Thesis (M. App. Sc.)--Carleton University, 2003. / Includes bibliographical references (p. 85-92). Also available in electronic format on the Internet.

Thesis (M. App. Sc.)--Carleton University, 2004. / Includes bibliographical references (p. 95-104). Also available in electronic format on the Internet.

Thesis (Ph. D.)--Carleton University, 2004. / Includes bibliographical references (p. 156-176). Also available in electronic format on the Internet.

Thesis (M.App.Sc.) - Carleton University, 2006. / Includes bibliographical references (p. 103-107). Also available in electronic format on the Internet.

Thesis (Ph.D.). / Written for the Dept. of Electrical & Computer Engineering. Title from title page of PDF (viewed 2009/06/10). Includes bibliographical references.

Thesis (MScEng)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: The topic of microwave frequency discriminators is introduced. Various applications and implementation techniques of these devices are given and discussed. This thesis may serve as reference foundation for future research on this topic. Discriminators are developed at both S- and X-band, with high linearity and good sensitivity. The systems used to implement these devices are developed as well. The S-band discriminator is used in a direct FM demodulation system, which works well. / AFRIKAANSE OPSOMMING: Hierdie is 'n inleiding tot die onderwerp van mikrogolf frekwensie diskrimineerders. Verskeie toepassings en implementeringstegnieke van hierdie toestelle word genoem en bespreek. Hierdie tesis kan dien as verwysings-raamwerk vir toekomstige navorsing oor hierdie onderwerp. Diskrimineerders is ontwikkel by beide S- en X-band, met 'n goeie lineariteit en sensitiwiteit. Die stelsels wat gebruik word om hulle te implementeer, is ook ontwikkel. Die S-band diskrimineerder is gebruik in 'n direkte FM demodulasie sisteem en werk goed.

Thesis (MScEng)--University of Stellenbosch, 2001. / ENGLISH ABSTRACT: The application of artificial neural networks to microwave circuits is investigated. A neural network model is developed for two parallel waveguides coupled by a longitudinal slot in the common broad wall. Training data is generated through a moment method solution of the integral equations that describe the structure. A systematic investigation of training options is carried out and the development of the model is described in detail. The model is evaluated and compared with an Adaptive Sampling Interpolation (ASI) Technique. The neural network is found to be less accurate than the ASI Technique at a much greater expense of development time and required user supervision. / AFRIKAANSE OPSOMMING: Die toepassing van neurale netwerke op mikrogolfbane is ondersoek. In Neurale netwerk-model is ontwikkel vir twee parallelle golfleiers met longitudinale gleufkoppeling in die gemeenskaplike bree wand. Data vir die opleiding van die netwerke is verkry deur In momentmetode-oplossing van die integraalvergelykings wat die struktuur beskryf. Verskillende ontwerpsopsies vir die netwerke is stelselmatig ondersoek en die ontwikkelingsproses van die netwerk is volledig beskryf. Die model is geevalueer en vergelyk met In Aanpasbare Monstering Interpolasietegniek (AMI). Daar is gevind dat die neurale netwerk minder akkuraat is as die AMI terwyl die koste aan ontwikkelingstyd en gebruikerstoesig hoer is.

This thesis contributes to the development of tuning space mapping (TSM) for computer-aided design and optimization of microwave circuits. Tuning space mapping applies the traditional engineering tuning idea into the realm of space mapping. It takes advantage of both the efficiency of space mapping and the expertise required for tuning of engineering devices. We present the state of the art in tuning space mapping and selected applications, and discuss how it relates to regular space mapping. A TSM algorithm is illustrated and implemented. Tuning space mapping shifts the burden of optimization from expensive electromagnetic (EM) models to cheap and fast tuning models. Meanwhile, design accuracy is achieved by keeping the EM simulation result in an S-parameter file in the circuit simulator, while performing optimization only on certain circuit theory-based components that are introduced into the tuning model. One important step in this tuning approach is to translate the tuning parameters to adjustments in the design parameters. Up to now, this was implemented by experience. Scarcely any systematic algorithm was suggested. In this thesis, we introduce a systematic "calibration" process which aims at calibrating the EM dimensions by the optimizable tuning parameters. Several calibration methods can accomplish this translation process. They are demonstrated here by applications. / Thesis / Master of Applied Science (MASc)

No description available.

<p> This thesis contributes to the development of adjoint variable methods (AVM) and space mapping (SM) technology for computer-aided electromagnetics (EM)-based modeling and design of microwave circuits and antennas.</p> <p> The AVM is known as an efficient approach to design sensitivity analysis for problems of high complexity. We propose a general self-adjoint approach to the sensitivity analysis of network parameters for an Method of Moments (MoM) solver. It requires neither an adjoint problem nor analytical system matrix derivatives. For the first time, we suggest practical and fast sensitivity solutions realized entirely outside the EM solver, which simplifies the implementation. We discuss: (1) features of commercial EM solvers which allow the user to compute network parameters and their sensitivities through a single full-wave simulation; (2) the accuracy of the computed derivatives; (3) the overhead of the sensitivity computation. Our approach is demonstrated by FEKO, which employs an MoM solver.</p> <p> One motivation for sensitivity analysis is gradient-based optimization. The sensitivity evaluation providing the Jacobian is a bottleneck of optimization with full-wave simulators. We propose an approach, which employs the self-adjoint sensitivity analysis of network parameters and Broyden's update for practical EM design optimization. The Broyden's update is carried out at the system matrix level, so that the computational overhead of the Jacobian is negligible while the accuracy is acceptable for optimization. To improve the robustness of the Broyden update in the sensitivity analysis, we propose a switching criterion between the Broyden and the finite-difference estimation of the system matrix derivatives.</p> <p> In the second part, we apply for the first time a space mapping technique to antenna design. We exploit a coarse mesh MoM solver as the coarse model and align it with the fine mesh MoM solution through space mapping. Two SM plans are employed: I. implicit SM and output SM, and II. input SM and output SM. A novel local meshing method is proposed to avoid inconsistencies in the coarse model. The proposed techniques are implemented through the new user-friendly SMF system. In a double annular ring antenna example, the S-parameter is optimized. The finite ground size effect for the MoM is efficiently solved by SM Plan I and the design specification is satisfied after only three iterations. In a patch antenna example, we optimize the impedance through both plans. Comparisons are made. Coarseness in the coarse model and its effect on the SM performance is also discussed.</p> / Thesis / Master of Applied Science (MASc)