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)

With the increasing demand on wireless and portable devices, the radio frequency front end blocks are required to feature properties such as wideband, high frequency, multiple operating frequencies, low cost and compact size. However, the current radio frequency system blocks are designed by combining several individual frequency band blocks into one functional block, which increase the cost and size of devices. To address these issues, it is important to develop novel approaches to further advance the current design methodologies in both space and spectrum domains. In recent years, the concept of artificial materials has been proposed and studied intensively in RF/Microwave, Terahertz, and optical frequency range. It is a combination of conventional materials such as air, wood, metal and plastic. It can achieve the material properties that have not been found in nature. Therefore, the artificial material (i.e. meta-materials) provides design freedoms to control both the spectrum performance and geometrical structures of radio frequency front end blocks and other high frequency systems. In this dissertation, several artificial materials are proposed and designed by different methods, and their applications to different high frequency components and circuits are studied. First, quasi-conformal mapping (QCM) method is applied to design plasmonic wave-adapters and couplers working at the optical frequency range. Second, inverse QCM method is proposed to implement flattened Luneburg lens antennas and parabolic antennas in the microwave range. Third, a dual-band compact directional coupler is realized by applying artificial transmission lines. In addition, a fully symmetrical coupler with artificial lumped element structure is also implemented. Finally, a tunable on-chip inductor, compact CMOS transmission lines, and metamaterial-based interconnects are proposed using artificial metal structures. All the proposed designs are simulated in full-wave 3D electromagnetic solvers, and the measurement results agree well with the simulation results. These artificial material-based novel design methodologies pave the way toward next generation high frequency circuit, component, and system design.

In this dissertation, some multi-function and flexible RF/microwave devices have been studied to solve the issues in the modern microwave system designs. First, a power divider with two functions is proposed. The first function is a zero-phase delay power divider using zero-phase impedance transformer. The second function is a power divider with impedance transforming property. To achieve the first function, the two arms are treated as zero-phase impedance transformers. When the phase requirement is relaxed, the second function is obtained. Shunt transmission line stubs are employed to connect the isolation resistor, which provides great flexibility in the design. Then, a balun with transparent termination impedance and flexible open arms is designed. The design parameters of the balun are independent to the port impedance. This property allows the balun to work with different system impedances. Furthermore, the two output ports of the balun do not need to be connected together, which enables the device to have a very flexible structure. Finally, the continuous research of a tunable/reconfigurable coupler with equal output impedance is presented. In addition to the tunable/reconfigurable responses, unequal output impedance property is added to the microstrip line coupler. To shrink the size at the low frequency and make it easy for fabrication at higher frequency, the coupler is redesigned using lumped components. To validate the design theories, simulations are carried out. Moreover, prototypes of the power divider and the balun are fabricated and characterized. The simulation and measurement results match well with the theoretical calculation.