Thesis (Ph. D.)--University of Adelaide, Dept. of Electrical and Electronic Engineering, 1992. / Includes bibliographical references (leaves 222-230).

Zugl.: Erlangen, Nürnberg, University, Diss., 2009.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002. / Includes bibliographical references. Also available in electronic version. Access restricted to campus users.

Reconfigurable filters are an attractive solution for many military and commercial applications due to their ability to alter the partitioned frequency band in an RF system without requiring a bank of fixed filters. The onset of this technology has the potential to revolutionize the RF industry by allowing for agile devices which consume less size, weight, and power while providing greater performance. However, at the present state, reconfigurable filters present a reduction in performance when compared to filter banks. This has led to exciting research in the field of RF tunable filters. For many applications, planar reconfigurable filters have been utilized due to their low cost of manufacturing and ease of implementation in a system. One topology that has proven to be versatile in design is the combline filter which employs line resonators loaded with a capacitor to obtain a predetermined response. To implement a varying center frequency reconfigurable combline filter, the resonator is loaded with a capacitance that can be tuned either digitally or continuously by presenting a DC voltage. Due to their ease of use and availability, varactors are a common choice as they provide a continuously tunable capacitance by presenting a reverse bias voltage to the device. To continue the trend of lowering size, weight and power while maintaining high vitality in performance, consolidation of RF components may prove to be a good next step. Tunable balun filters have already been presented as a viable option for consolidation of components and show good performance. However, those designs which have been presented do not demonstrate a topology that can implement higher than a second order filter. This project, for the first time, investigates the consolidation of the Marchand balun and the combline filter into a single topology which allows for quick adaption of higher order filters while maintaining vigor in performance. A design is presented which achieves 25% tuning bandwidth centered at 1.5 GHz with less than 5 dB insertion loss, a phase balance of 180 ± 1° and an amplitude difference of ± 0.6 dB.

This paper investigates the viability of two different mappings of two parameters of the digital musical instrument Force Ghost. The instrument produces sound by having an  ambience (a recording of rain or of waves on the beach) filtered by bandpass filters  whose center-frequencies are controlled by a midi-keyboard. Five bandpass filters are assigned to each note, corresponding to the fundamental frequency its and its multiples (2f,3f,4f,5f). The mapped parameters are the Q-factor of the bandpass filters and the timbre, defined as the relative level between the even and odd multiples harmonics. These two parameters are mapped to the modulation wheel and the pitch bend wheel. The mappings of the parameters are investigated with the help of musical tasks completed by musicians rounded up with semi-structured interviews. The interviews revealed that the modulation wheel was to be prefered due to the lack of a spring mechanism (which is an attribute of the pitch bend wheel), forcing the wheel back to its default position (in the middle) when released. The results from the musical tasks suggested an indication that none of the sensors have better controllability than the other, regardless of parameter it controls. In conclusion, a sensor that gravitates towards a resting state does not seem to be suitable to control a parameter (scaling) that lacks a “resting value” (as perceived by musicians). / Denna artikel utreder två mappningar av två parametrar hos det digitala musikaliska instrumentet Force Ghost. Instrumentet ljuder genom att en ljudkälla filtreras av bandpassfilter. Ljudkällan i detta fall är ljudet av regnfall i en skog. Varje tangent på ett keyboard är kopplat till minst ett bandpassfilter, vars MIDI-not kopplat till motsvarande frekvens. Denna frekvens är bandpassfiltrets centerfrekvens. När en tangent nedtrycks genereras bandpassfiltret, vilket skapar en ton ur ljudkällan. De två parametrarna i fokus är kopplade till bandpassfiltrerna. De är Q-värdet (kopplat till bandpassfiltrernas bandbredd) och klangfärgen (kopplat till övertonerna; vilka de är och deras amplitudrelation för varje not). Dessa två parametrar är mappade till modulations-hjulet och pitchbend-hjulet. Mappningen av dessa parametrar är undersökt genom musikuppgifter och självständig utforskning genomförda av musiker. Detta spelades in och sedan utfördes en semistrukturerad intervju med musikerna. Intervjuerna visade att modulations-hjulet föredrogs på grund av avsaknaden av fjädermekanismen som finns hos pitchbend-hjulet. Denna mekanism tvingar pitchbend-hjulet tillbaka till sin utgångsposition (i mitten) när den släpps. Resultaten från musikuppgifterna indikerar att ingen av sensorerna har bättre kontrollbarhet än den andre, oavsett vilket parameter den kontrollerar. Sammanfattningsvis, en sensor som graviterar mot ett viloläge verkar inte vara lämplig för att kontrollera en parameter (-skalning) som saknar ett “vilovärde” (så som uppfattat av musiker).

A new method of realizing linear, time-invariant digital filters is developed and demonstrated. The result is based on the convolution integral. It is assumed that the specifications of the filter are known and from these, an appropriate analog filter is chosen. The properties of this filter are then retained by digital filter after transformation. The behaviour of lowpass, highpass bandpass and bandstop digital filters is investigated in both the frequency and time domains, for both cascade and parallel structure is superior for lowpass and bandpass digital filters, and that the cascade structure is superior for high pass and bandstop digital filters. / Thesis / Master of Engineering (ME)

No description available.

No description available.

The objective of this PhD research was to design and implement novel microfluidic radio-frequency (RF) structures on multilayer organic substrates for cooling and tuning purposes. The different designs were implemented to target applications up to C-band (4 GHz – 8 GHz) frequencies. The system-on-package (SoP) solution adopted throughout this work is well adapted for such designs where there is a need to integrate the functionality of different sub-components into a single hybrid fully packaged system. The first part of the thesis is dedicated to the study of a specific liquid cooling scheme using integrated microchannels on organics placed beneath different types of heat sources. A 1 W gallium nitride (GaN) die was cooled using this method and an analysis is presented regarding the cases where the coolant is static or dynamic inside the microchannel. The second part of the thesis deals with microfluidically reconfigurable microstrip RF circuits, mainly bandpass filters and power amplifiers (PAs). The microfluidic tuning technique is based on the change in the effective dielectric constant that the RF signal “sees” when traveling above two microchannels with different fluids. This technique was used to shift the frequency response of an L-band microstrip bandpass filter by replacing DI water with acetone inside a 60 mil micro-machined cavity. This technique was also used to design reconfigurable matching networks which constitute the main part of the proposed tunable GaN-based PA for S- and C-band applications. The final part of the thesis expands the previous results by combining both cooling and tuning in a single RF design. To prove the concept, cooling and tuning microchannels were integrated into a single package to cool a GaN-based PA and tune its frequency response at the same time from 2.4 GHz to 5.8 GHz and vice versa.

Esta dissertação de mestrado apresenta uma metodologia de projeto de filtros de microondas planares passa-faixa tipo patch dual-mode, que associam baixas perdas nos condutores, boa capacidade de potência, rejeição da banda de segunda harmônica e miniaturização. Utilizou-se a ferramenta computacional MATLAB para desenvolver programas de cálculo de dimensões de ressoadores patch single-mode em função da freqüência fundamental e do substrato escolhido, bem como para cálculo da distribuição de campos eletromagnéticos (EM) ao longo destes ressoadores. O simulador EM 3D Momentum/ADS foi utilizado na análise, otimização e simulação do desempenho dos filtros. A metodologia desenvolvida consiste no projeto do ressoador patch single-mode nas geometrias quadrada, triangular e circular, com perturbações tais que resultem na freqüência central e banda de passagem desejadas para o filtro, bem como na miniaturização do mesmo. A metodologia engloba a análise do posicionamento das linhas de entrada e de saída para excitação dos modos desejados e seu acoplamento ao ressoador projetado. Foram propostos três ressoadores patch com topologias originais, modificados pela inserção de fendas, os quais foram aplicados ao projeto, construção e caracterização de cinco filtros. Desses, dois filtros passa-faixa dual-mode de banda mediana utilizam a nova topologia proposta de ressoador patch quadrado. Esses filtros, com dois e com quatro pólos, operam em 2,4 GHz e 2,35 GHz, com banda de passagem fracional de 14% e 9,8%, respectivamente. Outros dois filtros passa-faixa dual-mode de banda estreita, um com dois pólos e outro com quatro pólos, utilizam a topologia original proposta de ressoador patch triangular, com fenda em forma de \"T\" invertido. O filtro com dois pólos opera em 7,8 GHz, com banda de passagem fracional de 4,3% e o filtro de quatro pólos, em 7,5 GHz, com banda de 3,5%. Por fim, o filtro passa-faixa circular banda larga utiliza o ressoador patch circular proposto, que foi modificado para operar como triple-mode, comportamento inédito na literatura internacional enfocando ressoadores patch. Esse filtro triple-mode com três pólos apresenta freqüência central de 2,4 GHz e banda fracional de 29%. Os resultados experimentais validam a aplicação da metodologia, que apresenta grande flexibilidade no projeto de filtros com bandas estreitas, medianas ou largas, com boa rejeição na faixa de segunda harmônica (resultados acima de 13 dB). Conseguem-se leiautes miniaturizados com redução em área maior que 50% e ao mesmo tempo sem dimensões críticas, o que resulta em facilidade de fabricação através de métodos tradicionais de fotogravação em placas de circuito impresso. / This dissertation presents a methodology for the design of microwave planar bandpass filters using dual-mode patch resonators, which have low conductor loss, high power handling, second harmonic band rejection and miniaturization. MatLab software was used to develop routines that can calculate the dimensions of the single-mode patch resonators as a function of their fundamental frequency and of the chosen substrate. Further, these routines are able to calculate the electromagnetic (EM) field patterns across these resonators. Momentum/ADS EM 3D software was used for the analysis, optimization and simulation of the performance of the filters. The developed methodology consists on the design of the single-mode patch resonator in either square, rounded or triangular shape with perturbations that result in the desired filter\'s central frequency and bandwidth, and also in its miniaturization. The methodology involves the positioning of the input and output transmission lines to excite the desired modes and their coupling to the developed resonator. Three patch resonators were proposed with novel topologies that were modified by the insertion of slots, and applied to the design, fabrication, and measurements of five filters. Out of these five filters, two are dualmode medium band filters that use the proposed new topology for the square patch resonator. These filters, with two and four poles, are centered at 2.4 GHz and 2.35 GHz, with fractional bandwidth of 14% and 9.8%, respectively. Other two filters are dual-mode narrowband filters, a two-pole and a four-pole, that use the original topology proposed for the triangular patch resonator with a \"T\"-shaped slot. The two-pole filter is centered at 7.8 GHz with fractional bandwidth of 4.3%, whereas the four-pole filter is centered at 7.5 GHz with 3.5% of bandwidth. The last filter is a broadband circular filter that uses the proposed circular triplemode patch resonator, which is a brand new behavior in the international literature that focus on patch resonators. This triple-mode filter with three poles is centered at 2.4 GHz with fractional bandwidth of 29%. Experimental results validate the methodology, which presents wide filter design flexibility with narrow, medium or broad bands, and good second harmonic rejection (results better than 13 dB). Layouts can be designed with more than 50% of area reduction, and without critical dimensions at the same time, resulting in a simple fabrication that utilizes conventional PCB photopatterning process.