission d'énergie sans fil, appliquée à l'alimentation à distance de capteurs, de réseaux de capteurs et d'actionneurs à faible consommation. Cette étude porte sur la conception,l'optimisation, la réalisation et la mesure de circuits Rectennas (Rectifying antennas)compacts, à faible coût et à haut rendement de conversion RF-DC.Un outil d'analyse globale, basé sur la méthode des Différences Finies dans le Domaine Temporel (FDTD), a été développé et utilisé pour prédire avec précision la sortie DC des rectennas étudiées. Les résultats numériques obtenus se sont avérés plus précis et plus complets que ceux de simulations à base d'outils commerciaux. La diode Schottky a été rigoureusement modélisée, en tenant compte de ses éléments parasites et de son boîtier SOT23, et introduite dans le calcul itératif FDTD.Trois rectennas innovantes, en technologie micro-ruban, ont été développées,optimisées et caractérisées expérimentalement. Elles fonctionnent à 2.45 GHz et elles ne contiennent ni filtre d'entrée HF ni vias de retour à la masse. Des rendements supérieurs à 80% ont pu être mesurés avec une densité surfacique de puissance de l'ordre de 0.21 mW/cm²(E = 28 V/m). Une tension DC de 3.1 V a été mesurée aux bornes d'une charge optimale de1.05 k_, lorsque le niveau du champ électrique est égal à 34 V/m (0.31 mW/cm²).Des réseaux de rectennas connectées en série et en parallèle ont été développés. Les tensions et les puissances DC ont été doublées et quadruplées à l'aide de deux et de quatre éléments, respectivement.
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Lalgudi, Subramanian N. "Transient simulation of power-supply noise in irregular on-chip power distribution networks using latency insertion method, and causal transient simulation of interconnects characterized by band-limited data and terminated by arbitrary terminations." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22561.
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Kalialakis, Christos. "Finite difference time domain analysis of microstrip antenna-circuit modules." Thesis, University of Birmingham, 1999. http://etheses.bham.ac.uk//id/eprint/65/.
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Compact microstrip antenna-circuit modules, which could be used as front-ends for future wireless systems applications, require electromagnetic modelling due to the close interaction of the circuit with the antenna. Spectrum crowding and EMC/EMI issues call for modelling of the radiation of such modules. Coupling through fringing fields and the nonlinearities of active devices must be addressed. In this work, the FDTD method was used because it can provide the framework for inclusion of circuit elements in a full wave calculation. A software tool was developed and validated based on this method. The modules studied were chosen due to their compactness and their merit as system components. A module with simultaneous transmit-receive operation integrating an active circulator (using amplifiers in a ring-like arrangement) and a quarter wavelength antenna was analysed. Coupling effects were identified and their impact on the radiation patterns was shown. Electronically tuneable microstrip patch antennas using varactor diodes were also studied. Tuning range and harmonic radiation were demonstrated. Single and dual device Gunn oscillator antennas were analysed and their radiation patterns were calculated for the first time. All of our results were in agreement with experimental findings.
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Lau, P. H. "Computer aided design of microelectronic systems in the time domain." Thesis, University of Sunderland, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.234044.
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Vardanyan, Konstantin. "A Low Cost Time Domain Reflectometry Circuit for printed Electronic Applications." Thesis, KTH, Material- och nanofysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-143197.
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Liu, Yang. "Study of electronic circuit-radiated near-field emissions in time-domain." Rouen, 2012. http://www.theses.fr/2012ROUES037.
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The object of this PhD thesis is the investigation on the radiated near-field emission in the time-domain in order to predict the EMC compliances on the low- and high-frequency electronic/electrical systems. First, chapter 1 synthesizes the existing methods and techniques dedicated to the NF emission modelling and measurement in the literature, in both frequency- and time-domain. In chapter 2, a time-frequency computational methodology is proposed which allows the extraction of TD NF maps from the frequency-dependent field data for any type of complex transient excitation. Then, in chapter 3, by considering the TF calculation method introduced previously, time-domain NF extraction methods were established based on the Plane Wave Spectrum theory combined with the fundamental plane wave properties as orthogonality, wave translation property and Maxwell-Ampere relation. Also, a TD transposition of the inverse method for NF emission modelling with elementary EM dipole arrays acting as equivalent radiating sources for the EMC emission prediction is devoted in chapter 4. All proposed approaches have been validated by simulations and measurements using passive RF/Microwave circuits. As expected, very good validation results have been found for each method introduced in this PhD thesis. Moreover, in the final chapter, a fully time-domain near-field measurement technique is proposed and described in details including the calibration method. In order to verify the efficiency of the test bench, experimentations were performed with different ultra-short excitation signals having ns-time durationL’objet de cette thèse est l’étude de l’émission champ proche temporel rayonnée destinée pour les applications CEM. Tout d’abord, le chapitre 1 présente la synthèse des méthodes de la modélisation fréquentielles et temporelles et de la mesure de l’émission rayonnée en champ proche existantes dans la littérature. Dans le chapitre 2, une méthodologie fréquentio-temporelle innovante permettant l’analyse des données champ proche en temps et en fréquence est proposée. Cette méthode de calcul permet d'extraire les cartes de champ temporel à partir des données fréquentielles pour des excitations complexes transitoires quelconques. En tenant compte de l’approche FT présentée précédemment, des méthodes d’extraction et de traitement champ proche temporel comme ont été établies dans le chapitre 3. Elles ont été développées à partir de la théorie du spectre d’onde plane en combinant avec les propriétés fondamentales des ondes planes comme l’orthogonalité, la propriété de translation d’onde plane et la relation de Maxwell-Ampère. Ensuite, une extension de la méthode inverse de modélisation des émissions champ proche à base des réseaux de dipôles EM élémentaires vers le domaine temporel fait l’objet du chapitre 4. Toutes les approches proposées ont été validées par des simulations et des mesures avec les circuits passives RF / micro-ondes. Comme prévu, les très bons résultats ont été trouvés pour chaque méthode présentée dans cette thèse. Par ailleurs, dans le dernier chapitre, une technique de mesure du champ proche totalement temporel est proposée et décrite en détail, y compris la technique de calibration. Afin de vérifier l'efficacité du banc de test, les expérimentations ont été réalisées avec différents signaux d’excitation ultra-courte ayant ns-temps de durée
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Charlamov, Jevgenij. "Time domain optical reflectometer systems investigation." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2014. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2013~D_20140227_140438-77567.
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The dissertation investigates the optical time domain reflectometer (OTDR) systems. The main object of research is an optical receiver for OTDR. The aim of the work is to create an optical receiver design method-ology to achieve optimal dynamic range of the system for a given band-width, design and investigate integrated fully differential variable gain tran-simpedance amplifier for OTDR optical receiver.
Main tasks solved in this work are: perform analysis of OTDR struc-tures, main specifications and suggest possible improvement approaches; analyze main optical receiver noise sources and noise minimization and create generalized noise model; create optical receiver for an OTDR design methodology, that allow calculating avalanche photodiode multiplication factor, transimpedance amplifier feedback resistance and voltage amplifier input transistor dimensions that achieves optimal OTDR dynamic range; design and perform simulations of transimpedance amplifier integrated cir-cuit using AMS 0.35 µm CMOS technology and calculate optical receiver parameters in 0.1–100 MHz range of bandwidths
The dissertation consists of four parts including Introduction, 4 chap-ters, Conclusions, References and 1 Annex.
The introduction reveals the investigated problem, importance of the thesis and the object of research. It also describes the purpose and tasks, research methodology, scientific novelty, the practical significance of re-sults examined in the paper and defended statements. The... [to full text]Disertacijoje nagrinėjamos laiko srities optinės reflektometrinės (OTDR) sistemos. Pagrindinis tyrimo objektas yra OTDR įėjimo pakopa – optinis imtuvas (OI). Disertacijos tikslas – sukurti OI projektavimo metodiką, lei-džiančią pasiekti optimalų dinaminį diapazoną, suprojektuoti ir ištirti integ-rinį diferencinį pereinamos varžos stiprintuvą (PVS) su kintamu stiprinimo koeficientu. Darbe sprendžiami šie uždaviniai: atliekama OTDR ir jų pagrindinių charakteristikų analizė ir formuluojamos tobulinimo kryptys; analizuojami pagrindiniai optinio imtuvo triukšmų šaltiniai, jų mažinimo galimybės ir su-daromas apibendrintas optinio imtuvo triukšmų modelis; sukuriama OI pro-jektavimo metodika, leidžianti apskaičiuoti griūtinio fotodiodo dauginimo faktorių, pereinamosios varžos stiprintuvo grįžtamojo ryšio varžą ir įėjimo tranzistoriaus fizinius matmenis, kuriems esant gaunamas optimalus dina-minis diapazonas; projektuojamas optinio imtuvo maketas iš diskrečiųjų elementų ir tiriami jo parametrai; atliekamas integrinio PVS projektavimas ir modeliavimas, taikant 0,35 µm KMOP technologiją bei optinio imtuvo pa-rametrų skaičiavimas 0,1–100 MHz dažnių juostų diapazone. Disertaciją sudaro įvadas ir keturi skyriai. Pabaigoje pateikiami naudo-tos literatūros ir autoriaus publikacijų disertacijos tema sąrašai ir 1 priedas. Įvadiniame skyriuje aptariama: tiriamoji problema, darbo aktualumas, aprašomas tyrimų objektas, suformuluotas darbo tikslas bei uždaviniai, ap-rašoma tyrimų metodika... [toliau žr. visą tekstą]
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Visan, Silviu. "Simulation électromagnétique 3D basée sur la méthode des différences finies dans le domaine temporel : application à l'étude de structures planaires utilisées dans les circuits intégrés monolithiques microondes et millimétriques." Grenoble INPG, 1994. http://www.theses.fr/1994INPG0014.
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Ce travail de these a permis la mise au point et l'implementation d'une methode de simulation electromagnetique tridimensionnelle basee sur les differences finies dans le domaine temporel (fdtd - finite difference time domain). Le logiciel qui a ete realise sert a caracteriser des structures planaires, notamment celles utilisees dans les circuits integres monolithiques microondes (mmic - microwave monolithic integrated circuits). Le chapitre 1 presente le contexte de l'etude. Dans le chapitre 2 nous presentons en detail la methode qui est a la base de nos simulations. Il resulte qu'elle presente des avantages importants: tres bonne generalite, caracterisation large bande d'une structure apres une seule simulation, possibilite de prendre en compte a la fois des structures fermees et des structures ouvertes. Dans le chapitre 3, la methode a ete validee par l'etude d'une cavite resonante a 30 ghz, d'une ligne microruban uniforme, et d'un trou metallise sur une ligne microruban. Dans le chapitre 4, une etude complete a ete effectuee sur les structures coplanaires utilisees dans les mmic. Nous avons etudie des lignes uniformes, des discontinuites uniaxiales (court- circuit, circuit ouvert, gap, saut de largeur) et des discontinuites multiaxiales (coude angle droit, te, avec ou sans ponts a air). Une etude comparative a ete realisee entre deux solutions possibles pour la suppression du mode fentes couplees dans les mmic: le pont a air et les trous metallises. Le chapitre 5 presente l'etude des interconnexions entre des modules mmic et des modules hybrides. On a ainsi presente les variations des parametres s de l'interconnexion en fonction des parametres technologiques de celle-ci. Dans le chapitre 6, la simulation d'une antenne planaire a donne des resultats tout a fait conformes aux mesures experimentales. Les conclusions de ce travail sont presentees dans le chapitre 7
34
Kochetov, Sergey V. "Time- and frequency-domain modeling of passive interconnection structures in field and circuit analysis." Magdeburg Univ, 2008. http://d-nb.info/100031684X/34.
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35
Tavakoli, Hanif. "An FRA Transformer Model with Application on Time Domain Reflectometry." Doctoral thesis, KTH, Elektroteknisk teori och konstruktion, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-48568.
Full textAbstract:
Frequency response analysis (FRA) is a frequency-domain method which is used to detect mechanical faults in transformers. The frequency response of a transformer is determined by its geometry and material properties, and it can be considered as the transformer’s fingerprint. If there are any mechanical changes in the transformer, for example if the windings are moved or distorted, its fingerprint will also be changed so, theoretically, mechanical changes in the transformer can be detected with FRA. A problem with FRA is the fact that there is no general agreement about how to interpret the measurement results for detection of winding damages. For instance, the interpretation of measurement results has still not been standardized.The overall goal of this thesis is to try to enhance the understanding of the information contained in FRA measurements. This has been done in two ways: (1) by examining the FRA method for (much) higher frequencies than what is usual, and (2) by developing a new method in which FRA is combined with the ideas of Time Domain Reflectometry (TDR). As tools for carrying out the above mentioned steps, models for the magnetic core and the winding have been developed and verified by comparison to measurements.The usual upper frequency limit for FRA is around 2 MHz, which in this thesis has been extended by an order of magnitude in order to detect and interpret new phenomena that emerge at high frequencies and to investigate the potential of this high-frequency region for detection of winding deteriorations.Further, in the above-mentioned new method developed in this thesis, FRA and TDR are combined as a step towards an easier and more intuitive detection and localization of faults in transformer windings, where frequency response measurements are visualized in the time domain in order to facilitate their interpretation.QC 20111122
36
Gibert, Pierre-Marie. "Utilisation de prédicteurs sinusoïdaux pour la simulation temporelle de systèmes électriques en courant alternatif." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1275/document.
Full textAbstract:
Simuler temporellement les réseaux électriques modernes requiert d'importants moyens de calcul de par la dimension et la raideur des systèmes différentiels algébriques résultants. De plus, la fréquence d'oscillation de certains signaux simulés contraint fortement le pas d'intégration des schémas classiques, y compris en régime établi où ils sont proches de sinusoïdes oscillant à la fréquence nominale du système. L'objectif de la méthode des prédicteurs sinusoïdaux proposée dans cette thèse est donc de tirer parti de cette propriété afin d'améliorer les performances du solveur tout en contrôlant l'erreur de calcul. Elle consiste à décomposer la solution en deux parties : une sinusoïde, dont les coefficients de Fourier sont fixés pour chaque intervalle d'intégration puis mis à jour par estimation paramétrique, et un terme de correction sur lequel le système d'EDA est reformulé et résolu à l'aide d'un schéma d'intégration à pas adaptatif. Une attention particulière a été portée au choix de l'estimateur paramétrique, ce dernier ayant un impact direct sur le pas d'intégration de par sa précision et indirect de par son effet sur la stabilité globale de la méthode. L'estimateur finalement développé consiste à calculer les coefficients de Fourier qui minimisent une mesure de la stationnarité du système. Ce dernier étant convergent en régime permanent, le terme de correction est progressivement amorti, permettant ainsi d'accroître considérablement le pas d'intégration. Cette méthode, intégrée au sein du solveur SUNDIALS IDA puis interfacée avec un moteur de calcul industriel, permet d'accélérer très nettement les simulations en comparaison avec une implémentation classiqueModern power systems time-domain simulations require important computational resources due to the resulting differential algebraic systems dimension and stiffness. In addition, some simulated signals oscillation frequency dramatically limits the classical schemes step size, even in steady-state during which they are close to sinusoids oscillating at system nominal frequency. That's why the sinusoidal predictors method proposed in this thesis aims at taking this property into account in order to enhance solver performances while controlling the integration error. It consists in decomposing the solution into two parts: a sinusoid, whose Fourier coefficients are fixed for each time integration interval and then updated by parametric estimation, and a correction term on which the DAE system is rewritten and solved using an adaptive step size integration scheme. A particular focus has been given on the estimator choice, given its precision direct impact on the step size and its indirect effect on the global method stability. The finally developed estimator consists in computing Fourier coefficients minimizing a system stationarity measurement. As it converges in steady-state, the correction term is progressively damped, which enables to considerably increase the step size. This method, integrated into the reference solver SUNDIALS IDA and interfaced with an industrial simulation engine, enables to very significantly accelerate simulations in comparison with a classical implementation
37
Yildirim, Egemen. "Development Of Multi-layered Circuit Analog Radar Absorbing Structures." Master's thesis, METU, 2012. http://etd.lib.metu.edu.tr/upload/12614314/index.pdf.
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A fast and efficient method for the design of multi-layered circuit analog absorbing structures is developed. The method is based on optimization of specular reflection coefficient of a multi-layered absorbing structure comprising of lossy FSS layers by using Genetic Algorithm and circuit equivalent models of FSS layers. With the introduced method, two illustrative absorbing structures are designed with -15 dB reflectivity for normal incidence case in the frequency bands of 10-31 GHz and 5-46 GHz, respectively. To the author&rsquos knowledge, designed absorbers are superior in terms of frequency bandwidth to similar studies conducted so far in the literature. For broadband scattering characterization of periodic structures, numerical codes are developed. The introduced method is improved with the employment of developed FDTD codes to the proposed method. By taking the limitations regarding production facilities into consideration, a five-layered circuit analog absorber is designed and manufactured. It is shown that the manufactured structure is capable of 15 dB reflectivity minimization in a frequency band of 3.2-12 GHz for normal incidence case with an overall thickness of 14.2 mm.
38
Kochetov, Sergey V. [Verfasser]. "Time- and frequency-domain modeling of passive interconnection structures in field and circuit analysis / von Sergey V. Kochetov. Otto-von-Guericke-Universität Magdeburg." Magdeburg : Univ, 2008. http://d-nb.info/100031684X/34.
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Zhao, Bo. "THE APPLICATION OF DISCONTINUOUS GALKERIN FINITE ELEMENT TIME-DOMAIN METHOD IN THE DESIGN, SIMULATION AND ANALYSIS OF MODERN RADIO FREQUENCY SYSTEMS." UKnowledge, 2011. http://uknowledge.uky.edu/gradschool_diss/186.
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The discontinuous Galerkin finite element time-domain (DGFETD) method has been successfully applied to the solution of the coupled curl Maxwell’s equations. In this dissertation, important extensions to the DGFETD method are provided, including the ability to model lumped circuit elements and the ability to model thin-wire structures within a discrete DGFETD solution. To this end, a hybrid DGFETD/SPICE formulation is proposed for high-frequency circuit simulation, and a hybrid DGFETD/Thin-wire formulation is proposed for modeling thin-wire structures within a three-dimensional problem space. To aid in the efficient modeling of open-region structures, a Complex Frequency Shifted-Perfectly Matched Layer (CFS-PML) absorbing medium is applied to the DGFETD method for the first time. An efficient CFS-PML method that reduces the computational complexity and improves accuracy as compared to previous PML formulations is proposed. The methods have been successfully implemented, and a number of test cases are provided that validate the proposed methods. The proposed hybrid formulations and the new CFS-PML formulation dramatically enhances the ability of the DGFETD method to be efficiently applied to simulate complex, state of the art radio frequency systems.
40
Moreau, Maxime. "Modélisation haute fréquence des convertisseurs d'énergie : application à l'étude des émissions conduites vers le réseau." Phd thesis, Ecole Centrale de Lille, 2009. http://tel.archives-ouvertes.fr/tel-00579671.
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Ces travaux de recherche portent sur la problématique CEM (Compatibilité Electromagnétique) en électronique de puissance. Cette étude s'intéresse particulièrement à la modélisation HF (haute fréquence) des convertisseurs d'énergie dans le but d'étudier la propagation des perturbations conduites vers le réseau avec ou sans l'utilisation du RSIL (Réseau Stabilisateur d'Impédance de Ligne). Une première partie présente les outils de modélisation des sources de perturbation dans les convertisseurs statiques.La seconde partie est consacrée à la modélisation HF d'un système d'entraînement à vitesse variable. L'onduleur de tension triphasé est représenté par trois générateurs équivalents afin de reconstituer le découpage des tensions de sortie. Un modèle HF du câble blindé de 4 conducteurs tenant compte de la dissymétrie est ensuite proposé. Les résultats de simulation ont été validés par des relevés expérimentaux. La comparaison montre qu'il est possible de modéliser correctement le comportement HF du dispositif jusqu'à 20MHz.Une troisième partie porte sur la propagation des perturbations conduites vers le réseau sans RSIL. Il a fallu pour cela déterminer et modéliser l'impédance du réseau. L'influence du pont redresseur à diodes sur la propagation des perturbations de mode commun a ensuite été étudiée. Les résultats de simulation montrent que l'impact de ces perturbations sur la tension réseau est prépondérant lorsque le pont redresseur est à l'état bloqué. Les résultats expérimentaux ont permis de valider cette étude. Ce travail se termine par une étude préliminaire sur l'association de deux convertisseurs connectés localement à une même source d'énergie
41
陽紀, 池田, and Yoki Ikeda. "垂直導体のサージ伝搬特性を考慮した風力発電タワー周波数依存回路解析モデル." Thesis, https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB12902988/?lang=0, 2015. https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB12902988/?lang=0.
Full textAbstract:
風力発電システムは、現在世界中で普及しているが、その地上高と立地条件からしばしば落雷の被害を受け、稼働率の低下が問題視されている。本論文は、垂直導体である風力発電タワーにおける雷サージ解析の高精度化、高速化を目的とした垂直導体回路解析モデルの提案、およびその有用性のについて述べるとともに、風力発電所や洋上風車への拡張性についてまとめたものである。博士(工学)
Doctor of Philosophy in Engineering
同志社大学
Doshisha University
42
Azevedo, Ana Claudia de. "Estresse eletromecânico em transformadores causado por curtos-circuitos passantes e correntes de energização." Universidade Federal de Uberlândia, 2007. https://repositorio.ufu.br/handle/123456789/14359.
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Power transformers are quite costly and essential to provide reliable electrical power system operation. Besides their maintenance or substitution costs, transformer failures must be taken into account, since its will have a large impact on the utility financial health due to the temporary loss of power delivery capability. Concerning transformer failure statistics, investigations carried out in many utilities in the world reveal that the effect of electromechanical stress caused by short-circuit currents is a relevant cause of failure in such equipment and they cause onerous financial damage. Failures caused by mechanical stress due to external short-circuit and due to inrush currents are an important aspect to be considered. The excessive strength caused in transformer conductors/windings due to electromagnetic forces can reduce the transformer lifetime or even cause irreversible damages of them. Therefore, the investigation of the harmful
effects caused by transient phenomena becomes imperative. With this in mind, this
work aims at investigating the electromagnetic forces and mechanical stresses due to external short-circuit and inrush currents inside the transformer. The studies are carried out using a time domain transformer model based on magnetomotive forces and magnetic reluctances, which allows simulating the transformer transient and steady state behavior regarding the electric, magnetic and mechanical aspects. The methodology is applied in two transformer models operating under rated and short-circuit conditions. Due to the lack of mechanical stress experimental values, a comparative performance analysis is obtained by comparing the simulated results and the well accepted results from finite element program. The results obtained from simulations are evaluated through of the impacts provoked in the variables used to analyze the mechanical stresses which occur in the transformers due to short-circuit and inrush currents. From the mechanical stress calculated it is presented a methodology that establishes a correlation between the phenomena here investigated and the impact in the transformer lifetime. This can assist, previously, in the reduction of the number of
unexpected failures and, consequently, in financial damages.Transformadores de potência são dispositivos fundamentais para a operação de sistemas de potência e têm um peso significativo no custo total de uma instalação. Além dos custos de manutenção e substituição, as falhas nos transformadores devem ser levadas em consideração, no sentido de manter tanto a continuidade do fornecimento de energia como os padrões mínimos de qualidade estabelecidos para o insumo energia elétrico, aliado ao equilíbrio financeiro das empresas. Estudos realizados por concessionárias de diversos países deixam evidentes os enormes prejuízos financeiros das empresas do setor elétrico, devido às falhas mecânicas em transformadores. Defeitos provocados pelos esforços mecânicos decorrentes de correntes de curtos-circuitos passantes e correntes de inrush se constituem como importantes causadores de falhas em transformadores. Os esforços adicionais causados nos condutores/bobinas de transformadores, devido ao acréscimo das forças eletromagnéticas resultantes, podem, em alguns casos, vir a reduzir a vida útil de transformadores ou até mesmo provocar a sua perda total. A investigação dos efeitos danosos causados pelos fenômenos mencionados, portanto, torna-se imperativa. Nessa perspectiva, a presente tese tem por objetivo investigar as forças eletromagnéticas e o estresse mecânico resultantes de cor- rentes de curtos-circuitos passantes e correntes de energização que se estabelecem no interior de transformadores. Para alcançar tal propósito, é empregada uma modelagem computacional no domínio do tempo baseada em forças magnetomotrizes e relutâncias magnéticas. Este modelo permite simulações de fenômenos de regime transitório e per- manente, além de possibilitar o acesso às grandezas elétricas, magnéticas e mecânicas. A metodologia é aplicada a dois modelos de transformadores operando em condições nominais e em curto-circuito. Devido às dificuldades de se encontrar publicações que contenham valores de referência para validar a metodologia proposta, os resultados são comparados aos correspondentes obtidos de um tradicional e bem aceito pacote do Método dos Elementos Finitos. Os resultados oriundos das simulações são avaliados em termos do grau de impacto que é provocado nas grandezas utilizadas para aferir os esforços mecânicos a que fica submetido um transformador, quando de sua energização ou na ocorrência de curtos-circuitos passantes. A partir dos esforços mecânicos determinados é apresentada uma proposta de metodologia que estabelece uma correlação entre os fenômenos aqui estudados e o impacto sobre a vida útil de transformadores, que pode auxiliar, de maneira preditiva, na redução do número de falhas inesperadas e, em conseqüência, nos prejuízos financeiros decorrentes.
Doutor em Ciências
43
Lou, Fei. "Design, fabrication and characterization of plasmonic components based on silicon nanowire platform." Doctoral thesis, KTH, Optik och Fotonik, OFO, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-143953.
Full textAbstract:
Optical interconnects based on CMOS compatible photonic integrated circuits are regarded as a promising technique to tackle the issues traditional electronics faces, such as limited bandwidth, latency, vast energy consumption and so on. In recent years, plasmonic integrated components have gained great attentions due to the properties of nano-scale confinement, which may potentially bridge the size mismatch between photonic and electronic circuits. Based on silicon nanowire platform, this thesis work studies the design, fabrication and characterization of several integrated plasmonic components, aiming to combine the benefits of Si and plasmonics. The basic theories of surface plasmon polaritons are introduced in the beginning, where we explain the physics behind the diffraction-free confinement. Numerical methods frequently used in the thesis including finite-difference time-domain method and finite-element method are then reviewed. We summarize the device fabrication techniques such as film depositions, e-beam lithography and inductively coupled plasma etching as well as characterization methods, such as direct measurement method, butt coupling, grating coupling etc. Fabrication results of an optically tunable silicon-on-insulator microdisk and III-V cavities in applications as light sources for future nanophotonics interconnects are briefly discussed. Afterwards we present in details the experimental demonstrations and novel design of plasmonic components. Hybrid plasmonic waveguides and directional couplers with various splitting ratios are firstly experimentally demonstrated. The coupling length of two 170 nm wide waveguides with a separation of 140 nm is only 1.55 µm. Secondly, an ultracompact polarization beam splitter with a footprint of 2×5.1 μm2 is proposed. The device features an extinction ratio of 12 dB and an insertion loss below 1.5 dB in the entire C-band. Thirdly, we show that plasmonics offer decreased bending losses and enhanced Purcell factor for submicron bends. Novel hybrid plasmonic disk, ring and donut resonators with radii of ~ 0.5 μm and 1 μm are experimentally demonstrated for the first time. The Q-factor of disks with 0.5 μm radii are , corresponding to Purcell factors of . Thermal tuning is also presented. Fourthly, we propose a design of electro-optic polymer modulator based on plasmonic microring. The figure of merit characterizing modulation efficiency is 6 times better comparing with corresponding silicon slot polymer modulator. The device exhibits an insertion loss below 1 dB and a power consumption of 5 fJ/bit at 100 GHz. At last, we propose a tightly-confined waveguide and show that the radius of disk resonators based on the proposed waveguide can be shrunk below 60 nm, which may be used to pursue a strong light-matter interaction. The presented here novel components confirm that hybrid plasmonic structures can play an important role in future inter- and intra-core computer communication systems.QC 20140404
44
Wang, Zhechao. "Investigation of New Concepts and Solutions for Silicon Nanophotonics." Doctoral thesis, KTH, Mikroelektronik och tillämpad fysik, MAP, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-13029.
Full textAbstract:
Nowadays, silicon photonics is a widely studied research topic. Its high-index-contrast and compatibility with the complementary metal-oxide-semiconductor technology make it a promising platform for low cost high density integration. Several general problems have been brought up, including the lack of silicon active devices, the difficulty of light coupling, the polarization dependence, etc. This thesis aims to give new attempts to novel solutions for some of these problems. Both theoretical modeling and experimental work have been done. Several numerical methods are reviewed first. The semi-vectorial finite-difference mode solver in cylindrical coordinate system is developed and it is mainly used for calculating the eigenmodes of the waveguide structures employed in this thesis. The finite-difference time-domain method and beam propagation method are also used to analyze the light propagation in complex structures. The fabrication and characterization technologies are studied. The fabrication is mainly based on clean room facilities, including plasma assisted film deposition, electron beam lithography and dry etching. The vertical coupling system is mainly used for characterization in this thesis. Compared with conventional butt-coupling system, it can provide much higher coupling efficiency and larger alignment tolerance. Two novel couplers related to silicon photonic wires are studied. In order to improve the coupling efficiency of a grating coupler, a nonuniform grating is theoretically designed to maximize the overlap between the radiated light profile and the optical fiber mode. Over 60% coupling efficiency is obtained experimentally. Another coupler facilitating the light coupling between silicon photonic wires and slot waveguides is demonstrated, both theoretically and experimentally. Almost lossless coupling is achieved in experiments. Two approaches are studied to realize polarization insensitive devices based on silicon photonic wires. The first one is the use of a sandwich waveguide structure to eliminate the polarization dependent wavelength of a microring resonator. By optimizing the multilayer structure, we successfully eliminate the large birefringence in an ultrasmall ring resonator. Another approach is to use polarization diversity scheme. Two key components of the scheme are studied. An efficient polarization beam splitter based on a one-dimensional grating coupler is theoretically designed and experimentally demonstrated. This polarization beam splitter can also serve as an efficient light coupler between silicon-on-insulator waveguides and optical fibers. Over 50% coupling efficiency for both polarizations and -20dB extinction ratio between them are experimentally obtained. A compact polarization rotator based on silicon photonic wire is theoretically analyzed. 100% polarization conversion is achievable and the fabrication tolerance is relatively large by using a compensation method. A novel integration platform based on nano-epitaxial lateral overgrowth technology is investigated to realize monolithic integration of III-V materials on silicon. A silica mask is used to block the threading dislocations from the InP seed layer on silicon. Technologies such as hydride vapor phase epitaxy and chemical-mechanical polishing are developed. A thin dislocation free InP layer on silicon is obtained experimentally.QC20100705
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Fakhfakh, Seifeddine. "Nouvelles méthodes de caractérisation et de modélisation non-linéaire électrothermique des effets de piège dans la technologie HEMT GaN pour l’étude de la stabilité pulse à pulse dans les applications radar." Thesis, Limoges, 2018. http://www.theses.fr/2018LIMO0103/document.
Full textAbstract:
La capacité d’un émetteur radar à assurer la bonne détection des cibles mouvantes sans générer de fausses alertes dépend principalement de sa stabilité pulse à pulse qui est affectée par de nombreux facteurs tels que les effets mécaniques, thermiques et électriques. Cependant, la stabilité pulse à pulse d’un émetteur radar à impulsions est liée à celle de ses amplificateurs de puissance, et plus particulièrement à la technologie des dispositifs actifs. Dans ce sens, ce travail présente une analyse de ce critère radar au plus près du composant (au niveau d’un transistor HEMT GaN) dans le cas d’une rafale radar d’impulsions irrégulières. Un nouveau banc de mesure temporelle d’enveloppe 4-canaux à base de THA a été développé pour les besoins de mesure de stabilité pulse à pulse. Ce système de mesure permet aussi d’extraire la réponse temporelle de courant basse fréquence à des rafales irrégulières d’impulsions RF. Bien que cette configuration ait été initialement développée pour caractériser la spécification critique de la stabilité pulse à pulse pour les applications radar, elle a montré un énorme potentiel pour la modélisation des pièges lors des simulations temporelles d’enveloppe, en complément des différentes techniques de caractérisation des pièges (I-V impulsionnelle, dispersion basse-fréquence de l’admittance de sortie Y22)The capability of a radar transmitter to ensure clutter rejection depends mainly on its pulse-to-pulse stability, which is affected by many factors such as mechanical, thermal, and electrical effects. However, the P2P stability of a pulsed radar transmitter is linked to that of its power amplifiers, and more specifically on the active device technology. In this context, thiswork presents the analysis of this radar criterion at device level (GaNHEMTtransistor) in the case of a radar burst of RF pulses. A new on-wafer time-domain envelope measurement setup based on a 4-channel THA receiver has been developed to characterize pulse-to-pulse stability and the low-frequency drain current. While this setup was originally developed to characterize the critical specification of pulse-to-pulse stability for radar applications, it demonstrated a great potential for trap modeling in addition to the different characterization techniques of traps (pulsed I-V, low-frequency dispersion of Y22)
46
Prudík, Jiří. "Model metropolitní optické sítě." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217666.
Full textAbstract:
The purpose of this master’s thesis is foremost to provide a simple guide how to build elements of optical metropolitan area network. The basic model consists to sequence of construction, network topology, passive and active parts. The collection contains examples of alternative technology such as Wireless LAN with different frequency. The optical network construction based on optical cable, fibres, splices, trays, adapters, connectors and active parts for example a lot of media convertor models. After that there are demonstrating type of wavelength division multiplexer used in metropolitan area network – passive planar PCL splitter. One of the passive planar splitter are used to increase optical fibre channel. At the end of the collection a simplified examples of used measurements – optical time domain reflectometry and optical fibre transmission. Contains standard protocols or reflectogram. The conclusion of this thesis summarizes costs of FTTb (Fibre To The Building) model of optical metropolitan area network in Czech republic and future contribution for society.
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Wu, Huang-Jin, and 吳皇進. "Time-Domain Simulation for Power Electronic Circuits." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/40276132257367238557.
Full textAbstract:
博士國立臺灣大學
電機工程學研究所
87
ABSTRACT Major contributions presented in this dissertation are twofold: 1) A new and simple modeling approach, namely numerical-time reciprocal state modeling (NRSM), to large-signal dynamic simulation for resonant converters (RCs) is proposed. This dynamics information is quite significant in designing actual component ratings and high performance converters; however, it is not available in the literature for the fourth-order RCs. Because the approach only needs three relatively straightforward operations, which can be done by inspection only, to formulate numerical-time state equations for a simulation program, it is probably the simplest approach. Though the proposed approach is very simple (c.f. [29]), it provides an exact solution to the numerical-time model. These combined advantages of simplicity and accuracy would make this approach quite attractive in the study of dynamic behavior of such converters. 2) Combining the numerical-time state models for energy-storage elements with unification models of switching devices and several straightforward circuit-manipulated operations, a new and simple formulation method is proposed for power electronic circuits to obtain a reduced unification matrix (RUM). Simulation results using the RUM method demonstrate its superiority over the commonly-used MNM method, not only for memory requirements but also for computational speed. A large circuit example shows that the RUM method offers a 76.32 percent timesavings in computation. These combined advantages should make the proposed RUM method very attractive in the time-domain simulation of switched networks. For large switched networks, the decided advantages are very great.
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Fan, Zhen-Teng, and 范振騰. "Accurate time-domain current simulator for VLSI circuits." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/27643544539904388996.
Full text
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Jong, Jyh-Ming. "Time domain characterization of interconnect discontinuities." Thesis, 1991. http://hdl.handle.net/1957/36724.
Full textAbstract:
The purpose of this study is to develop experimental techniques to
characterize typical interconnect discontinuities, including bends, steps, T
junctions, vias and pads, which are the most commonly encountered
interconnections in high speed digital integrated circuits, hybrid and
monolithic microwave circuits and electronic packages. The time domain
reflection response of these elements is used to classify the interconnect
discontinuities as distributed discontinuity elements or as lumped elements
depending upon the reflected waveform. For the cases of general distributed
discontinuities including bends, steps and T junctions, the distributed
equivalent circuit model is characterized by the time dependent impedance
profile which is extracted from the time domain reflection measurements. By
using known inverse scattering techniques implemented in terms of a new
algorithm based on the transfer scattering matrix method of incremental
uniform sections, this nonuniform impedance profile is extracted and is used
to construct distributed element circuit models to represent the interconnect
discontinuities. A circuit model consisting of lumped/distributed elements,
is also developed for the interconnect discontinuities which is intended to
combine the accuracy of the distributed model with the simulation efficiency
of the lumped models. This hybrid mode reduces computer simulation time
when used as a net list for general purpose circuit simulators, such as SPICE.
For the case of discontinuities modelled as lumped elements, such as vias and
wiring pads, closed form equations based on the transfer scattering matrix
solution are derived and used to extract the lumped electrical parameters of
these elements from the time domain reflection waveform. All of these
lumped, distributed and hybrid models are validated by comparing the time
domain simulation results with Time Domain Reflectrometer ( TDR )
measurements. A procedure for extracting the excess inductances and
capacitances associated with the general discontinuities from the synthesized
nonuniform impedance profile or the distributed model is also presented in
this report. These results for excess lumped inductances and capacitances
show close agreement with the published results for these structures which
are based on the electromagnetic computation of excess currents and charges
and frequency domain measurements. Finally, some typical cases
demonstrating the effects of interconnect discontinuities in high speed
clocking systems are presented and the procedure for reducing the reflections
and transmission noise voltage by chamfering the bends and junctions is
described.Graduation date: 1992
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Kalani, Sarthak. "Voltage and Time-Domain Analog Circuit Techniques for Scaled CMOS Technologies." Thesis, 2020. https://doi.org/10.7916/d8-8ch2-7e04.
Full textAbstract:
CMOS technology scaling has resulted in reduced supply voltage and intrinsic voltage gain of the transistor. This presents challenges to the analog circuit designers due to lower signal swing and achievable signal to noise ratio (SNR), leading to increased power consumption. At the same time, device speed has increased in lower design nodes, which has not been directly beneficial for analog circuit design. This thesis presents voltage-domain and time-domain circuit scaling friendly circuit architectures that minimize the power consumption and benefit from the increasing transistor speeds.
In the voltage-domain, an on-the-fly gain selection block is demonstrated as an alternative to the traditional MDAC architecture to enhance the input dynamic range of a medium-resolution medium-speed analog-to-digital converter (ADC) at reduced supply voltages. The proposed design also eliminates the need for a reference buffer, thus providing power savings. The measured prototype enhances the input dynamic range of a 12bit, 40MSPS ADC to 80.6dB at 1.2V supply voltage.
In the time-domain, a generic circuit design approach is presented, followed by an in-depth analysis of Voltage-Controlled-Oscillator based Operational Transconductance Amplifiers (VCO-OTAs). A discrete-time-domain small-signal model based on the zero crossings of the internal VCOs is developed to predict the stability, the step response, and the frequency response of the circuit when placed in feedback. The model accurately predicts the circuit behavior for an arbitrary input frequency, even as the VCO free-running frequency approaches the unity-gain bandwidth of the closed-loop system, where other intuitive small-signal models available in the literature fail.
Next, we present an application of VCO-OTA in designing a baseband trans-impedance amplifier (TIA) for current-mode receivers as a scaling-friendly and power-efficient alternative to the inverter-based OTA. We illustrate a design methodology for the choice of the VCO-OTA parameters in the context of a receiver design with an example of a 20MHz RF-channel-bandwidth receiver operating at 2GHz. Receiver simulation results demonstrate an improvement of up to 12dB in blocker 1dB compression point (B1dB) for slightly higher power consumption or up to 2.6x power reduction of the TIA resulting in up to 2x power reduction of the receiver for similar B1dB performance.
Next, we present some examples of VCO-OTAs. We first illustrate the benefit of a VCO-OTA in a low-dropout-voltage regulator to achieve a dropout voltage of only100mV and operating down to 0.8V input supply, compared to the prototype based on traditional OTA with a minimum dropout voltage of 150mV, operating at a minimum of 1.2V supply. Both the capacitor-less prototypes can drive up to 1nF load capacitor and provide a current of 60mA. The next prototype showcases a method to reduce the power consumption of a VCO-OTA and spurs at the VCO frequency, with an application in the design of a fourth-order Butterworth filter at 4MHz. The thesis concludes with a design example of 0.2V VCO-OTA.