Digitized by Kansas Correctional Industries

Digitized by Kansas Correctional Industries

2 v. : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (D.E.)--Dept. of Electrical Engineering, University of Adelaide

Coplanar microstrip structures placed on dielectric substrates are used as high frequency electro-optic modulators. The method of lines, a mathematical technique for solving partial differential equations, has been applied to solve for the propagation characteristics of such a configuration. It has been determined that simple transmission line models are adequate to describe this system. The propagation characteristics are expressed in terms of the equivalent impedance and the phase velocity of the signal on the microstrip. In order to maximize the effective bandwidth of the modulator, the impedance is matched to that of the surrounding dielectric substrate, and the difference in the phase velocities of the two signals is minimized. The numerical technique developed here allows for the analysis of inhomogeneous dielectric substrates, so that trench structures for tuning the propagation characteristics to their desired values can be modelled. The numerical results for typical structures are presented, and suggest that the method of lines is a viable one for analyzing these modulator structures. / Graduation date: 1991

In this thesis a numerical technique to model general microstrip asymmetric and multiple step discontinuities is presented. The method is based on a magnetic wall waveguide model that is assumed to be valid for describing the electromagnetic fields associated with the microstrip line and in the vicinity of microstrip discontinuities. The fields are expanded in the uniform regions and the mode-matching method is applied at the discontinuities to analyze for the frequency dependent transmission properties of the multi ports. The generalized scattering matrix technique is used to model cascaded interacting discontinuities and is used to compute the properties of double-step and multi port structures. The generalized scattering matrix formulation takes into account the scattering phenomena of the dominant and all of the higher-order modes including evanescent ones. The validity of this model has been discussed extensively, and it is shown that the model can be used to describe the microstrip discontinuities with acceptable accuracy. The technique is applied (1) to study the transmission characteristics of asymmetric step discontinuities; (2) to design a filter for a desired frequency range using interacting asymmetric double step micros trip line; and (3) to design a new nominal 3db power devider of large bandwidth consisting of a three port rectangular patch. The techniques and models presented can be used in computer-aided analysis and design of such circuits. / Graduation date: 1993

Abstract The rolling is an efficient and economical approach for the manufacturing of strip or plate metals, it plays an important role because of its versatility and its high production rate in the manufacture of various products with uniform cross-sectional area. Without the knowledge of the influences of the variables such as friction conditions, material properties, and workpiece geometry on the process mechanics, it will not be possible to design and control the equipment adequately, or to predict and prevent the occurrence of failures. According to modeling by numerical has become a major tool in rolling research. By using the proper criterion, de-pending upon the production requirements along with the modeling results, the process efficiency, productivity and quality can be increased and the down time of the mill and cost operation can be reduced. In this study, investigated that it do not consider to work hardening and consider to work hardening during the rolling process from Von Karman theory. We can realize friction coefficient, reduction ratio, rolling force, rolling torque, neutral point, and pressure distribution relation, then from measuring rolling force, torque, neutral point can inverse to solve friction coefficient and pressure distribution. Result that we found the error of direct and inverse solution about rolling friction coefficient was less than 5 %, and the coef-ficient of friction was found to increase with reduction and rolling force and neutral point.

Thesis (M.S. in Systems Engineering (Electronic Warfare))--Naval Postgraduate School, September 1990. / Thesis Advisor(s): Atwater, Harry A. Second Reader: Janaswamy, Rama. "September 1990." Description based on title screen as viewed on December 29, 2009. DTIC Identifier(s): Suspended striplines, microstrip lines, equivalent circuits, program listings, theses. Author(s) subject terms: Suspended-microstrip line, step discontinuity, equivalent circuit model, step-change. Includes bibliographical references (p. 60). Also available in print.

Thesis (M.Phil.)--City University of Hong Kong, 2009. / "Submitted to Department of Electronic Engineering in partial fulfillment of the requirements for the degree of Master of Philosophy." Includes bibliographical references.

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains x, 64 p. : ill. (some col.), maps. Includes abstract. Includes bibliographical references (p. 63-64).

Thesis--Ph. D., University of Hong Kong, 1979.