Design and optimization of gap waveguides components through space mapping

Date
2018-03
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: This thesis presents a detailed approach and method to design and optimise ridge and groove gap waveguide components using input space mapping. Gap waveguides are expected to contribute significantly towards the implementation of microwave components especially for the millimetre and sub-millimetre wavelengths. This is due to their manufacturing flexibility, low loss and good power handling capabilities when compared to conventional rectangular waveguides and transmission lines. The application of the space mapping technique to speed up the design and optimisation of gap waveguide components, which traditionally rely heavily on slower full wave simulations of the structures, is demonstrated through the use of simple circuit models. The application of a stripline model to design and optimise ridge gap waveguide components through space mapping is presented. Input space mapping, which is the most basic and original version of space mapping, is successfully applied in the optimisation of a 3-dB ridge gap waveguide power divider and hybrid coupler using a computationally cheap but faster stripline model. A transmission line model is also used in the design and optimisation of third and fifth order narrow band ridge and groove gap waveguide coupled resonator Chebychev bandpass filters using an in-house input space mapping code. The bandpass filters are successfully designed and optimised in a relatively short time through the use of input space mapping with convergent results after only a few computational electromagnetic (CEM) simulations. The results show that using the calculated design parameter values in filters, and generally in gap waveguide component designs, in most cases does not give an optimum design. The design parameters need to be tuned or optimised to meet the design specifications. The transmission line model is shown to give accurate results for the narrow band Chebychev bandpass filters. The filter examples are directly optimised using a built-in computer simulation technology (CST) optimiser and the results are compared with those of input space mapping. The input space mapping technique is shown to give convergent results which meet the design specifications and is significantly faster than the conventional full-wave optimisation approach.
AFRIKAANSE OPSOMMING: Hierdie tesis bied 'n gedetailleerde benadering en metode aan vir die ontwerp en optimering van rif en gleuf gaping-golfleier komponente deur intree ruimtekartering. Daar word verwag dat gaping-golfleiers 'n beduidende bydra sal maak in die implementering van mikrogolf komponente - veral in die millimeter en sub-millimeter golflengte bande. Dit is te danke aan die vervaardigings tegniek buigbaarheid, lae verliese en goeie drywing hanterings vermoë in vergelyking met konvensionele reghoekige golfleiers en transmissielyne. Die toepassing van die ruimtekarteringstegniek op die versnelde ontwerp en optimering van gaping-golfleier komponente, wat tradisioneel swaar steun op volgolf numeriese elektromagnetiese simulasies in hulle ontwerp, word deur die gebruik van eenvoudige stroombaan modelle geïllustreer. Die toepassing van 'n strooklyn model om rif gaping golfleier komponente te ontwerp en optimeer word voorgehou. Intree ruimte kartering, wat die eenvoudigste en oorspronklike weergawe van ruimtekartering is, word suksesvol toegepas in die optimering van 'n 3-dB rif gaping-golfleier drywingsverdeler en hibriede koppelaar deur van 'n numeries goedkoop en vinniger strooklyn model gebruik te maak. 'n Transmissielyn model word ook gebruik in die ontwerp en optimering van derde en vyfde orde nouband rif en gleuf gaping-golfleier gekoppelde resoneerder Chebyshev banddeurlaatfilters deur van 'n in-huis ruimtekartering kode gebruik te maak. Die banddeurlaatfilters word in 'n relatiewe kort tydperk ontwerp en geoptimeer deur van intree ruimtekartering gebruik te maak, en gekonvergeerde resultate word na slegs 'n paar numeriese elektromagnetiese simulasie lopies verkry. Die resultate toon dat om die oorspronklike ontwerpsparameters te gebruik in filters, en in die algemeen in gaping-golfleier komponente, in meeste gevalle nie die optimum resultate tot gevolg het nie. Die ontwerpsparameters moet ingestem en geoptimeer word om die ontwerpspesifikasies te haal. Daar word getoon dat die transmissielyn modelle redelike akkurate resultate vir die nouband Chebychev filters lewer. Die filter voorbeelde word ook direk geoptimeer deur van die ingeboude optimeerder in CST gebruik te maak, en die resultate word vergelyk met die van die intree ruimtekartering. Daar word sodoende getoon dat die intree ruimtekarterings tegniek konvergente resultate lewer, wat die ontwerp spesifikasie haal, en dat dit beduidend vinniger is as die konvensionele volgolf optimerings tegniek.
Description
Thesis (MEng)--Stellenbosch University, 2018.
Keywords
Wave guides -- Design and construction, UCTD, Wave guides, Mappings (Mathematics), Electromagnetic measurements
Citation