Recent expansion of the wireless infrastructure has led to a dramatic increase in the use of consumer wireless devices. This trend is driving the development of reconfigurable, high performance and inexpensive microwave components. One technology that promises to help meet some of these demands involves the use of periodic structures, also known as electromagnetic band gap (EBG) structures. The use of these EBG structures coupled with micromachining fabrication techniques provides the possibility of producing inexpensive, small and reconfigurable filters that can be used for many microwave applications. With this technology, an electronically reconfigurable EBG crystal has been developed that demonstrates contrast ratios of more than 30 dB between configuration states. This device has led to the development of a microstrip coupled EBG resonator, and then a reconfigurable microstrip coupled EBG resonator. Quality factors on the order of 400 have been demonstrated for these inexpensive and easy to integrate high performance microwave resonators. The first step towards the use of these EBG resonators in a microwave diplexer has been completed. A high performance single pole microwave diplexer has been designed, fabricated and tested using DuroidRTM circuit board material from Rogers Corporation. This diplexer exhibits channel bandwidths of less than 3%, and was used as a test structure for subsequent construction on silicon. Using silicon micromachining techniques the diplexer has been fabricated using silicon wafers. This silicon diplexer has shown improved performance over the Duroid® device in channel bandwidth (<1.6%), insertion loss (<1.5 dB), and channel-to-channel isolation (>26 dB). The development of each of these devices, including the simulated and measured results are be presented along with a discussion of the development path towards a reconfigurable EBG diplexer on silicon.

The effect of homogeneous contamination on the oxide integrity is studied by electrical measurements. The contamination is introduced in the Buffered Oxide Etchant (BOE) used for the pre-oxidation clean. The DC parametric test of forcing 1 nA and measuring voltage across the oxide is used to relate contamination to the leakage current and also to the number of failures. The factors affecting the measured voltage such as temperature, light and noise are eliminated so that contamination dominates the change in the measured voltage. The current-transport mechanism through the oxide was found to obey the Fowler-Nordheim equation at high fields. The barrier height at both interfaces was lowered in some devices. A technique for measuring the low-field breakdown which is caused by defects in the oxide is developed.

Laterally non-uniformly doped 0.1-μm pocket n-MOSFETs satisfying specifications of off-state current, on-state current, sensitivity of off-state current to channel length and 1V power-supply voltage have been designed for low-voltage low-power applications. To determine a viable range of the deep-submicron pocket n-MOSFET structural parameters---the dopant concentration at the center region (Nc), the dopant concentration at the pocket region (Np) and the length of the pocket region (Lp), a unique viable design space locating the deep-submicron devices meeting all the device specifications have been constructed, using computer algorithms developed and implemented in the programming language of the two-dimensional device simulator, Medici. For known Nc, vs. Lp, the pocket n-MOSFETs for low-power applications are located in an upper area of higher Np vs. Lp of the viable design space while the devices for high-performance applications are located in a lower area of lower Np vs. Lp of the viable design space. Well-designed deep-submicron pocket n-MOSFETs prove to be promising candidates to improve short-channel effects as well as switching performance in comparing the 0.1-μm pocket n-MOSFETs located within the viable design space to 0.1-μm conventional bulk n-MOSFETs selected to meet the same specifications. The 0.1-μm pocket n-MOSFETs located within the viable design space can be partitioned into two types of pocket devices based on gate controllability of channel- and depletion-layer charges. Analytical models for subthreshold and above-threshold currents in the deep-submicron pocket n-MOSFETs have been developed for the first time to generate the off-state and the on-state currents, and the design-space boundaries for the on- and the off-state currents. The models are based on solutions of the drift-diffusion current transport and the 1-D Poisson's equations, the charge sheet approximation, subthreshold surface potential models based on solutions of the quasi-two-dimensional Poisson's equation, a quasi-two-dimensional velocity saturation model, realistic mobility models, and analytical formulas for model parameters. The analytical models provide explicit relations between process, device and model parameters of the deep-submicron pocket n-MOSFETs, and reduce time and cost of the two-dimensional device simulation. Some algorithms developed for generating ID - V DS characteristics and constructing the design-space boundaries are described.

Model order reduction methodologies are presented for semi-discrete electromagnetic systems obtained from the spatial discretization of the hyperbolic system of Maxwell's equations. Different reduced-order modeling algorithms, i.e., Pade via Lanczos (PVL), multiple point PVL, Krylov, rational Krylov, PVL with expansion at infinity, are presented and applied for model order reduction and the properties of these algorithms are discussed. The implementation of the model order reduction methodologies to a full-wave frequency domain electromagnetic system simulator (ROMES) is discussed in detail. Scattering parameters are calculated for several electromagnetic systems with discontinuities. A time domain simulation framework is also introduced for transmission line embedded systems described by the Telegrapher's equations. The time domain convolution approach is selected to perform the transmission line embedded circuit simulations. Derivations for Closed-form triangle impulse responses (TIR) are discussed and numerical examples are presented. The developed triangle impulse responses are used to perform time-domain circuit simulations. The effects of frequency-dependent lossy transmission lines on signal integrity and causality issues associated with the transmission line parameters ( R, L, C, and G) in Telegrapher's equation are discussed. The presented research provides an accurate and efficient way to characterize electromagnetic systems for high-speed circuit applications in the frequency domain and methods to simulate these circuits in the time domain.

This dissertation is concerned with the introduction of a systematic way of modeling image processing. A dynamic imaging system model constructed from an information theory framework is proposed. Unlike an earlier simple model, the proposed dynamic imaging system (DIS) model is suitable for a wide range of applications. This DIS model is inspired by the Shannon communication theory. The Shannon communication theory is credited for the rapid development of the communication industry. Currently, most image processing researchers focus on developing fast algorithms and better hardware. An information theoretic-based approach to image processing could bring as large an impact to the image processing area as Shannon's communication theory had on the communications area. This proposed DIS model will use the information obtained from the acquired images to provide an estimation of the unknown atmospheric turbulence, vibration, etc. It will also automatically adjust the sampling rate, wavelength band, and algorithms of choice, to produce the best possible restored image with limited information under uncertainty. This dissertation develops the concept of the DIS model including its basic components. We have implemented three parts of this system. First, we implemented a noise removal algorithm based on the Markov random field (MRF). It is shown that this algorithm achieves better performance than other MRF-based algorithms in noise removal. Second, we have implemented a hybrid maximum likelihood/projection-on-convex-set image restoration algorithm and demonstrate that it outperforms the maximum likelihood algorithm. Third, we have implemented a self-organized map-based image restoration algorithm and compare its performance to several well-known methods. It can be implemented in parallel processing to achieve super-resolution in real time without performing a time consuming iteration process. The impact of the development of these DIS system critical components is discussed and future research areas are elucidated.

A Charge-Coupled Device (CCD) based electronic imaging system is proposed to overcome limitations of conventional film/screen mammography systems at no additional risk or discomfort to the patient. This thesis presents the design, implementation and evaluation of a number of prototype systems incorporating the latest advances in x-ray intensifying phosphor screen, fiber optic reducer, and CCD technologies. System design is based on an x-ray intensifying screen optically coupled to a high resolution, cooled, scientific CCD through a fiber optic reducer. The performance of the prototype system is compared to theoretical predictions, to the ideal x-ray detector, and to conventional film/screen detectors. Images of breast phantoms captured by the prototype CCD-based system and by conventional mammography systems are presented. Experimental results indicate that the CCD-based system can provide "film quality" images within seconds of x-ray exposure in needle localization, fine-needle aspiration biopsy, and magnification procedures in mammography.

The effects of ionizing-radiation-induced oxide-trapped and interface-trapped charges on gate-charge measurements of power MOSFETs are investigated. Both radiation-hardened and commercial DMOS power transistors are tested in this study. Experimental results show that: (1) the radiation-induced interface-trapped charge is related to the changes in the plateau length, and (2) the radiation-induced charges at threshold can be directly measured from the changes in the gate-to-source charge. A new charge separation technique based on the gate-charge measurement is developed. Moreover, the radiation-induced changes in the gate-charge curve provide information on the shift in threshold voltage, the increase in the plateau length, and the effective changes in gate-to-source capacitance and charge. This information should be used by the power-supply designers to compensate for radiation-induced changes in the power-MOSFET characteristics.

Frequently, the design of integrated circuits cannot be accomplished by purely analytical techniques. Accurate and efficient algorithms for numerical circuit simulation are important tools. Several circuit simulators, such as SPICE, have been made available for this task. Contrary to many other applications of numerical system simulation, integrated circuit problems don't lend themselves to a formulation of state-space models, since the space charge in a p-n junction is a nonlinear and noninvertible function of the voltage across the junction. Therefore, it is necessary to employ numerical differentiation instead of numerical integration in this type of simulation study. The numerical algorithms employed in today's circuit simulators are fairly primitive. SPICE, for example, offers only two very simple implementations of the trapezoidal rule and of the backwards differentiation formula. This thesis describes the design and implementation of DBDF, a specification of a numerical method in Nordsieck format for solving circuit simulation problems. A formal stability and truncation error analysis are included.

We study the problem of wave propagation in a parallel plate waveguide with an iris. We use Green's function techniques to model the field behavior inside the waveguide. We formulate an integral equation whose solution will allow us to solve for the fields everywhere within the guide. We solve the integral equation by employing both the method of moments and a low-frequency approximation. We next develop a power balance theorem which relates the modal coefficients of the propagating modes in an exact relation. From the numerical solution, we can generate numerical approximations to the modal coefficients. We investigate if and when our numerical approximations to the modal coefficients satisfy the power balance theorem. Finally, we derive a generalized power balance theorem for scattering by obstacles and junctions inside a waveguide of arbitrary, uniform cross-sectional area.

A microprocessor controlled auto sun-tracking 10-channel solar radiometer system has been designed and fabricated. The instrument measurements are employed in determining the atmospheric optical depths at 10 discrete wavelengths through the visible and near IR regions. The solar radiometer consists of 10 parallel Field Of View (FOV) telescopes which are all pointed towards the sun via an active auto sun-tracking system. Each channel consists of a geometrical aperture-defined telescope, interference filter and silicon photodiode/op amp combination. The data is collected by a Data Acquisition System (DAS) controlled by an 8-bit microprocessor. The automated DAS tracks the sun, measures the temperature of detectors as well as the output of all 10 channels and writes these values to a RAM. At the end of data collection period the collected data can be serially transferred to an IBM compatible personal computer.