Thesis (M.S.)--University of Akron, Dept. of Electrical Engineering, 2006. / "December, 2006." Title from electronic thesis title page (viewed 10/17/2007) Advisor, Nathan Ida; Committee members, James Grover, George C. Giakos; Department Chair, J. Alexis De Abreu Garcia; Dean of the College, George K. Haritos; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.

Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2009 / This thesis presents the design, analysis and implementation of an eight-element phased array antenna for wideband X-band applications. The microstrip phased array antenna is designed using eight quasi-Yagi antennas in a linear configuration and is printed on RT/Duroid 6010LM substrate made by Rogers Corporation. The feeding network entails a uniform beamforming network as well as a non-uniform -25 dB Dolph-Tschebyscheff beamforming network, each with and without 45° delay lines, generating a squinted beam 14° from boresight. Antenna parameters such as gain, radiation patterns and impedance bandwidth (BW) are investigated in the single element as well as the array environment. Mutual coupling between the elements in the array is also predicted. The quasi-Yagi radiator employed as radiating element in the array measured an exceptional impedance bandwidth (BW) of 50% for a S11 < -10 dB from 6 GHz to 14 GHz, with 3 dB to 5 dB of absolute gain in the frequency range from 8 GHz to 11.5 GHz. The uniform broadside array measured an impedance BW of 20% over the frequency band and a gain between 9 dB to 11 dB, whereas the non-uniform broadside array measured a gain of 9 dB to 11 dB and an impedance BW of 14.5%. Radiation patterns are stable across the X-band. Beam scanning is illustrated in the E-plane for the uniform array as well as for the non-uniform array.

This dissertation investigates a simple LC-matching network for the impedance bandwidth enhancement of microstrip patch antennas. Wideband impedance matching is a standard practice for active circuits. Simple impedance matching of antennas is also quite common, but data on wideband impedance matching of antennas is not found very much in the open literature. The matching circuit presented consists out of a resonant LC-circuit with a quarterwave matching line as part of the design. Results for a number or experimental antennas, on which the new technique was applied, are included in the report. A well-defined design procedure is also presented, and results in a relatively small circuit to implement. It is shown that the antenna VSWR bandwidth could be improved to more than double the original size in most of the antennas investigated. / Dissertation (M Eng (Electronic Engineering))--University of Pretoria, 2006. / Electrical, Electronic and Computer Engineering / unrestricted

Thesis: Elec. E., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 1980 / Bibliography: leaf 96. / by Jeffrey Clay McHarg. / Elec. E. / Elec. E. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science

This thesis investigates the presence of multiple (quasi-TEM) modes in inverted embedded microstrip lines. It has already been shown that parasitic modes do exist in inverted embedded microstrips due to field leakage inside the dielectric substrate, especially for high dielectric constants (like Silicon). This thesis expands upon that work and characterizes those modes for a variety of geometrical dimensions. Chapter 1 focuses on the theory behind the different transmission line modes, which may be present in inverted embedded microstrips. Based on the structure of the inverted embedded microstrip, the conventional microstrip mode, the quasi-conventional microstrip mode, and the stripline mode are expected. Chapter 2 discusses in detail the techniques used to decompose the total probed field into the various modes present in the inverted embedded microstrip lines. Firstly, a short explanation of the finite-difference time-domain method, that is used for the simulation and modeling of inverted microstrips up to 50 GHz is provided. Next, a flowchart of the process involved in decomposing the modes is laid out. Lastly, the challenges of this approach are also highlighted to give an appreciation of the difficulty in obtaining accurate results. Chapter 3 shows the results (dispersion diagrams, values/percentage of the individual mode energies ) obtained after running time-domain simulations for a variety of geometrical dimensions. Chapter 4 concludes the thesis by explaining the results in terms of the transmission line theory presented in Chapter 1. Next, possible future work is mentioned.

Layered multiconductor coupled slot and strip-slot structures are characterized by introducing the full-wave modal analysis as well as the quasi-TEM spectral domain technique. In the modal analysis, the electric and magnetic fields are constructed in terms of modal fields in different regions. Application of the boundary conditions at interfaces for the tangential components of the electric and magnetic fields results in the dyadic Green's function, which interrelates the tangential currents and electric fields at the boundaries of the layered structure. The slot fields and strip currents are expanded in terms of a set of known basis functions with unknown coefficients. Use of the Galerkin method leads to a set of algebraic equations. The non-trivial solutions for the propagation constants are found by setting the determinant of the algebraic equations equal to zero. All the other normal mode parameters including the modal impedances, the field and current eigenvectors are then computed by using the solutions of the propagation constants. In the quasi-TEM analysis, the Laplace equation is transformed to an ordinary differential equation in the spectral domain, the solution of which together with the boundary conditions yields the Green's function which interrelates the potential and the charge distribution at the interfaces of the layered structure. The charge distribution is expanded in terms of known functions with unknown coefficients which are subsequently evaluated by applying the Galerkin method. Once the charge distribution is found, the quasi-TEM characteristics of the coupled strip-slot structures are readily calculated. Different impedance definitions proposed in the literature for multiple coupled line structures are discussed. The only useful impedance definition in the design of microwave and millimeter-wave circuits is the one that results in a symmetric impedance matrix for a coupled line structure in a lossless, isotropic, and linear medium. The normal mode impedance definition as based on the reciprocity is used to systematically study the impedance characteristics of various coupled slot structures for the first time, which together with the propagation characteristics are used to compute equivalent circuit models for ideal coupled line structures. The applications of the coupled slot and strip-slot structures are illustrated through design examples of enhanced couplers and power dividers consisting of coupled line multiports. Time domain simulation of coupled multiconductor structures with slotted ground planes is also presented to exemplify the applications of the techniques developed in this thesis to layered interconnects and packaging structures in high-speed circuits. Some novel techniques to reduce the crosstalk noise in those structures are proposed with theoretical examples and experimental results. / Graduation date: 1994

Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 26, 2007) Includes bibliographical references (p. 112-113).

Thesis (M. Eng.)--Carleton University, 2001. / Includes bibliographical references (p. 189-193). Also available in electronic format on the Internet.

Please read the abstract (Summary) in the section 00front of this document / Dissertation (MEng (Electronic Engineering))--University of Pretoria, 2007. / Electrical, Electronic and Computer Engineering / MEng / Unrestricted

The thesis represents the design for dual-band quarter wavelength and half wavelength microstrip transmission line. Chapter 2 proposed the design of a novel dual-band asymmetric pi-shaped short-circuited quarter wavelength microstrip transmission line working at frequencies 1GHz and 1.55 GHz for 50Ω transmission line and at frequencies 1GHz and 1.43GHz for 60Ω transmission line. Chapter 3 proposed the design of a novel dual-band quarter wavelength microstrip transmission line with asymmetrically allocated open stubs and short-circuited stubs working at frequencies 1GHz and 1.32GHz. Chapter 4 proposed the design of dual-band pi-shaped open stub half wavelength microstrip transmission line working at frequencies 1GHz and 2.07GHz. Numerical simulations are performed both in HyperLynx 3D EM and in circuit simulator ADS for all of the proposed designs to measure the return loss (S11) and insertion loss (S12) in dB and phase response for S12 in degree.