Significant progress toward a functional 73 element, 730 watt, active microwave phased array has been made. This array, designed for medical hyperthermia applications, has significant size restrictions leading to a novel space conscious design. Unlike other hyperthermia devices, each array element is designed to have full 360° phase control with better than 1° resolution. Full amplitude control, with 10 bit amplitude resolution is implemented. The array is designed to operate in the 2.45 GHz ISM band. Measured operational data is presented and is compared to simulations performed with Compact Software's Microwave Harmonica®. A sophisticated control system for the array has been designed, built and tested. The system provides 160 computer controlled 10 bit analog control lines to drive the array. Sampling of various system parameters is made possible through the use of a 96 channel, 12 bit analog to digital converter system. This system provides 4 mV resolution and a 440 Hz sampling rate for each of the 96 measurement channels.

A near-infrared spectrometer incorporating solid-state design applicable for industrial quantitative/qualitative process monitoring analysis is presented. The solid-state near-infrared spectrometer provides inherent wavelength stability necessary for long term calibration accuracy. The spectrometer consists of a 24 volt, 10 watt quartz-halogen-tungsten regulated source with optical feedback. Wavelength dispersion was accomplished using a 50 μm entrance slit, f/4, 0.25 meter spectrograph equipped with astigmatism correcting toroidal mirrors and a 300 gr/mm plane reflectance ruled grating blazed for 2000 nm peak efficiency. A 1024 element backside- illuminated Schottky-barrier PtSi photodiode array detector with wavelength response from 900-5000 nm and peak quantum efficiency of 8% at 1100 nm was operated using cryogenic cooling to reduce dark response. A readout rate of 31.25 kHz produced 41 msec integration time per array read. The readout was digitized to 16 bit resolution for subsequent data storage. This system demonstrated 1.5 nm spectral bandpass, 3 orders linear dynamic range and typical baseline rms noise level of 10⁻⁴ a.u. Using this system, quantitative/qualitative chemical analyses were performed focusing on industrial analytical chemical applications. Simultaneous quantitative multcomponent xylene isomer mixtures analysis was achieved using the solid-state near-infrared spectrometer coupled with partial least squares regression multivariate data treatment. The results demonstrate an absolute accuracy of ± 0.05, ±0.12 and ±0.09% w/v for o-, m- and p-xylene isomers respectively. In a separate chemical study, qualitative classification analysis of specially denatured alcohol mixtures was successfully performed on 53 validation samples using 35 reference samples belonging to 12 classes. The validation set included mixture sample types used for model calibration as well as others composed of compounds not used for model calibration. The multivariate cluster classification method using principal components was employed to correctly classify 100% of the validations samples analyzed. The solid-state near-infrared spectrometer was also applied for direct reaction monitoring of the O-H overtone absorption band at 1411 nm for the reaction between triisopropyl-chlorosilane and methanol. The results illustrated the utility of near-infrared functional group monitoring of reactions at relatively high concentrations for information elucidation concerning reaction initiation and completion.

A Turbo-Pascal program has been developed that will aid a circuit designer to determine which of a set of "real" circuits will best match the associated "ideal" circuit or in choosing components for a given circuit. Study one examined the Sallen and Key second-order active low-pass circuit. Wn (mean), Wn (standard deviation), Q (mean), and Q (standard deviation) were examined as a function of Q desired, distribution type and component tolerance. The sensitivity of the circuit was calculated both numerically and through program execution. In Study two a set of reference graphs were generated to compare several second order low pass, high pass, and band pass filter classes as a function of component distribution and tolerance. Study three compares the behavior of several orders of low pass MFM (Maximally Flat Magnitude) Leapfrog filters. Amax (maximum gain), Wmax (frequency of maximum gain), and the 3dB frequency were examined. (Abstract shortened with permission of author.)

<p> Power system is the backbone of modern society. Traditionally, over 90% of the electrical energy is produced by power generation systems driven by steam turbines. Recently, with the development of renewable energy resources, wind energy conversion systems are the proven solutions for the next generation sustainable energy resources. Stability and performance of these power systems are the primary concerns of power system engineers. To better characterize the dynamical behaviors of power systems in practical applications, time delays in the feedback state variables, systems modeling uncertainties, and external disturbances are included in the state space model of the power system in this work. Linear matrix inequality based robust and resilient controllers satisfying the H_infinty performance objective for time delayed power systems are proposed. Fixed time delays are assumed to exist within the system state and input signals. The system model is assumed to have unstructured bounded uncertainties and L_2 type of disturbances. Furthermore, controller gain perturbations are assumed to be of additive type. The proposed control techniques have been applied to variable speed permanent magnet synchronous generator based wind energy conversion systems, and electrical power generation systems driven by steam turbine. Computer simulations conducted in MATLAB show the eectiveness of the proposed control algorithms.</p>

A defect detection algorithm applicable for periodic VLSI circuitry is presented in this thesis. Even though the algorithm is based on the reference comparison approach, the periodicity of the circuit eliminates the need for the so called "golden wafer." The suggested algorithm has demonstrated the ability to detect defects of small area (0.023% of the image area). In addition, the algorithm was 93% successful in defect detection and has a false alarm rate of 0.067 per inspected frame, based on testing 20 frames.

This thesis discusses the application of the bond graph modeling technique directly coded into the Dynamic Modeling Language (DYMOLA) for simulating a solar-heated house. Scientists throughout the years have investigated the exploitation of solar radiation for space heating. In this thesis, the physical behavior of such a system is modeled and simulated in a convenient, robust and fast manner. The bond graph modeling methodology has found widespread use in a wide range of systems. DYMOLA is a modeling language well suited to represent bond graphs. DYMOLA is a program generator that can map a topological system description, such as a bond graph, into a state-space description expressed in the form of a DESIRE simulation program.

This thesis presents a procedure developed to study the effects of gain bandwidth on the magnitude performance of Leapfrog Filter Realizations. This procedure relies heavily on software developed for IBM compatible computers. Specific examples are carried out for second, third, and fourth order filter realizations. While this thesis deals solely with the magnitude characteristic of Leapfrog Filter realizations, the procedure itself is readily adapted to other applications such as magnitude, phase, or time domain performance of many different circuits.

Electro-Static Discharge (ESD) problems in the semiconductor industry are exacerbated by the lack of information about the magnitudes of these events and their locations. This thesis describes an integrated device, similar in structure to an EEP-ROM cell, capable of measuring the magnitudes and polarities of electrostatic discharges. A quantitative formulation of the transfer characteristic of the device as a function of the design parameters and the subsequent layout, manufacturing and evaluation of this detector was obtained. A chip was fabricated which included experiments to test the presented mathematical model and its extensive range of sensitivity, as well as several structures to evaluate the use of this detector in industrial environments. Extensive use of computers helped in the process design and in the simulation of the non-linear model for the operation.

We study the problem of acoustic wave propagation in a cylindrical borehole possessing a finite number of transverse discontinuities. We model the field behavior through Green's function techniques. We formulate an integral equation whose solution will enable us to solve for the acoustic field everywhere within our structure. We investigate asymptotic forms to speed the numerical convergence of our solution. To solve the integral equation we employ both the method of moments and the low frequency approximation. We study the reflection coefficient in the time and frequency domains. Finally after presenting solutions for the one and two fracture case, we generalize our analysis for many fractures.

The effects of ionizing radiation on the breakdown voltage of p-channel power MOSFETs were examined through two-dimensional simulation. The response of a reverse-biased n+-p junction to positive oxide-trapped charge, Not, is examined in detail, and analytical expressions for its characteristics are derived. These results provide insight into the breakdown performance of p-channel power MOSFETs in ionizing radiation environments, whose performance was found to be very different from corresponding n-channel power MOSFETs. Insights gained through analysis of p-channel devices suggest a termination/isolation scheme, the VLD-FRR, that will enhance p-channel device reliability in radiation environments. Two introductory chapters, which also serve as literature reviews, are provided. The buildup of Not in thick oxides and breakdown voltage of the power DMOS transistor are both reviewed, with attention focused on p-channel devices in both cases. Finally, suggestions for future work are given.