A uniplanar balun that transforms unbalanced coplanar waveguide (CPW) to balanced coplanar strip line (CPS) is characterised through simulation and measurement. By illustrating the effect of many of the critical design parameters, the operation of this balun is discussed and a set of design criteria is defined. The parameter study discusses the size and shape of the radial open, the type and length of the CPW taper and the thickness and type of the bond wires. Newly developed etched bond wires are implemented to provide better manufacturing repeatability and reliability. A complete balun testing procedure is developed and described, consisting of three separate tests. The balun is tested in the normal back-to-back configuration, as a terminated single balun, and the magnitude and phase imbalance is also determined by using a three-port test circuit connected to the balun. The advantages of implementing this full test procedure, and thus fully characterising the balun under test, are emphasised throughout. Results obtained by using this procedure show that the basic balun works well over the full operating band, except for the phase imbalance, which is usable but not optimal. A simple technique to correct the phase imbalance of the balun is introduced, and validated through measurements of the balun connected to the three-port test circuit. As a final validation the balun is connected as feed for an etched dipole antenna for which good impedance matching and pattern results are shown. AFRIKAANS : ’n Enkelvlak balon (BALans-na-ONbalans) wat van ongebalanseerde enkelvlak golfgeleier (CPW) na gebalanseerde enkelvlak strooklyn (CPS) transformeer, word gekarakteriseer deur simulasie en metings. Deur die effek van baie van die kritiese ontwerpsparameters te demonstreer, word die werking van die balon bespreek en ’n stel ontwerpskriteria opgestel. Die parameter studie bespreek die radiale ope struktuur se vorm en grote, die tipe en lengte van die CPW transformator and die dikte en tipe van die konneksie drade. Nuut ontwikkelde geëtste konneksie drade word geïmplementeer om beter vervaardigingsherhaalbaarheid en betroubaarheid te verseker. ’n Volledige balon toetsprosedure word ontwikkel en beskryf en bestaan uit drie aparte toetse. Die balon word getoets in die normale rug-aan-rug konfigurasie, as ’n enkel getermineerde balon en die grote asook fase van die wanbalans word bepaal deur die gebruik van ’n drie-poort toetsbaan wat aan die balon gekoppel word. Die voordele verbonde daaraan om hierdie volledige toetsprosedure toe te pas, en daardeur die balon volledig te karakteriseer, word deurlopend beklemtoon. Die resultate wat hierdie prosedure oplewer wys dat die basiese balon goed werk oor die volledige frekwensieband, behalwe vir die fase-wanbalans parameter, wat bruikbaar, maar nie ideaal is nie. ’n Eenvoudige tegniek om die fase-wanbalans van die balon te korrigeer word bekend gestel en getoets deur die drie-poort toetsbaan weer te gebruik. As ’n finale validasie word die balon aan ’n geëtste dipool gekoppel word, waarvan goeie impedansie aanpassings en patrone gewys word. Copyright / Dissertation (MEng)--University of Pretoria, 2010. / Electrical, Electronic and Computer Engineering / unrestricted

Text in English, with abstracts and keywords in English, Sesotho and Afrikaans / The purpose of the study was to investigate and explore how rehabilitation and wellness of juvenile offenders in selected South African correctional schools can be promoted. A wellness model that can be used to promote the wellness of juvenile offenders was proposed based on the findings of the study. The researcher used the wellness, ubuntu and bio-ecological theories as theoretical frameworks to guide the study. These theories helped the researcher to understand how the promotion of wellness among juvenile offenders can facilitate effective rehabilitation and, ultimately, offender reintegration into society. The interpretive paradigm was employed to understand the experiences and views of juveniles as well as teachers and heads of schools who were directly involved in the rehabilitation of juvenile offenders. The study used the qualitative research method in which open-ended questionnaires were used to collect data from juveniles and teachers whereas semi-structured interviews were to collect data from heads of schools. Participants were purposefully selected to ensure relevant data was gathered. Twenty-one juveniles, twelve teachers and seven heads of schools took part in the study. Participants were drawn from four provinces and seven schools. Data were analysed qualitatively through coding, categorising and developing themes. Themes that developed from data interpretation were used as headings for the findings in each wellness dimension. Themes that developed from the study revealed that schools were making a great effort to promote the wellness of juvenile offenders. Great strides were made especially in promoting the wellness of juvenile offenders through the involvement of different stakeholders although this was inadequate. Schools were facing challenges such as lack of resources, shortage of skilled personnel as well as inadequate stakeholder involvement. The research proposed a wellness model that is holistic in nature to help teachers and other stakeholders involved in juvenile offender rehabilitation to promote their social, physical, emotional, spiritual, career and intellectual wellness. / Mohola wago bala e be e le go aga lenaneo leo le ka šomišwago ke barutisi le batho ba bangwe mo thekgong ya bana bao ba lego dikolong tsa kgolego (dihlokatsebe). Lenaneo le mohola wa lona ke go dira gore bana ba ba sa hlokomeleng melao ya setšhaba ba bušetšwe gore ba kgone go boela go setšhaba. Basekaseki ba šomiša go hlokomela botho le tša tlhago go tlhatlha dithuto tša bona. Dikakanyo tse di dirišeditšwe go dihloka tsebe le barutiši le dihlogo tša dikolo bao ba bego ba ruta bana ba. Thuto ye e šomišitšwe ke ya maemo a godimo moo go šomišitšwego dipotšišo tšeo di se nago phetolo e tee go hwetša kakanyo ya dihlokatsebe le barutiši. Fela mo gongwe go be go dirišwa dipotšišo go dihlogo tsa sekolo. Bao ba bego ba botšišwa ba be ba kgethilwe gabotse goba go lekaleka gore dikarabo e be tša maleba. Masomepedi a dihlokatsebe, barutiši bašupa le dihlogo tsa sekolo ba ile ba šomišwa go dithuto tše. Bao ba kgethilwego ba be ba tšwa di provensing tše nne le dikolong tše šupa tša kgolego. Dikašišo di ile tša sekasekwa gabotse ka maemo a godimo go šomišwa dinomoro, peakanyo le gore ba kgone go aga maikemišetšo a motheo wo. Motheo wo o agilwe go tšwa go dikakišišo gore re hwetše hlokomelo ya dihlokatsebe. Metheo ye e šomišitšwego e bontšhitse gore dikolong tša dihlokatsebe bana ba be ba latela molao. Gobe go šomišwa le kago ya mmele, go tsošološwa moyeng ya di hlokatsebe go šomišwa batho kamoka. Dikolo di ile tša ba le bothata mo go godišeng dihlokatsebe. Yengwe ya bothata e be e le go hlokega ga dišomišwa le batho bao ba hlahlilwego go ruta dihlokatsebe tše mola gape go be go se na batho bao ba nago le kgahlego. Basekaseki ba ile ba tla le seka sa go hlokomela dihlokatsebe ka go felela le go thuša barutiši le batho bao ba lebanego le dihlokatsebe. Gore go godišwe kgwerano, go godišwe go aga ga mmele, go aga tsošološo ya semoya, go ba aga gore ba be le seo ba kgonago le go aga le go godiša menagano ya bona le tša mešomo. / Die doel van die studie was om ’n welstandsmodel te ontwikkel wat gebruik kan word deur onderwysers en relevante belanghebbendes in die bevordering van die welstand van jeugdige oortreders in korrektiewe skole. Die model beoog om te verseker dat jeugdige oortreders doelftreffend gerehabiliteer word en gereed is vir herintegrering in die samelewing. Die navorser het die welstand, ubuntu en bio-ekologiese teorieë as teoretiese raamwerke gebruik om die studie te lei. Hierdie teorieë het die navorser gehelp om te verstaan het die promosie van welstand onder jeugdige oortreders doeltreffende rehabilitasie kan fasiliteer en uiteindelik, oortreders in die samelewing te herstel. Die uitleggende paradigma is aangewend in ’n poging om die ervarings en sienings van die jeugdiges, onderwysers en hoofde van skole wie direk betrokke in die rehabilitasie van jeugdige oortreders is te verstaan. Die studie maak gebruik van die kwalitatiewe navorsings-benadering, waar ope vrae gebruik is om data van jeugdiges en onderwysers te versamel, terwyl semi-gestruktureerde onderhoude gebruik is om data van die hoofde van skole te kry. Deelnemers was opsetlik geselekteer om te verseker dat geskikte data versamel is. Een- en twintig jeugdiges, twaalf onderwysers en sewe hoofde van skole het aan die studie deelgeneem. Deelnemers is uit vier provinsies en sewe skole gekies. Data is kwalitatief ontleed deur kodering, kategorisering en ontwikkeling van temas wat gebruik is as opskrifte vir die bevindings onder elke welstands-dimensie. Die ontwikkelde temas het bewys dat skole moeite gedoen het om die welstand van jeugdige oortreders te bevorder. Daar was groot vordering, veral in die bevordering van die fisiese en spirituele welstand van jeugdige oortreders deur die betrokkenheid van verskillende belanghebbendes. Skole het verskillende uitdagings in die gesig gestaar in hul pogings om die welstand van jeugdige oortreders te handhaaf. Sommige van die uitdagings was ’n tekort aan hulpbronne, geskoolde personeel sowel as onvoldoende betrokkenheid van belanghebbendes. Die navorsing stel ’n holisties welstandsmodel voor om onderwysers en ander belanghebbendes te help wat betrokke raak in die rehabilitasie van jeugdige oortreders en bevordering van hul sosiale, fisiese, emosionele, spirituele,loopbaan en intellektuele welstand. / Psychology / Ph. D. (Psychology)