The global market of mobile and wireless communications is witnessing explosive growth in size as well as radical changes. Third generation (3G) wireless systems have recently been deployed and some are still in the process. 3G wireless systems promise integration of voice and data communications with higher data rates and a superior quality of service compared to second generation systems. Unfortunately, more and more communication standards continue to be developed which ultimately requires specific RF/MW and baseband communication integrated circuits that are designed for functionality and compatibility with a specific type of network. Although communication devices such as cellular phones integrate different services such as voice, Bluetooth, GPS, and WLAN, each service requires its own dedicated radio transceiver which results in high power consumption and larger PCB area usage. With the rapid advances in silicon CMOS integrated circuit technology combined with extensive research, a global solutionswhich aims at introducing a global communication system that encompasses all communication standards appears to be emerging. State of the art CMOS technology not only has the capability of operation in the GHz range, but it also provides the advantage of low cost and high level of integration. These features propel CMOS technology as the ideal candidate for current trends, which currently aim to integrate more RF/MW circuits on the same chip. Armed with such technology ideas such as software radio look more attainable than they ever were in the past. Unfortunately, realizing true software radio for mobile applications still remains a tremendous challenge since it requires a high sampling rate and a wide-bandwidth Analog-to-Digital converter which is extremely power hungry and not suitable for battery operated mobile devices. Another approach to realize a flexible and reconfigurable RF/MW transceiver that could operate in a diverse mobile environment and provides a multiband and multistandard solution. The work presented in this thesis focuses on the design of an integrated and tunable low-noise amplifier as part of software defined radio (SDR).

A tendência do mercado da microeletrônica é integrar em um mesmo chip sistemas eletrônicos completos, incluindo simultaneamente circuitos analógicos, digitais e RF. Por causa da complexidade do problema de projeto, a parte analógica e RF desses sistemas é o gargalo do desenvolvimento. Uma alternativa de projeto para circuitos analógicos é formular o projeto como um problema de otimização matemática conhecido como programação geométrica. As vantagens são: o ótimo global é obtido eficientemente, e é possível fazer automatização do projeto. A principal desvantagem é que não todos os parâmetros e equações que modelam um circuito são compatíveis com a forma desse problema de otimização. Os receptores para sistemas de comunicação modernos realizam o processo de downconvertion usando uma freqüência intermediária baixa ou diretamente em banda-base. As topologias de receptor Zero-IF e Low-IF são preferidas por sua alta capacidade de integração e baixo consumo de área e de potência. Os filtros analógicos são blocos de composição básicos nesses sistemas. Neste trabalho é desenvolvida uma metodologia de projeto baseada na aplicação de programação geométrica para projeto de filtros Gm-C. A metodologia de projeto foi usada para projetar filtros analógicos complexos e reais para os padrões de comunicação Bluetooth e Zigbee IEEE/802.15.4. Os resultados obtidos mostram que a metodologia de projeto proposta neste trabalho é uma solução efetiva para reduzir o tempo de projeto e otimizar o desempenho de filtros analógicos. / The tendency of the microelectronic market is to integrate in the same chip complete electronic systems, including digital, analog and RF circuits simultaneously. The analog part of those systems represents the bottleneck in the design process. The complexity of analog design makes this one an intuitive and creative process but time expensive. An alternative methodology for analog integrated circuits design is to represent the design as a mathematical optimization problem known as geometric programming. The advantages are: global optimum achieved efficiently, and the possibility of design automation. The main disadvantage, is that all the parameters or equations that characterize a circuit are not compatible with the form of this optimization problem. Modern receivers perform downconvertion of the signal using very low, or zero intermediate frequency. Zero-IF and Low-IF topologies are preferred because of their high integration capabilities, and low area and power consumption. Analog filters are basic building blocks of such systems. In this work, a design methodology based on geometric programming is developed, for automated and optimal design of Gm-C filters. The design methodology was used to design analog complex and real filters for the digital communications standards Bluetooth and Zigbee IEEE/802.15.4. The results show that the design methodology proposed in this work is an effective solution for fast, automated and optimal analog filter design

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The University of Canberra (UC) has been involved in GPS processing since the late 1980s. This processing commenced with the GOTEX 1988 campaign and progressed through a series of project specific regional campaigns to the current daily processing of a distributed set of continuously operating sites for the determination of precise GPS station positions for user applications. Most of these earlier campaigns covered only short periods of time, ranging from a few weeks to multiple occupations of a few days to a time over one to two years. With software developments, these multiple occupations were able to be combined to produce results from which crustal motion velocities could be extracted. This first became feasible with the processing of the Australian National Network (ANN), which yielded realistic tectonic velocities from two occupations (1992 and 1993) of sites 12 months apart. Subsequently, this was successfully extended by a further 12 months, with re-occupation of certain sites for a third time in 1994. Analysis of the results indicated that the accuracy of determining the earth signals improved as the time span from first to last observation was increased. The same was true also for the determination of the position of global references sites. However, by current standards the results achieved were poor. Consequently, the process was extended to combine the results of subsequent campaigns with the original ANN data set. From 1995 to 1999, campaigns were conducted across Australia, covering many State and tide gauge sites included in the original ANN solution. These provided additional multiple occupations to improve the determinations for both position and velocity. UC has maintained a data set of the global IGS sites, commencing with the IGS pilot campaign of 1992. Daily data sets for those global sites, which contained days common to the regional campaigns, were processed to produce our own independent global orbit and reference frame connection. The motivation for doing so was fourfold. �Firstly, to see if historic data could be reprocessed using current modern software and thus be able to be incorporated in this and other analysts research programs. �Secondly, to compare the results of the reprocessing of the original data set using modern software with the original ANN solution and then validate both the solutions. �Thirdly, to extend the timespan of observations processed to include more recent campaigns on as many original sites as possible. This to achieve a stronger solution upon which to base the determination of an Australian tectonic plate velocity model and provide quality assurance on the solution comparisons with re-observed sites. �Fourthly, to develop a set of transformation parameters between current coordinate systems and the GDA94 system so as to be able to incorporate new results into the previous system. The final selection of regional and global sessions, spanning from mid 1992 to late 2002, contained almost 1000 individual daily solutions. From this 10 year data span a well determined rigid plate tectonic motion model was produced for Australia. This site velocity model was needed to develop a transformation between the thesis solution in ITRF00 an the GDA94 solution in ITRF92. The significant advantage of the plate velocity model is that all Australian sites can now have computed a realistic velocity, rather than being given a value which has been interpolated between sites whose velocities had been determined over a one or two year span. This plate velocity model is compared with the current tectonic motion NNR-NUVEL-1A model and other recently published models. To perform the comparison between the thesis solution in ITRF00 and the GDA solution in ITRF92 a transformation was developed between the two reference systems. This set of transformation parameters, in conjunction with the plate velocity model developed, enables site solutions at any epoch in the current ITRF00 to be converted onto the GDA94, and vice versa, with a simple, non-varying seven parameter transformation. The comparisons between the solutions are analysed for both horizontal position and height consistency. There were 77 sites whose differences were compared. The horizontal consistency was within estimated precisions for 75 of the 77 sites. However, the vertical comparisons revealed many of the single epoch sites, especially in 1992, have inconsistent results between the two solutions. The heights from this thesis for some West Australian sites were compared with analysis done by DOLA and the height recoveries are very similar, indicating a weakness in the GDA94 solution for some of the single epoch sites. Some of these differences have been resolved but others are still under investigation. This thesis describes the repocessing of the original ANN data set, the addition of later data sets, the results obtained, and the validation comparisons of the old and new solutions. As well as the plate velocity model, transformation is provided which enables the user to compute between the GDA94 system, and any epoch result in ITRF00. Recommendations are made as to which sites need additional work. This includes sites which only need further analysis or investigation and those which require further observations to achieve a result which will have acceptable accuracy and reliability.

Electronic Support Measures is a discipline of electronic warfare. In electronic support measures, receivers must maintain surveillance over the very wide portion of the electromagnetic spectrum in which threat emitters operate. In current receiver technology, it is not possible to have a receiver which is at once both able to discriminate multiple simultaneous emissions and highly sensitive. A common approach is to use a receiver with a relatively narrow bandwidth that sweeps its centre frequency over the threat bandwidth to search for emitters. The sequence and timing of changes in the centre frequency constitute a search strategy or sensor scheduling problem. A good electronic support receiver should observe the threat emitters, usually radars, very soon after it first begins transmitting, so in designing search strategy we would like to ensure that the intercept time is low or the probability of intercept after a specified time is high. In this thesis, we study the search strategies used in electronic support measures receivers. Moreover, a search strategy based on probability of intercept of the threats is proposed. The performances of the search strategies are compared at the end of the thesis.

The objective of the research presented in this dissertation is to explore the achievable dynamic range limits in high-performance RF front-ends designed using SiGe HBTs, with a focus on complementary (npn + pnp) SiGe technologies. The performance requirements of RF front-ends are high gain, high linearity, low dc power consumption, very low noise figure, and compactness. The research presented in this dissertation shows that all of these requirements can easily be met by using complementary SiGe HBTs. Thus, a strong case is made in favor of using SiGe technologies for designing high dynamic range RF front-ends. The contributions from this research are summarized as follows: 1. The first-ever comparison study and comprehensive analysis of small-signal linearity (IIP3) for npn and pnp SiGe HBTs on SOI. 2. A novel comparison of large-signal robustness of npn and pnp SiGe HBTs for use in high-performance RF front-ends. 3. A systematic and rigorous comparison of SiGe HBT compact models for high-fidelity distortion modeling. 4. The first-ever feasibility study of using weakly-saturated SiGe HBTs for use in severely power constrained RF front-ends. 5. A novel X-band Low Noise Amplifier (LNA) using weakly-saturated SiGe HBTs. 6. Design and comprehensive analysis of RF switches with enhanced large-signal linearity. 7. Development of novel methods to reduce crosstalk noise in mixed-signal circuits and the first-ever analysis of crosstalk noise across temperature. 8. Design of a very high-linearity cellular band quadrature modulator for use in base-station applications using first-generation complementary SiGe HBTs.

La tesi estudia el problema de la síntesi de freqüències en les bandes de freqüències de microones i ones mil·limètriques, i la seva aplicació al disseny dels oscil·ladors locals d'un receptor coherent per a la recepció de les *radiobalises que a 12, 20 i 30 GHz emetia el satèl·lit Olympus de l'Agència Espacial Europea (ESA), amb la finalitat de caracteritzar el comportament radioelèctric de l'atmosfera a aquestes freqüències, a partir de mesures d'atenuació i transpolarització sobre aquests senyals de test, tot això dintre del marc d'un experiment de propagació (OPEX) propiciat per l'agència.La tesi s'ha centrat en l'estudi dels sistemes de síntesis de freqüències utilitzats habitualment, i especialment en els de síntesi indirecta de freqüència basats en sistemes Phase Locked Loop (PLL) a freqüències de microones ja que són la base sobre la qual s'han dissenyat i construït els prototips de multiplicadors de freqüència que s'han desenvolupat, capaços de sintetitzar senyals en bandes de mil·limètriques, que en el nostre cas s'han restringit al marge de 1 a 29 GHz.Alguns dels multiplicadors fan ús de la detecció de fase harmònica, sistema que permet realitzar multiplicacions de freqüència d'índex imparell, evitant la utilització de divisors de freqüència en el llaç de realimentació del PLL.La tesi s'estructura en quatre parts diferenciades. La primera, amb un caire eminentment teòric, s'ofereix a manera de revisió dels aspectes del soroll de fase i dels sistemes de síntesis de freqüències existents. La segona part aborda les qüestions derivades de la síntesi de freqüències en microones mitjançant PLL's, amb descripció dels components utilitzats, per a passar a tractar dels aspectes de disseny d'un receptor coherent, els seus requisits i aplicacions. En la tercera part es presenten els multiplicadors de freqüència realitzats, la seva descripció, esquema de blocs i resultats experimentals obtinguts. I finalment, en la quarta part s'inclouen una sèrie de realitzacions derivades de la utilització de sistemes PLL a freqüències de microones, amb sincronització per injecció del VCO al senyal de referència, en aplicacions de combinació de potència i de control electrònic de fase en sistemes phased-arrays amb elements actius. / La tesis estudia el problema de la síntesis de frecuencias en las bandas de frecuencias de microondas y ondas milimétricas, y su aplicación al diseño de los osciladores locales de un receptor coherente para la recepción de las radiobalizas que a 12, 20 y 30 GHz emitía el satélite Olympus de la Agencia Espacial Europea (ESA), con la finalidad de caracterizar el comportamiento radioeléctrico de la atmósfera a estas frecuencias, a partir de medidas de atenuación y transpolarización sobre esas señales de test, todo ello dentro del marco de un experimento de propagación (OPEX) propiciado por la agencia.La tesis se ha centrado en el estudio de los sistemas de síntesis de frecuencias utilizados habitualmente, y en especial en los de síntesis indirecta de frecuencia basados en sistemas Phase Locked Loop (PLL) a frecuencias de microondas puesto que son la base sobre la que se sustentan los prototipos de multiplicadores de frecuencia que se han desarrollado, capaces de sintetizar señales en bandas milimétricas, que en nuestro caso se han restringido al margen de 1 a 29 GHz.Algunos de los multiplicadores hacen uso de la detección de fase armónica, sistema que permite realizar multiplicaciones de frecuencia de índice impar, evitando el empleo de divisores de frecuencia en el lazo de realimentación del PLL.La tesis se estructura en cuatro partes diferenciadas. La primera, con un cariz eminentemente teórico, se ofrece a modo de revisión del tema del ruido de fase y de los sistemas de síntesis de frecuencias existentes. La segunda parte aborda las cuestiones derivadas de la síntesis de frecuencias en microondas mediante PLL's, con descripción de los componentes utilizados, para pasar a tratar de los aspectos de diseño de un receptor coherente, sus requisitos y aplicaciones. En la tercera parte se presentan los multiplicadores de frecuencia realizados, su descripción, esquema de bloques y resultados experimentales obtenidos. Y por último, en la cuarta parte se incluyen una serie de realizaciones derivadas de la utilización de sistemas PLL a frecuencias de microondas, con sincronización por inyección del VCO a la señal de referencia, en aplicaciones de combinación de potencia y de control electrónico de fase en sistemas phased-arrays con elementos activos. / The thesis studies the problem of the synthesis of frequencies in the microwave and millimeter waves frequency bands, and its application to the design of the local oscillators of a coherent receiver for the reception of the radio beacons that to 12, 20 and 30 GHz emitted the satellite Olympus from the European Space Agency (ESA), with the aim of characterizing the radio behavior of the atmosphere at these frequencies, from measurements of attenuation and transpolarisation on those signals of test, all that in the framework of a propagation experiment (OPEX) favored by the agency.The thesis has been focused on the study of the frequency synthesis systems, and especially on the indirect frequency synthesis systems based on Phase Locked Loops (PLL) at microwave frequencies, since they are the base on which the prototypes of frequency multipliers that they have been developed, capable of synthesizing signals in millimeter bands, are held that in our case they have restricted regardless of 1 to 29 GHz.Some of the multipliers make use of the harmonic phase detection system that allows carrying out frequency multiplications of odd index, preventing the use of frequency dividers in the feedback loop of the PLL.The thesis is structured in four differentiated parts. The first, with an eminently theoretical look, offers like revision of the subject of the phase noise and the methods of frequency synthesis. The second part tackles the questions derived from the synthesis of frequencies in microwaves through PLL's, with description of the used components, to pass to deal of the aspects of design of a coherent receiver, its requirements and applications. In the third part the frequency multipliers carried out, its description, schema of blocks and obtained experimental results are presented. And finally, in the fourth part a series of accomplishments are included phased-arrays derived of the use of systems PLL at frequencies of microwaves, with synchronization by injection of the VCO to the reference signal, in applications of power combination and of electronic phase control in systems with active elements.

Monte Carlo algorithms can be used to estimate the state of a system given relative observations. In this dissertation, these algorithms are applied to physical layer communications system models to estimate channel state information, to obtain soft information about transmitted symbols or multiple access interference, or to obtain estimates of all of these by joint estimation. Initially, we develop and analyze a multiple access technique utilizing mutually orthogonal complementary sets (MOCS) of sequences. These codes deliberately introduce inter-chip interference, which is naturally eliminated during processing at the receiver. However, channel impairments can destroy their orthogonality properties and additional processing becomes necessary. We utilize Monte Carlo algorithms to perform joint channel and symbol estimation for systems utilizing MOCS sequences as spreading codes. We apply Rao-Blackwellization to reduce the required number of particles. However, dense signaling constellations, multiuser environments, and the interchannel interference introduced by the spreading codes all increase the dimensionality of the symbol state space significantly. A full maximum likelihood solution is computationally expensive and generally not practical. However, obtaining the optimum solution is critical, and looking at only a part of the symbol space is generally not a good solution. We have sought algorithms that would guarantee that the correct transmitted symbol is considered, while only sampling a portion of the full symbol space. The performance of the proposed method is comparable to the Maximum Likelihood (ML) algorithm. While the computational complexity of ML increases exponentially with the dimensionality of the problem, the complexity of our approach increases only quadratically. Markovian structures such as the one imposed by MOCS spreading sequences can be seen in other physical layer structures as well. We have applied this partitioning approach with some modification to blind equalization of frequency selective fading channel and to multiple-input multiple output receivers that track channel changes. Additionally, we develop a method that obtains a metric for quantifying the convergence rate of Monte Carlo algorithms. Our approach yields an eigenvalue based method that is useful in identifying sources of slow convergence and estimation inaccuracy.

Radar systems have been very effective in gathering information in a battlefield, so that the tactical actions can be decided. On the contrary, self-protection systems have been developed to break this activity of radars, for which radar signals must be intercepted to be able to take counter measures on time. Ideally, interception should be done in a certain time with a 100% probability, but in reality this is not the case. To intercept radar signals in shortest time with the highest probability, a search strategy should be developed for the receiver. This thesis studies the conditions under which the intercept time increases and the probability of intercept decreases. Moreover, it investigates the performance of the search strategy of Clarkson with respect to these conditions, which assumes that a priori knowledge about the radars that will be intercepted is available. Then, the study identifies the cases where the search strategy of Clarkson may be not desirable according to tactical necessities, and proposes a probabilistic search strategy, in which it is possible to intercept radar signals with a specified probability in a certain time.

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy