Several microwave devices and antennas that are based on negative-refractive-index transmission-line (NRI-TL) metamaterials are presented in this thesis, which exhibit superior performance features compared to their conventional counterparts. These are a Wilkinson balun, a 1:4 series power divider, a four-element printed dipole array, a leaky-wave antenna, and an electrically small folded-monopole antenna. The Wilkinson balun employs +90° and −90° NRI-TL metamaterial lines at the output branches of a Wilkinson divider, to achieve a six-fold increase in the measured differential output phase bandwidth compared to that of an analogous balun employing transmission lines, while occupying only 55% of the area. The 1:4 series power divider comprises four non-radiating 0° NRI-TL metamaterial lines, each with a compact length of λ0/8, to provide equal power split to all four output ports. Compared to a conventional series power divider employing one-wavelength long transmission lines, the metamaterial divider provides a 154% increase in the measured through-power bandwidth, while occupying only 54% of the area. The metamaterial series power dividing concept is also applied to a four-element fully-printed dipole array that is designed to radiate at broadside, in order to demonstrate that the array exhibits reduced beam squinting characteristics. It is shown that the metamaterial-fed array has a measured scan-angle bandwidth that is 173% greater than an array that is fed using a conventional low-pass loaded line. The reduced-beam squinting property that NRI-TL metamaterial lines offer is subsequently exploited to create a leaky-wave antenna that radiates a near-fixed beam in the forward +45° direction, with an average measured beam squint of only 0.031°/MHz. This is achieved by operating the antenna in the upper right-handed band where the phase and group velocities are the closest to the speed of light. Finally, an electrically small antenna comprising four 0° NRI-TL metamaterial unit cells is presented which supports a predominantly even-mode current, thus enabling it to be modeled as a multi-arm folded monopole. This significantly increases its radiation resistance, which allows it to be matched to 50 Ω, while maintaining a high measured efficiency of 70%.

This report is an outcome of a master degree project at Linköpings University in co-operation with Micronic Laser Systems AB. The purpose with this master degree project was to investigate how to implement a receiver in a data transfer system. The system consists of several data channels, where every channel consists of three parts: driver, transmission lines and receiver. The driver send low amplitude differential signals via the transmission lines to the receiver that amplifies and converts it to a single-ended signal. The receiver has to be fast and be able to feed an output signal with high voltage swing. It is also needed for the receivers to have low power consumption since they are close to the load, which is sensitive to heat. Different amplifier architectures were investigated to find a suitable circuit for the given prerequisites. In this report the advantages and disadvantages of voltage and current feedback are discussed. The conclusions of this work are that in a system with an amplifier as a receiver with differential transmission lines, a single operational amplifier cannot be used. An input stage is needed to isolate the feedback net from the inputs of the operational amplifier. When fast rise time and large output swing are wanted the best amplifier architecture is current feedback amplifiers. A current feedback amplifier in CMOS with the required high voltages and slew rate is hard to realize without very high power consumption.

In this thesis, we present a new continuously variable high frequency standing wave oscillator and demonstrate its use in generating the phase locked clock signal of a digital IC. The ring based standing wave resonant oscillator is implemented with a plurality of wires connected in a mobius configuration, with a cross coupled inverter pair connected across the wires. The oscillation frequency can be modulated by coarse and fine tuning. Coarse modification is achieved by altering the number of wires in the ring that participate in the oscillation, by driving a digital word to a set of passgates which are connected to each wire in the ring. Fine tuning of the oscillation frequency is achieved by varying the body bias voltage of both the PMOS transistors in the cross coupled inverter pair which sustains the oscillations in the resonant ring. We validated our PLL design in a 90nm process technology. 3D parasitic RLCs for our oscillator ring were extracted with skin effect accounted for. Our PLL provides a frequency locking range from 6 GHz to 9 GHz, with a center frequency of 7.5 GHz. The oscillator alone consumes about 25 mW of power, and the complete PLL consumes a power of 28.5 mW. The observed jitter of the PLL is 2.56 percent. These numbers are significant improvements over the prior art in standing wave based PLLs.

An analytical solution for the coupled telegrapher’s equations in terms of the voltage and current on a homogeneous lossy transmission line and multiconductor transmission line is presented. The resulting telegrapher’s equation solution is obtained in the form of an exact time domain propagator operating on the line voltage and current. It is shown that the analytical equations lead to a stable numerical method that can be used in the analysis of both homogeneous and inhomogeneous transmission lines. A numerical dispersion relation is derived proving that this method has no numerical dispersion down to the two points per wavelength Nyquist limit. Examples are presented showing that exceptionally accurate results are obtained for lossy single and multiconductor transmission lines. The method is extended to represent the general solution to Maxwell’s differential equations in vector matrix form. It is shown that, given the electromagnetic field and boundary conditions at a given instant in time, the free space time domain propagator and corresponding dyadic Green’s functions in 1-, 2-, and 3-dimensions can be used to calculate the field at all subsequent times.

The continuous scaling of interconnect wires in deep submicron (DSM)circuits result in increased interconnect delay, power and crosstalk noise. In this dissertation, we address the problem of multi-metric optimization at post layout level in the design of deep submicron designs and develop a game theoretic framework for its solution. Traditional approaches in the literature can only perform single metric optimization and cannot handle multiple metrics. However, in interconnect optimization, the simultaneous optimization of multiple parameters such as delay, crosstalk noise and power is necessary and critical. Thus, the work described in this dissertation research addressing multi-metric optimization is an important contribution.Specifically, we address the problems of simultaneous optimization of interconnect delay and crosstalk noise during (i) wire sizing (ii) gate sizing (iii) integrated gate and wire sizing, and (iv) gate sizing considering process variations. Game the ory provides a natural framework for handling conflicting situations and allows optimization of multiple parameters. This property is exploited in modeling the simultaneous optimization of various design parameters such as interconnect delay, crosstalk noise and power, which are conflicting in nature. The problem of multi-metric optimization is formulated as a normal form game model and solved using Nash equilibrium theory. In wire sizing formulations, the net segments within a channel are modeled as the players and the range of possible wire sizes forms the set of strategies. The payoff function is modeled as (i) the geometric mean of interconnect delay andcrosstalk noise and (ii) the weighted-sum of interconnect delay, power and crosstalk noise, in order to study the impact of different costfunctions with two and three metrics respectively. In gate sizing formulations, the range of possible gate sizes is modeled as the set of strategies and the payoff function is modeled as the geome tric mean of interconnect delay and crosstalk noise. The gates are modeled as the players while performing gate sizing, whereas, the interconnect delay and crosstalk noise are modeled as players for integrated wire and gate sizing framework as well as for statistical gate sizing under the impact of process variations.The various algorithms proposed in this dissertation (i) perform multi-metric optimization (ii) achieve significantly better optimization and run times than other methods such as simulated annealing, genetic search, and Lagrangian relaxation (iii) have linear time and space complexities, and hence can be applied to very large SOC designs, and (iv) do not require rerouting or incur any area overhead. Thecomputational complexity analysis of the proposed algorithms as well as their software implementations are described, and experimental results are provided that establish the efficacy of the proposed algorithms.

Due to growth of wind power, system operators are being challenged by the integration of large wind farms into their electrical power systems. Large scale wind farm integration has adverse effects on the power system due to its variable characteristic. These effects include two main aspects: voltage stability and active line flow. In this thesis, a novel techniques to forecast active line flow and select pilot bus are introduced with wind power integration. First, this thesis introduces a methodology to forecast congestion in the transmission line with high wind penetration. Since most wind resources tend to be located far away form the load center, the active line flow is one of the most significant aspects when wind farm is connected to electrical grid. By providing the information about the line flow which can contribute to transmission line congestion, the system operators would be able to respond such as by requesting wind power or load reduction. The second objective of this thesis is to select the weakest bus, called pilot bus, among all load buses. System reliability, especially voltage stability, can be adversely affected by wind variability. In order to ensure reliable operation of power systems with wind power integration, the index to select the pilot bus is developed, and further prediction of voltage profile at the pilot bus is fulfilled. The objective function to select the pilot bus takes account of the N-1 contingency analysis, loading margin, and reactive power sensitivity. Through on the objective function, the pilot bus is representative of all load buses as well as controllable by reactive power regulation. Predicting the voltage profile at the pilot bus is also useful for system operators to determine wind power output. / text

Σκοπόςτης παρούσας εργασίαςείναι αρχικά η δημιουργία ενός μοντέλου με τα χαρακτηριστικά ενός μονωτήρα υψηλής τάσης.Το μοντέλο αυτό θα ενσωματωθεί στο μοντέλο μιας γραμμής υψηλής τάσης διπλού κυκλώματος των 400kV, για να υπολογιστούν οι επαγόμενες υπερτάσεις σε παρακείμενο υπέργειο αγωγό μεταφοράς υδρογονανθράκων. Τα παραπάνω επιτυγχάνονταιμε τη μοντελοποίηση πραγματικών πυλώνων και γραμμών του Ελληνικού συστήματος μεταφοράς καθώς και υπέργειου αγωγού υδρογονανθράκων.Η εξομοίωση υλοποιείται μέσω του προγράμματος ATP-EMTP. Για τον σχεδιασμό του μοντέλου του μονωτήρα χρησιμοποιήθηκε το μοντέλοVolt-TimeCurve. Επίσης χρησιμοποιήθηκαν δύο τύποι κεραυνού για τις προσομοιώσεις, για γρήγορο και αργό σήμα, με τιμές ρεύματος 100kA. Για το γρήγορο, οι τιμές χρόνων μετώπου και ουράς 1.2/50μs και για το αργό σήμα 10/350μs. Σε αυτή τη διπλωματική εργασία υπάρχουν 8 κεφάλαια. Στα πρώτα 5 κεφάλαια έγινε μια παράθεση πληροφοριών και θεωρητική προσέγγιση όλων των επιμέρους τμημάτων που συνθέτουν τη συνολική διάταξη της μελέτης. Στο 5ο κεφάλαιο γίνεται λεπτομερής αναφοράστο πρόγραμμα ATP-EMTP στο οποίο πραγματοποιήθηκε η προσομοίωση.Στο 6o κεφάλαιο γίνεται η μοντελοποίηση όλων των στοιχείων της διάταξης και η ενσωμάτωσή τους στοATP-EMTP. Στο 7ο κεφάλαιο γίνεται παρουσίαση του μοντέλου του μονωτήρα που αναπτύχθηκε και στο 8ο κεφάλαιο γίνεται παρουσίαση των αποτελεσμάτων της προσομοίωσης και εξάγονται κάποια συμπεράσματα σχετικά με τη διάταξη. / The purpose of this paper is , at first, to create a model with the features of a high voltage insulator. This model will be incorporated into the model of a high-voltage line double circuit 400kV, to calculate the induced transients in adjacent aboveground pipeline hydrocarbons. These goals are achieved by modeling real pillars and lines of Greek transport system and overground pipeline hydrocarbons. The simulation is implemented through the ATP-EMTP. The model Volt-Time Curve is used for the modeling of the insulator. Also, two types of lightning are used for the simulations, for fast and slow signal, with current values 100kA. For fast signal, the prices of front and tail time are 1.2 / 50ms and for slow signal 10 / 350ms. In this thesis there are 8 chapters. In the first five chapters was a quote and information theoretical approach to all individual parts that make up the overall layout of the study. The 5 chapter is a detailed reference to the ATP-EMTP program which performed the simulation. The 6 chapter is the modeling of all elements of the layout and the incorporation into the ATP-EMTP. In chapter 7 we present the model of the insulator developed and in chapter 8 we present the simulation results and draw inferences about the layout.

Il existe aujourd'hui un enjeu sociétal majeur à s'intéresser à la propagation du son en milieu extérieur etnotamment, dans notre contexte, à diminuer l'incertitude sur l'estimation des niveaux sonores et améliorer ainsi laprécision des diverses analyses, du bureau d'étude à l'institut de recherche. Dans le cadre de l'acoustiqueenvironnementale, l'influence des conditions météorologiques sur la propagation acoustique en milieu extérieurpeut être importante. Il est donc nécessaire d'appréhender et de quantifier les phénomènes météorologiques demicro-échelles que l'on observe dans la couche limite atmosphérique.Dans ce but, le modèle météorologique de recherche de Météo-France (Meso-NH) a été utilisé. Après avoircomparé les résultats de ce modèle à très fine résolution (de l'ordre du mètre) à l'aide des bases de données de deuxcampagnes expérimentales (Lannemezan 2005 et la Station de Long Terme), il s'est avéré nécessaire de développercet outil en intégrant la prise en compte de la force de traînée des arbres. Dès lors, les résultats issus de Meso-NH surles champs de vent, de température et d'énergie cinétique turbulente aparraissent satisfaisants. Ces informationssont par la suite utilisées en données d'entrée du modèle de propagation acoustique.Le modèle acoustique temporel utilisé est basé sur la méthode Transmission Line Matrix (TLM). Sondéveloppement a été effectué dans le but d'être appliqué à la propagation acoustique en milieu extérieur : prise encompte du relief, de différents types de sol, des conditions atmosphériques, etc. La validation numérique de laméthode TLM, par comparaison avec d'autres modèles (analytique et numérique de type Equation Parabolique), apermis de montrer la pertinence de son utilisation dans le cadre de l'acoustique environnementale.Enfin, à l'aide de ces modèles, des niveaux sonores simulés sous différentes conditions de propagation(favorables, défavorables, homogènes) ont été comparés aux mesures in-situ réalisées lors de la campagneexpérimentale de Lannemezan 2005. Les résultats se sont avérés très satisfaisants au regard de la variabilité desphénomènes observés. Cependant, l'utilisation des champs issus d'un modèle micro-météorologique de type Meso-NH reste délicate du fait de la forte sensibilité du niveau sonore aux profils verticaux de célérité du son. L'étude defaisabilité sur une expérience plus complexe (la Station de Long Terme) est encourageante et, à condition de disposerd'importants moyens de calculs, elle permet de considérer la TLM comme une nouvelle méthode de référence etainsi, d'envisager d'élargir son domaine d'utilisation à d'autres applications.

In recent years, the number of available cores in a processor are increasing rapidly while the pace of performance improvement of an individual core has been lagged. It led application developers to extract more parallelism from a number of cores to make their applications run faster. However, writing a parallel program that scales well with the increasing core counts is challenging. Consequently, many parallel applications suffer from performance bugs caused by scalability limiters. We expect core counts to continue to increase for the foreseeable future and hence, addressing scalability limiters is important for better performance on future hardware. With this thesis, I propose both software frameworks and hardware improvements that I developed to address three important scalability limiters: load imbalance, barrier latency and increasing on-chip packet latency. First, I introduce a debugging framework for load imbalance called LIME. The LIME framework uses profiling, statistical analysis and control flow graph analysis to automatically determine the nature of load imbalance problems and pinpoint the code where the problems are introduced. Second, I address scalability problem of the barrier, which has become costly and difficult to achieve scalable performance. To address this problem, I propose a transmission line (TL) based hardware barrier support, called TLSync, that is orders of magnitude faster than software barrier implementation while supports many (tens) of barriers simultaneously using a single chip-spanning network. Third and lastly, I focus on the increasing packet latency in on-chip network, and propose a hybrid interconnection where a low-latency TL based interconnect is synergistically used with a high-throughput switched interconnect. Also, a new adaptive packet steering policy is created to judiciously use the limited throughput available on the low-latency TL interconnect.

The main focus of this thesis is placed on high frequency PCB signal Integrity Is-sues and RF/Microwave filters using EBG structures. From the signal Integrity aspect, two topics were mainly discussed. On one hand, the effect of increasing frequency on classical design rules for crosstalk reduction in PCBs was investigated experimentally and by full-wave simulations. An emphasis was placed on the 3×W spacing rule and the use of guard traces. Single-ended and differential transmission lines were considered. S-parameter measurements and simu-lations were carried out at high-frequency (up to 20 GHz). The results emphasize the necessity to reevaluate traditional design rules for their suitability in high frequency applications. Also, the impacts of using guard traces for high frequency crosstalk re-duction were clearly pointed out. On the other hand, the effect of high loss PCB ma-terials on the signal transmission characteristics of microstrip lines at high frequency (up to 20 GHz) was treated. Comparative studies were carried out on different micro-strip configurations using standard FR4 substrate and a high frequency dielectric ma-terial from Rogers, Corporation. The experimental results highlight the dramatic im-pact of high dielectric loss materials (FR4 and solder mask) and magnetic plating metal (nickel) on the high frequency signal attenuation and loss of microstrip trans-mission lines. Besides, the epoxy-based SU8 photoresist was characterized at high frequency (up to 50 GHz) using on-wafer conductor-backed coplanar waveguide transmission lines. A relative dielectric constant of 3.2 was obtained at 30 GHz. Some issues related to the processing of this material, such as cracks, hard-skin, etc, were also discussed. Regarding RF/Microwave filters, the concept of Electromagnetic Band Gap (EBG) was used to design and fabricate novel microstrip bandstop filters using periodically modified substrate. The proposed EBG structures, which don’t suffer conductor backing issues, exhibit interesting frequency response characteristics. The limitations of modeling and simulation tools in terms of speed and accuracy are also examined in this thesis. Experiments and simulations were carried out show-ing the inadequacies of the Spice diode model for the simulations in power electronics. Also, an Artificial Neural Network (ANN) model was proposed as an alternative and a complement to full-wave solvers, for a quick and sufficiently accurate simulation of interconnects. A software implementation of this model using Matlab’s ANN toolbox was shown to considerably reduce (by over 800 times) the simulation time of microstrip lines using full-wave solvers such as Ansoft’s HFSS and CST’s MWS. Finally, a novel cooling structure using a double heatsink for high performance electronics was presented. Methods for optimizing this structure were also discussed. / QC 20100809