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Rekenaargesteunde instelling van gekoppelde-resoneerderfilters deur die gebruik van modelgebaseerde parameteronttrekkingVan der Colff, A. P. E. 03 1900 (has links)
Thesis (MEng) -- Stellenbosch University, 2002. / ENGLISH ABSTRACT: The tuning of coupled-resonator filters is an essential part of its production. It is, however, a time
consuming and expensive process. The use of model-based parameter extraction algorithms as a
semi-automated tuning procedure is examined.
This thesis describes the development of such a procedure. Different models for the filter are
compared. The extraction algorithm is based on the least squares method. A more robust
procedure is presented which makes the parameter extraction possible, without the availability of
good starting values.
The algorithm is evaluated using a fourth order single mode direct coupled cavity filter with a
centre frequency of 10GHz. The algorithm produces good results and makes the tuning of this type
of filter possible in an effective way. It also allows for the diagnosis of the filter, which is a great
advantage over the more conventional direct tuning methods. / AFRIKAANSE OPSOMMING: Die instelling van gekoppelde-resoneerderfilters is ’n essensiele deel van die vervaardiging
daarvan. Dit is egter ’n tydsame en duur proses. Die gebruik van modelgebaseerde
parameteronttrekking as ’n semi-geoutomatiseerde instellingsproses is ondersoek.
Hierdie tesis beskryf die ontwikkeling van so ’n prosedure. Verskillende modelle vir die filter is
vergelyk. Die onttrekkingsalgoritme is gebaseer op die kleinste-kwadraatmetode. ’n Meer
robuuste metode word voorgestel wat die parameteronttrekking moontlik maak, sonder dat daar
goeie beginwaardes beskikbaar is.
Die algoritme word geevalueer aan die hand van ’n vierde orde enkelmodus direkgekoppelderesoneerderfilter
met ’n senterfrekwensie van 10GHz. Die algoritme lewer goeie resultate en maak
die instelling van hierdie tipe filter moontlik op ’n effektiewe wyse. Die metode kan ook gebruik
word vir die diagnose van die filter wat ’n groot voordeel is bo meer konvensionele direkte
instellingsmetodes.
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The design of a coupled co-axial resonator filter for low earth orbit satellites working at microwave frequenciesSam, Lwazi 12 1900 (has links)
Thesis (MScEng)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Keywords: Coupled resonator filters, Co-axial line resonators, Basic Coupling
Design, Co-axial resonator filter
The study of the basic dynamics of filters, with the emphasis on coupled resonator
filters, is presented. Special attention is paid to the synthesis of doubly terminated
coupling matrices using the Darlington method. Due to restrictions placed on the
filter by the equivalent circuit used, a coupling matrix reduction is applied to the
resulting coupling matrix.
An investigation is performed on A/2 co-axial line resonators, with the emphasis on
rectangular co-axial line resonators with a round center conductor. The basic
definition of the coupling coefficient is revisited and it is calculated using the method
based on Bethe's theory and Cohn's experimental work.
A 4th-order co-axial resonator filter operating at 3 GHz is designed using the theory
outlined in this thesis. The measured response is in good agreement with the theory in
terms of the center frequency, but disagree in terms of the coupling coefficient,
bandwidth and Q-factor. The reasons for this, as well as suggestions for improving
the accuracy of the parameters mentioned, are given. / AFRIKAANSE OPSOMMING: Sleutelwoorde: Gekoppelde resoneerder filters, Ko-aksiale lyn resoneerders,
Basiese Koppeling Ontwerp, Ko-aksiale resoneerder filter
Die studie van die basies dinamika van filters, met die klem op gekoppelde
resoneerder filters, is voorgelê. Spesiale aandag is gegee aan die sintese van
dubbelbelaste koppel matrikse met die gebruik van die Darlington metode. As gevolg
van die beperkings wat op die filter geplaas word deur die gebruik van die ekwivalent
stroombaan, word 'n koppel matriks vermindering gebruik.
'n Ondersoek is gedoen op A/2 ko-aksiale lyn resoneerders, met die klem op
reghoekige ko-aksiale lyn resoneerders met 'n ronde binnegeleier. Die basiese
definisie van die koppel koëffisiënt is hersien en dit is bereken met die gebruik van
die metode wat baseer is op Bethe se teorie en Cohn se experimentele werk.
'n 4de-orde ko-aksiale resoneerder filter wat opereer by 3 GHz is ontwerp met die
gebruik van die teorie wat in hierdie tesis gaskets word. Die gemete weergawe is in
goeie ooreenkoms met die teorie in terme van die senter frekwensie, maar verskil in
terme van die koppel koëffisiënt, bandwydte en Q-faktor. Die rede hiervoor, as ook
voorstelle vir die verbetering van die akkuraatheid van die parameters wat genoem is,
IS gegee.
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Novel single-band and multi-band bandstop filters for modern wireless communication systemsEsmaeili, Mahbubeh 29 April 2016 (has links)
The objective of this thesis is to introduce novel procedures and guidelines to design
bandstop microwave filters for modern terrestrial and satellite wireless communication
systems. Among all available microwave filter technologies, planar structures
of microstrip and substrate integrated waveguide (SIW) are chosen, due to ease of
fabrication, low profile, weight and manufacturing cost. Particularly, SIW structures
are more attractive because they have a better insertion loss, quality factor, and
power handling capability in comparison to their microstrip counterparts, and can
also be easily integrated into other planar circuitries.
A comprehensive hybrid analytic-optimization method is developed to synthesize
any single-band as well as multi-band bandstop coupling matrix. In this method, the
location of reflection zeros (RZs) and the attenuations in stopbands can be determined
in advance.
Several novel single-band, dual-band, and triple-band bandstop filters are designed
using regular and ridged SIW resonators, in-line coupled singlet resonators,
cross-coupled resonators, and bandstop stubs. The designed filters have fractional
bandwidths up to 23% . Moreover, a tunable ridged SIW bandstop resonator and a
tunable CPW resonator, etched into the top plate of the SIW transmission line, are introduced. Combining these two resonators, a dual-band SIW filter is designed that
permits one of its stopband to be tuned while another stopband is fixed.
All introduced filters in this thesis are verified by commercial electromagnetic
software, analytic investigations using Matlab codes, and measurements. / Graduate
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Electronically adjustable bandpass filterTerblanche, Phillip 12 1900 (has links)
Thesis (MScEng)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: This thesis presents the study, analysis and design of electronically tunable filters, that can be tuned over a wide
frequency range (20-500MHz), for use in a direct sampling receiver. The final design does not have to be a
single filter, but may be comprised of a filter bank which enables switching between the filters. The band of
interest is too low to use normal transmission lines and lumped elements have to be used. Different topologies
that can implement Coupled Resonator filters with lumped elements are investigated. Devices that can be used
for tuning are also investigated and varactor diodes are found to be the most suitable tuning devices currently
available. Two filters, one at the high-end and one at the low-end of the band, were designed and built, both
using varactor diodes. These filters perform well in terms of tuning range, but achieving low losses with current
technologies in this band remains difficult. / AFRIKAANSE OPSOMMING: Hierdie tesis meld die studie, analise en ontwerp van elektronies verstelbare filters, wat verstelbaar is oor ’n
wye band (20-500MHz), vir gebruik in ’n direk-monster-ontvanger. Die finale ontwerp hoef nie ’n enkele filter
te wees nie, maar kan bestaan uit ’n filterbank wat skakeling tussen die filters toelaat. Die betrokke band is
te laag vir die gebruik van normale transmissielyne en diskrete komponente moet gebruik word. Verskillende
topologieë wat gekoppelde resoneerder filters implementeer met diskrete komponente is ondersoek. Verstelbare
komponente word ook ondersoek en varaktor diodes blyk die mees geskikte verstelbare komponent wat huidig
beskikbaar is in hierdie band. Twee filters, een aan die hoë kant en een aan die lae kant van die band, is ontwerp
en gebou, beide met varaktor diodes. Hierdie filters het wye verstelbare bereik, maar dit is steeds moeilik om
verliese te beperk met die huidige tegnologie.
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Composants à ondes élastiques de surface pour le filtrage à gabarits maîtrisés aux fréquences radios pour applications spatiales et professionnelles / Surface acoustic wave filters with mastered charactéristics in the radiofrequency range dedicated to aerospace and professional applicationsBraun, Loïc 06 July 2015 (has links)
Ce mémoire traite de l’ étude et de la réalisation de composants à ondes élastiques de surface (SAW) pour des applications de filtrage dans les gammes VHF et UHF. Nous y étudions différentes structures de ces filtres, à commencer par des filtres à couplage acoustique longitudinal centrés aux alentoursdu gigahertz, de bande passante relative inférieure à 0,1 % réalisés sur quartz. Leur fabrication et leur caractérisation ont révélé des pertes d’insertion inférieures à 5 dB et des niveaux de rejet supérieurs à 20 dB, conformément aux prévisions de notre modèle de matrice mixte. Un tel filtre a été inséré dans un oscillateur pour valider la fonction réalisée. Pour une maîtrise accrue de la conception de ces filtres, nous avons développé un modèle tenant compte de la contribution des modes transverses sur leur fonction de transfert. Des comparaisons entre théorie et expérience ont permis de démontrer la précision de ce modèle. Nous nous sommes également intéressés à des structures de filtres à éléments d’impédance et à transducteurs en éventails (fan-shaped) pour la réalisation de bandes passantes relatives comprises entre 1 et 15 % dans la bande 100 − 300 MHz. Pour chacune de ces structures, nous avons développé un modèle permettant d’en étudier le comportement. Une configuration de filtre en treillis de bande passante relative proche de 2 %a été fabriquée et caractérisée, ainsi que plusieurs filtres à transducteurs en éventails de bandes passantes relatives supérieures à 10 %. Enfin, nous avons étudié deux approches qui nous ont permis de réaliser des dispositifs fonctionnant à des fréquences voisines de 3 GHz. La première, consiste à exploiter les vitesses de phase supérieures à 5 km.s−1 d’un guide d’ondes à base de carbone-diamant. La seconde exploite la résolution d’un procédé de lithographie par nano-impression pour réduire la période des réseaux d’ électrodes. / This thesis deals with the development of surface acoustic wave devices (SAW) for filtering applications in the VHF and UHF bands. Several filter structures are studied. The first ones are longitudinally coupled resonator filters (LCRF) manufactured on Quartz with a relative pass-band narrower than 0,1 % centered at about 1 GHz. These filters have been fabricated and characterized, yielding less than 5 dB insertion loss with rejection levels in excess of 20 dB as predicted by our P-matrix model. One of these filters has been mounted in an oscillator to validate its characteristics.To improve the design of such filters, we have developed a model accounting for transverse mode contributions on their spectral function. Comparisons between theory and experiment emphasizes the accuracy of the developed model. We also have investigated impedance element and slanted transducers (fan-shaped) filter structures to produce filters with relative pass-band ranging from 1 to 15 % in the 100 − 300 MHz frequency range. For each type of filters, we have developed a model to predict their electrical response. A balanced-bridge filter configuration with a 2 % relative pass-band and four fan-shaped filters with pass-band larger than 10 % have been fabricated and characterized. Finally, we have studied two approaches for the development of SAW devices operating at frequencies in the vicinity of 3 GHz. The first approach exploits Diamond-based substrates, providing phase velocity higher than 5 km.s−1. The second one uses a nano-imprint lithography process to reduce the pitch of electrode gratings.
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