The advent of Substrate Integrated Circuit (SIC) technology, and specifically Substrate Integrated Waveguide (SIW) technology has made it feasible to design and fabricate low loss and high quality factor (Q-factor) microwave and millimeter wave structures on a compact and integrable layout and at a low cost. The SIW structure is the planar realization of the conventional rectangular waveguide (RWG). In this technology, the side walls of the waveguide are replaced with two rows of metallic vias, which are connecting two conductor sheets, located at the top and bottom of a dielectric slab. The motivation for this thesis has been to develop an analytical method to efficiently analyze SIW structures, and also design different types of passive microwave components based on this technology. As SIW structures are imitating waveguide structures in a planar format, the field distributions inside these structures are very close to those in waveguides. However, due to the very small substrate height in conventional planar technologies, and also the existence of a row of vias, instead of a solid metallic wall, there is a reduced set of modes in SIW compared to regular waveguide. This fact has given us an opportunity to deploy efficient modal analysis techniques to analyze these structures. In this thesis, we present a Mode Matching Techniques (MMT) approach for the analysis of H-plane SIW structures. One of the areas of application, which can significantly benefit from having an efficient analytical method, is designing and optimizing new circuits. Having such an analytical tool, which is faster than commercially available field solvers by an order of magnitude, new components can be designed, analyzed and optimized in a fast and inexpensive manner. Based on this technique, various types of passive microwave components including filters, diplexers, power dividers and couplers, some of which are among the first to be reported in SIW technology, are designed and analyzed in this thesis. Also based on this technique, the most accurate formula for the effective waveguide width of the SIW is presented in this thesis. In order to provide means to excite and measure SIW components, transitions between these structures and other planar topologies like microstrip and coplanar waveguide (CPW) are needed. More importantly, low-reflection transitions to microstrip are required to integrate SIW circuits with active components, and therefore it is vital to provide low-reflection transitions so that the component design is independent of the influences of the transitions. In this thesis, a new wideband microstrip-to-SIW transition, with the lowest reported reflection coefficient, is also introduced. / Graduate / 0544 / zkordi@ece.uvic.ca

[pt] Este trabalho apresenta um estudo abrangente sobre novas técnicas para modelagem de sensores eletromagnéticos usados na prospecção de petróleo. Estes sensores normalmente ficam imersos em formações geofísicas complexas (não homogêneas, dissipativas e anisotrópicas) com dimensões e parâmetros constitutivos do meio envolvendo múltiplas escalas, e isso representa um problema desafiador para as técnicas tradicionais de eletromagnetismo computacional. Nossa proposta supera esses problemas e contribui para uma melhor compreensão dos fenômenos eletromagnéticos físicos que ocorrem nessas estruturas. Analisamos o problema de propagação usando: a) uma técnica de onda completa baseada no método de casamento de modos, b) soluções perturbacionais para a equação integral de Fredholm vetorial baseadas na aproximação de Born, e c) métodos variacionais para o cálculo da impedância dos sensores eletromagnéticos de interesse para a exploração geofísica. Nós apresentamos resultados que demostram a capacidade das técnicas introduzidas nesta tese para modelar de forma acurada e eficiente sensores eletromagnéticos de forma mais realista do que as alternativas disponiveis na literatura. O custo computacional dos algoritmos desenvolvidos é relativamente baixo comparado com técnicas puramente numéricas tradicionais (tais como os métodos de elementos e diferenças finitas ou o método dos momentos). / [en] This work presents a comprehensive study on some techniques for modeling electromagnetic sensors used in well prospecting. These sensors are usually immersed in complex geophysical formations (inhomogeneous, dissipative, and anisotropic) with multiscale dimensions and constitutive parameters of the medium abruptly varying, resulting in a challenging problem for conventional computational electromagnetic techniques. Our proposal overcomes these problems and contributes to a better understanding of the physical electromagnetic phenomena that occur in these structures. We analyzed the propagation problem by using: a) a fullwave method based on the mode-matching technique, b) perturbational solutions for solving a Fredholm integral equation on the grounds of the Born approximation, and c) variational methods for calculating the sensor impedance. We present results that demonstrate the ability of the techniques introduced in this dissertation to accurately and efficiently modeling electromagnetic sensors in a more realistic fashion when compared with other methods available in the literature.The computational cost of the numerical algorithms developed in this work is relatively low if compared to that required in traditional techniques (such as finite elements, finite differences, and method of moments).