Browsing Doctoral Degrees (Electrical and Electronic Engineering) by Title

Now showing items 80-99 of 130

    • Magnetic modelling, analysis and on-chip shielding of SFQ Circuits 

      Bakolo, Simeon Rodwell (Stellenbosch : Stellenbosch University, 2018-03)
      ENGLISH ABSTRACT: Single Flux Quantum (SFQ) based electronic circuits are susceptible to failure if exposed to external magnetic fields, even in very small quantities. Operating margins of SFQ circuits have shown to decrease ...

    • The measurement of radio frequency complex permeability of thin round wires 

      Stuart, Thomas (Thomas Edward Walter) (Stellenbosch : Stellenbosch University, 2003-04)
      ENGLISH ABSTRACT: This thesis is concerned with the measurement of the complex permeability of thin round wires at radio frequencies. This is of interest as such wires are used in various applications, such as absorbing ...

    • Measuring, refining and calibrating speaker and language information extracted from speech 

      Brummer, Niko (Stellenbosch : University of Stellenbosch, 2010-12)
      ENGLISH ABSTRACT: We propose a new methodology, based on proper scoring rules, for the evaluation of the goodness of pattern recognizers with probabilistic outputs. The recognizers of interest take an input, known to ...

    • The method of manufactured solutions for the verification of computational electromagnetic codes 

      Marchand, Renier Gustav (Stellenbosch : Stellenbosch University, 2013-03)
      ENGLISH ABSTRACT: In this work the Method of Manufactured Solutions (MMS) is introduced for the code veri cation of full-wave frequency dependent electromagnetic computational software. At rst the method is sketched ...

    • Methods to quantify and reduce rotor losses in a solid rotor yoke permanent magnet machine 

      Wills, Dominic (Stellenbosch : University of Stellenbosch, 2010-03)
      ENGLISH ABSTRACT: Certain types of electric machines are particularly susceptible to the proliferation of eddy currents flowing within the solid conducting regions in the rotor. Single-layer, non-overlapping windings ...

    • Microwave dielectric heating through interference modulation with narrow band high power sources 

      Meier, Ingolf (Stellenbosch : Stellenbosch University, 2002-12)
      ENGLISH ABSTRACT: One of the most difficult problems in microwave dielectric heating is the generation and control of field and heating patterns. A technique allowing the synthesis of different, pre-determinable heating ...

    • Miniaturised multilayer RF and microwave Circuits 

      Nassar, Shamim Omar (Stellenbosch : Stellenbosch University, 2016-03)
      ENGLISH ABSTRACT: Ceramic and laminate multilayered technologies are explored in the design of novel circuit topologies and in novel implementations of classical circuit topologies. A cross-slot coupled filter topology ...

    • Modal-based design techniques for circular quadruple-ridged flared horn antennas 

      Beukman, Theunis Steyn (Stellenbosch : Stellenbosch University, 2015-03)
      ENGLISH ABSTRACT: This dissertation presents modal-based techniques for the effective systematic design of quadruple-ridged flared horns (QRFHs) as reflector feeds for radio astronomy applications. A new excitation ...

    • Modelling and mitigation of specular multipath interference in a dual-frequency phase comparison FMCW radar system 

      Schonken, Willem Petrus Francois (Stellenbosch : Stellenbosch University, 2017-03)
      ENGLISH ABSTRACT: Digital signal processing technology has improved greatly over the last two decades. Increased processing power, cheaper memory and higher sampling rates have enabled the application of Frequency-Modulated ...

    • Modelling of Antenna Responses 

      Mutonkole, Ngoy (Stellenbosch : Stellenbosch University, 2016-12)
      ENGLISH ABSTRACT: This dissertation presents surrogate modelling techniques for the radiation patterns and scattering parameters of antennas. The models are developed in the context of calibration of re ector antennas ...

    • Modelling, estimation and compensation of imbalances in quadrature transceivers 

      De Witt, Josias Jacobus (Stellenbosch : University of Stellenbosch, 2011-03)
      ENGLISH ABSTRACT: The use of the quadrature mixing topology has been severely limited in the past due to its sensitivity towards mismatches between its signal paths. In recent years, researchers have suggested that digital ...

    • Multi-bias decomposition-based optimisation for the extraction of small-signal GaAs FET models 

      Van Niekerk, Cornell (Stellenbosch : Stellenbosch University, 1999-07)
      ENGLISH ABSTRACT: The availability of accurate nonlinear models is essential for the accurate and cost effective design of high frequency telecommunication systems. A key step in the creation of such models is the ...

    • Multi-mode antennas for hemispherical field-of-view coverage 

      Prinsloo, David Schalk Van der Merwe (Stellenbosch : Stellenbosch University, 2015-03)
      ENGLISH ABSTRACT: This dissertation proposes a multi-mode antenna element excited through a multiconductor feed. It is shown that each of the orthogonal transverse electromagnetic modes supported by the antenna feed ...

    • Natural balancing mechanisms in converters 

      Van der Merwe, Johannes Wilhelm (Wim) (Stellenbosch : University of Stellenbosch, 2011-03)
      AFRIKAANSE OPSOMMING: Hierdie proefskrif handel oor die natuurlike balanserings meganismes van veelvlakkige en modulêre omsetters wat fase-skuif dragolf puls wydte modulasie gebruik. Die meganismes kan in twee hoof groepe ...

    • Natural balancing of multicell converters 

      Wilkinson, Richardt Howard (Stellenbosch : University of Stellenbosch, 2004-04)
      ENGLISH ABSTRACT: Multilevel converters were developed as a result of a growing need for higher power converters. This dissertation addresses a specific multilevel topology called the multicell topology. A problem associated ...

    • Natural balancing of three-phase 2-cell and 3-cell multicell converters 

      Salagae, Isaac Mahijoko (Stellenbosch : University of Stellenbosch, 2010-03)
      ENGLISH ABSTRACT: The multicell inverter, being a widely used multilevel converter, has received much attention in recent years due to problems associated with cell capacitor voltage. In this dissertation we study the ...

    • The non-destructive measurement of the radio frequency properties of hard rock borehole cores 

      Rutschlin, Marc (Stellenbosch : Stellenbosch University, 2005)
      ENGLISH ABSTRACT: The effective use of borehole radar in geophysical exploration requires accurate knowledge of the dielectric properties of the geological system in which it is employed. The attenuation and propagation ...

    • Novel direct field and torque control of six-phase induction machine with special phase current waveform 

      Ai, Yong-le (Stellenbosch : University of Stellenbosch, 2006-12)
      This study focuses on the drive control system of a novel direct field and torque current control applied to a six-phase induction motor. Special phase current waveforms that make it possible to have separate field and ...

    • On-board image quality assessment for a satellite 

      Marais, Izak van Zyl (Stellenbosch : University of Stellenbosch, 2009-03)
      The downloading of images is a bottleneck in the image acquisition chain for low earth orbit, remote sensing satellites. An on-board image quality assessment system could optimise use of available downlink time by ...

    • Optimal topology and critical evaluation of slip synchronous permanent magnet wind generator 

      Potgieter, Johannes Hendrik Jacob (Stellenbosch : Stellenbosch University, 2014-04)
      ENGLISH ABSTRACT: In this study the recently proposed slip-synchronous permanent magnet generator (SS-PMG), is considered as an alternative to other wind generator topologies. The SS-PMG is connected directly to the grid ...