This research focuses on the development of engineered materials, also known as meta- materials, with desirable effective constitutive parameters: electric permittivity (epsilon) and magnetic permeability (mu) to decouple antennas and noise mitigation from electromagnetic systems. An interesting phenomenon of strong relevance to a wide range of problems, where electromagnetic interference is of concern, is the elimination of propagation when one of the constitutive parameters is negative. In such a scenario, transmission of electromagnetic energy would cease, and hence the coupling between radiating systems is reduced. In the first part of this dissertation, novel electromagnetic artificial media have been developed to alleviate the problem of mutual coupling between high-profile and ow-profile antenna systems. The developed design configurations are numerically simulated, and experimentally validated. In the mutual coupling problem between high-profile antennas, a decoupling layer based on artificial magnetic materials (AMM) has been developed and placed between highly-coupled monopole antenna elements spaced by less than Lambda/6, where Lambda is the operating wavelength of the radiating elements. The decoupling layer not only provides high mutual coupling suppression (more than 20-dB) but also maintains good impedance matching and low correlation between the antenna elements suitable for use in Multiple-Input Multiple-Output (MIMO) communication systems. In the mutual coupling problem between low-profile antennas, novel sub-wavelength complementary split-ring resonators (CSRRs) are developed to decouple microstrip patch antenna elements. The proposed design con figuration has the advantage of low-cost production and maintaining the pro file of the antenna system unchanged without the need for extra layers. Using the designed structure, a 10-dB reduction in the mutual coupling between two patch antennas has been achieved. The second part of this dissertation utilizes electromagnetic artificial media for noise mitigation and reduction of undesirable electromagnetic radiation from high-speed printed-circuit boards (PCBs) and modern electronic enclosures with openings (apertures). Numerical results based on the developed design configurations are presented, discussed, and compared with measurements. To alleviate the problem of simultaneous switching noise (SSN) in high-speed microprocessors and personal computers, a novel technique based on cascaded CSRRs has been proposed. The proposed design has achieved a wideband suppression of SSN and maintained a robust signal integrity performance. A novel use of electromagnetic bandgap (EBG) structures has been proposed to mitigate undesirable electromagnetic radiation from enclosures with openings. By using ribbon of EBG surfaces, a significant suppression of electromagnetic radiation from openings has been achieved.

Design metrics such as area, timing and power are generally considered as the primary criteria in the design of modern day circuits, however, the minimization of power supply noise, among other noise sources, is appreciably more important since not only can it cause a degradation in these parameters but can cause entire chips to fail. Ensuring the integrity of the power supply voltage in the power distribution network of a chip is therefore crucial to both building reliable circuits as well as preventing circuit performance degradation. Power supply noise concerns, predicted over two decades ago, continue to draw significant attention, and with present CMOS technology projected to keep on scaling, it is shown in this work that these issues are not expected to diminish. This research also considers the management and on-chip detection of power supply noise. There are various methods of managing power supply noise, with the use of decoupling capacitors being the most common technique for suppressing the noise. An in-depth analysis of decap structures including scaling effects is presented in this work with corroborating silicon results. The applicability of various decaps for given design constraints is provided. It is shown that MOS-metal hybrid structures can provide a significant increase in capacitance per unit area compared to traditional structures and will continue to be an important structure as technology continues to scale. Noise suppression by means of current shifting within the clock period of an ALU block is further shown to be an additional method of reducing the minimum voltage observed on its associated supply. A simple, and area and power efficient technique for on-chip supply noise detection is also proposed.

In this thesis, I will present the experimental results of the dynamics of superconducting single electron transistors (sSETs), under the influence of tunable dissipation. The sSET, consisting of two dc SQUIDs in series and the third gate electrode, is deposited onto a GaAs/AlGaAs heterostructure which contains a two dimensional electron gas plane 100nm beneath the substrate surface. The Josephson coupling energy, charging energy and dissipation related Hamiltonian can all be tuned in situ, while keeping others unchanged. We measured the switching current statistics and the transport properties, as a function of the dissipation and gate charge at different temperatures. If the sSET is in the classical regime where phase is a good quantum variable, we found that the switching current and corresponding Josephson energy decrease as dissipation increases. Our observation agrees qualitatively with the theoretical calculation of a single Josephson junction with dominant Josephson energy, in a frequency dependent dissipative environment where energy barrier decreases as dissipation increases in thermally activated escape regime. This dissipation dependence result can be understood as the consequence of a reduced quantum fluctuations in the charge numbers. Whereas in the charging regime, the switching current shows a 1e periodicity with respect to gate charge, indicating a pronounced charging effect. At a specific gate charge number, quantum fluctuations of the phase variable are compressed as dissipation increases, resulting in an enhanced switching current and Josephson energy. This result matches the theory of a sSET capacitively coupled to a dissipative environment qualitatively. The temperature dependence of the switching current histogram indicates the existence of both quantum and classical thermal phase diffusion. Moreover, quantum charge fluctuations are minimized at the degeneracy point, causing a sharp dip on the width of the switching current histogram. For a sSET with comparable Josephson energy and charging energy, quantum fluctuations of both phase and charge variables are significant. The influence of dissipation on the dynamics of the device is distinct in the classical and charging regimes. Dissipation compresses quantum phase fluctuations in the charging regime, whereas reduces the quantum charge fluctuations in the classical regime. The transition between these two regimes is found to be determined by the tunnel resistance of the SQUID. The competition between Josephson and charging energies, however, is not the intrinsic parameter of this transition. Our results imply that a detailed theoretical calculation of a sSET with comparable Josephson coupling energy and charging energy under the influence of dissipation is needed.

The main objective of this thesis is to develop models for the power distribution network of high performance gigascale chips. The two main concerns in distributing power in a chip are voltage drop and electromigration-induced reliability failures. The voltage drop on the power distribution network is due to IR-drop and simultaneous switching noise. IR-drop is the voltage drop due to current passing through the resistances of the power distribution network. Simultaneous switching noise is due to varying current passing through the inductances of the power distribution network. Compact physical models are derived for the IR-drop and electromigration for different types of packages. These chip-package co-design models enable designers in the early stages of the design to estimate the on-chip interconnect resources, and also to choose type and size of the package required for power distribution. Modeling of the simultaneous switching noise requires the simulation of a large circuit with thousands of inductances. The main obstacle challenging the simulation of a simultaneous switching noise circuit model is the computing resources required to solve the dense inductance matrix. In this work, a new relative inductance matrix is introduced to solve massively coupled RLC interconnects. It is proven that the analysis using this method is accurate for a wide frequency range and all configurations. Using the new inductance matrix makes the circuit simulations significantly faster without losing accuracy.

Optical packet switching (OPS) is one of the more promising solutions for meeting the diverse needs of broadband networking applications of the future. By virtue of its small data traffic granularity as well as its nanoseconds switching speed, OPS can be used to provide connection-oriented or connectionless services for different groups of users with very different networking requirements. The optical buffer and the switch fabric are two of the most important components in an OPS router. In this research, novel designs for the optical buffer and switch fabric are proposed and experimentally demonstrated. In particular, an optical buffer that is based on a folded-path delay-line tree architecture will be discussed. This buffer is the most compact non-recirculating optical delay line buffer to date, and it uses an array of high-speed ON-OFF optical reflectors to dynamically reconfigure its delay within several nanoseconds. A major part of this research is devoted to the design and performance optimization of these high-speed reflectors. Simulations and measurements are used to compare different reflector designs as well as to determine their optimal operating conditions. Another important component in the OPS router is the switch fabric, and it is used to perform space switching for the optical packets. Optical switch fabrics are used to overcome the limitations imposed by conventional electronic switch fabrics: high power consumption and dependency on the modulation format and bit-rate of the signals. Currently, only those fabrics that are based on the broadcast-and-select architecture can provide truly non-blocking multicast services to all input ports. However, a major drawback of these fabrics is that they are implemented using a large number of optical gates based on semiconductor optical amplifiers (SOA). This results in large component count and high energy consumption. In this research, a new multicast-capable switch fabric which does not require any SOA gates is proposed. This fabric relies on a passive all-optical gate that is based on the Four-wave mixing (FWM) wavelength conversion process in a highly-nonlinear fiber. By using this new switch architecture, a significant reduction in component count can be expected.

In recent years, due to the rapid development of electronic products, non-volatile memory has become more and more important. However, flash memory has faced some physical limits bottleneck with size scaling-down. In order to overcome this problem, alternative memory technologies have been extensively investigated, including ferroelectric random access memory (FeRAM), magneto resistive RAM (MRAM), phase-change RAM (PRAM), and resistive RAM (RRAM). All of this potential next generation non-volatile memory, the resistive random access memory has most advantages such as simple structure, lower consumption of energy, lower operating voltage, high operating speed, high storage time and non-destructive access, which make it be the most potential candidate of the next generation non-volatile memory. Many studies have proposed to explain the resistance switching phenomenon, which is due to the metallic filament or the oxygen vacancies. Therefore, in order to investigate the influence of resistance switching characteristic by metal or oxygen, we choose the non-metal contained boron oxy-nitride film as the insulator layer and successfully make the resistance has the switchable characteristic of this device. Furthermore, we improved the iv stability by using the Gadolinium-doped method in the boron oxy-nitride based film. In addition, we observed the negative current differential phenomenon during the set process, which can further controlled by lower operating voltage to achieve the interfacial resistance switching. We think that is due to the formation of nitrogen titanium oxide at the interface between insulator layer and titanium nitride electrode, which caused the Schottky barrier formation and reduced the current flow. In addition, current conduction fitting can also confirm this hypothesis. Besides, titanium nitride easily bond with oxygen ions; moreover, the oxygen ions can be easily disturbed at higher temperature ambient. We believed there may easily form the nitrogen titanium oxide layer in higher temperature environment; which also improve by a series of varied temperature experiments. However, this nitrogen titanium oxide layer formed naturally very easily, resulting in an inevitable problem of data retention time, which wish to be resolved in the future.

¡@¡@We consider output voltage regulation of a novel twin-buck switching power converters with so-called zero voltage switching (ZVS) and zero current switching (ZCS). In order to observe the constraints imposed by ZVS and ZCS, it is necessary to adopt the pulse frequency modulation (PFM) technique, which lead to a switching system with aperiodic operating cycles. The control design is based on a sampled data model of the original switching dynamics and a linear quadratic criterion that takes the at-sampling behaviour into account. The applicability of the proposed controller is validated via numerical simulations written in MATLAB and SIMULINK. The controller is realized using Field Programmable Gate Array (FPGA). The experimental results indicate that the feedback system have good transient response and adequate robustness margin against source and load variation, which verify the applicability of the proposed control design approach.

During the business cycle, how the firms' marketing expenses affect the stock returns vary with economy condition. Although prior studies have focused on how change in advertising and research and development (R&D) affect firms during recessions, those studies ignored the interaction between advertising and R&D. Besides, prior studies in the economics field find that the macroeconomics factors will affect firm performance. Therefore, this paper investigates which macroeconomics factor will affect firms spending on advertising and R&D to increase stock return of firms during recessions based on controlling the interaction between advertising and R&D. We match the sample of NYSE-, AMEX-, and NASDAQ-listed firms that are specified as ordinary common shares with monthly returns from the Center for Research in Securities Prices (CRSP) and with advertising and R&D from the yearly merged COMPUSTAT data for 1990 to 2010. In addition, we use the Markov switching model to identify economy condition. Meanwhile we use the portfolio analysis to classify the firms into four portfolios and though the macroeconomic model to discuss which factors impact the excess return. This study finds that controlling the condition of R&D-intensive, the default spread and growth in money supply will both affect high advertising firms, more than low advertising firm in recessions. Moreover, controlling the condition of advertising-intensive, the default spread and growth in money supply will both affect high R&D firms more than low R&D firms in recessions. These consequences may result from that during the recession, the default spread will increase and the same time the investors will not prefer high advertising and R&D firms (risky assets). On the other hand, when government implements expansionary monetary policy, investors will prefer high advertising and R&D firms. In summary, this study discuss how the macroeconomic factors affect the excess return of portfolio during recessions based on controlling the interaction between advertising and R&D. Firms could use these results to improve the performances and increase the stock returns by adjusting their spending on advertising and R&D during recessions.

In this study, we examine how advertising and customer satisfaction affect a firm¡¦s systematic risk (£]-risk) under both the highly volatile and tranquil market. This study extends prior studies that primarily considered the effects of marketing initiatives on performance metrics, focusing on systematic risk under the highly volatile and tranquil market. We examine how advertising and customer satisfaction affect a firm¡¦s £]-risk under the two distinct markets. We develop a two-stage model procedure. First, each individual firm¡¦s £]-risk in the both markets is estimated by Fama-French-Carhart-Ang 5-factor model which includes implied volatility index (VIX) as an aggregate volatility factor, along with the estimators of maximum likelihood (MLE) under the Markov switching model. Second, to examine the impact of advertising and customer satisfaction on £]-risk, we estimate empirical models for the dataset of the two distinct markets by the generalized method of moments (GMM) and the quantile regression. The results significantly support our hypotheses that higher advertising and higher customer satisfaction lower a firm¡¦s £]-risk under the overall, highly volatile and tranquil markets from the standpoint of long run. Furthermore, we find an additional discovering that from the view of short term, adverting is negatively significant associated with £]-risk under the highly volatile market, while customer satisfaction is not. Customer satisfaction, however, is negatively significant associated with £]-risk under the tranquil market, while advertising is not.

The increasing demand for real-time multimedia applications and the lack of quality of service (QoS) support in public best-effort or Internet Protocol (IP) networks has prompted many researchers to propose improvements on the QoS of such networks. This research aims to improve the QoS of real-time multimedia applications in public best-effort networks, without modifying the core network infrastructure or the existing codecs of the original media applications. A source buffering control is studied based on a fluid model developed for a single flow transported over a best-effort network while allowing for flow reversal. It is shown that this control is effective for QoS improvement only when there is sufficient flow reversal or packet reordering in the network. An alternate control strategy based on predictive multi-path switching is studied where only two paths are considered as alternate options. Initially, an emulation study is performed, exploring the impact of path loss rate and traffic delay signal frequency content on the proposed control. The study reveals that this control strategy provides the best QoS improvement when the average comprehensive loss rates of the two paths involved are between 5% and 15%, and when the delay signal frequency content is around 0.5 Hz. Linear and nonlinear predictors are developed using actual network data for use in predictive multi-path switching control. The control results show that predictive path switching is better than no path switching, yet no one predictor developed is best for all cases studied. A voting based control strategy is proposed to overcome this problem. The results show that the voting based control strategy results in better performance for all cases studied. An actual voice quality test is performed, proving that predictive path switching is better than no path switching. Despite the improvements obtained, predictive path switching control has some scalability problems and other shortcomings that require further investigation. If there are more paths available to choose from, the increasing overhead in probing traffic might become unacceptable. Further, if most of the VoIP flows on the Internet use this control strategy, then the conclusions of this research might be different, requiring modifications to the proposed approach. Further studies on these problems are needed.