Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 134-141). Also available in electronic version.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references. Also available in electronic version.

Thesis (M.S.) -- Brigham Young University. Dept. of Electrical and Computer Engineering, 2002. / Includes bibliographical references (p. 99-103).

Relative sensitivity is a measure of the percentage change in a system parameter caused by a percentage change in a component parameter. The adjoint network method has previously been used by Monaco and Tiberio in the computation of relative scattering parameter sensitivity. A new approach is presented in this work which defines a bilinear equation and three constants that relate any component scattering parameter to any system scattering parameter. A computer-aided design program which implements this relative sensitivity in analysis and optimization is presented. Circuit analysis examples demonstrating sensitivity analysis and optimization are included. As a background for this work, computer-aided design concepts, such as network modeling, objective functions, Rosenbrock's optimization method, and the adjoint network method for estimating partial derivatives, are also presented. / Master of Science

An efficient integral equation method based on a method of moment (MoM) discretization of the Mixed-Potential Integral Equation (MPIE) for the analysis of 2.5D or 3D planar microwave circuits is presented. The robust Discrete Complex Image Method (DCIM) is employed to approximate the Greens functions in layered media for horizontal and vertical sources of fields, where closed-form formulations of the z-integrations are derived in the spectral domain. Meanwhile, an efficient and accurate numerical integration technique based on the Khayat-Wilton transform is used to integrate functions with 1/R singularities and near singularities. The fast iterative solver - Quadrature Sampled Pre-Corrected Fast Fourier Transform (QSPCFFT) - is associated with the MoM formulation to analyze electrically large, dense and complex microwave circuits.

There has been unprecedented growth in wireless technologies in recent years; wireless devices such as cellular telephones and wireless local area network (WLAN) transceivers are becoming ubiquitous. It is now common for a single hardware device, such as a cellular telephone, to be capable of multi-band operation. Implementing a dedicated radio frequency (RF) front-end for each frequency band increases the component count and therefore the cost of the device. Consequently, there is now a requirement to design RF and microwave circuits that can be reconfigured to operate at different frequency bands, as opposed to switching between several fixed-frequency circuits. Barium strontium titanate (BST) thin films show great promise for application in reconfigurable microwave circuits. The material has a high dielectric constant which can be controlled by the application of a quasi-static electric field, combined with relatively low losses at microwave frequencies. Tunable microwave components based on BST-thin films have the potential to replace several fixed components, thereby achieving useful size and cost reductions. This thesis is concerned with the growth and microwave circuit applications of BST thin films on c- and r-plane sapphire substrates. Sapphire is an ideal substrate for microwave integrated circuit fabrication due to its low cost and low loss. Electronically tunable capacitors (varactors) were fabricated by patterning interdigital electrode structures on top of the BST films. High capacitance tunabilities of 56% and 64% were achieved for the films grown on c-plane and r-plane sapphire, respectively, at 40 V bias. A novel electronically tunable 3 dB quadrature hybrid circuit was also developed. Prototypes of this circuit were initially implemented using commercial varactor diodes, in order to validate the design. An integrated version of the coupler was then fabricated using BST varactors on c-plane sapphire. The results achieved demonstrate the potential of sapphire-based BST thin films in practical microwave circuits.

Thesis (Ph.D.)--McMaster University, 2005. / Supervisor: N.K. Nikolova and M.H. Bakr. Includes bibliographical references (leaves 134-141). Mode of access:World Wide Web.

Numerical methods are very important in the areas of microwave and RF engineering, antenna design, bio-electromagnetics, electromagnetic compatibility and interference (EMC/EMI). Among several techniques, time domain methods such as the Finite Difference Time Domain (FDTD) method and the Transmission Line Matrix (TLM) method are of particular interest, due to their high flexibility and ease of implementation, given the powerful computation resource available. This dissertation is focused on the TLM method, a discrete time evolution scheme, based on the analogy between the discretized electromagnetic field and a mesh of transmission lines. Generally, in a numerical method, much effort is spent on reducing the computational burden, increasing the ability and flexibility to handle hybrid problems and to model various properties of materials. The objective of the proposed research is to a) develop, implement, and test several techniques aimed at enhancing the accuracy of time domain analysis of microwave and high speed circuits without increasing the computational load, b) to develop methods to embed circuits and devices into a field environment or to import field analysis into a circuit simulator, and c) enhance the modeling of a wide range of materials, including metamaterials with negative refractive index, and magnetized ferrites. By making good use of these techniques it is possible to incorporate more information into the TLM solution, thus enabling more accurate, more efficient and more powerful CAD tools for industry and academia.

Thesis (M. App. Sc.)--Carleton University, 2001. / Includes bibliographical references (p. 91-102). Also available in electronic format on the Internet.

Thesis (Ph. D.)--Carleton University, 2003. / Includes bibliographical references (p. 162-169). Also available in electronic format on the Internet.