In high-speed digital circuits, in order to utilize the space of printed circuit boards efficiently, the signal via is a heavily used interconnection structure to communicate different signal layers. However, the interconnection discontinuities will result in the degradation of the signal integrity and become a crucial issue for IC designers. To analyze the problems accurately and fast using the hybrid physical equivalent model which combining the transmission line model, slot model, via model, and decoupling capacitor model, etc. Based on the method, we can get a good result of simulation and compute faster than Ansoft HFSS. In addition, by the hybrid physical model method, we simulate and discuss several interesting issues such as resonance in power/ground planes, and the effect of the simultaneous switching noise, we also improve the bad effect of the printed circuit boards existing vias by some ways.

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In pneumatic pressure control applications the influence of tubes that connect the valve with the control volume ist mainly neglected. This can lead to stability and robustness issues and limit either control performance or tube length. Modeling and considering tube behavior in controller design procedure allows longer tubes while maintaining the required performance and robustness properties without need for manual tuning. The author\'s previously published Simplified Fluid Transmission Line Model and the proposed model-based controller design enable the specification of a desired pressure trajectory in the control volume while the pressure sensor is mounted directly at the valve. Thus wiring effort is reduced as well as cost and the chance of cable break or sensor disturbance. In order to validate the simulated results the proposed control scheme is implemented on a real-time system and compared to a state-of-the-art pressure regulating valve

In the past two decades carbon nanotubes and graphene have attracted a lot of research attention due to their exceptional electronic properties. The research focus on improving the synthesising techniques will eventually lead to their applications in terahertz wave, millimetre wave and microwave frequencies. In this thesis, a modelling technique based on the transmission line theory is proposed to calculate the 2-port S-parameters of vertically aligned CNT arrays with finite sizes and arbitrary cross sections. The process takes into account all the coupling in the array and gives the analytical solution of S-parameters. The simulation results from the proposed technique are compared with results obtained by effective single conductor model and shows a good matching for small arrays and an increasing difference with the increase of array sizes. From the S-parameters, the fundamental properties of CNT arrays such as input impedance and absorption are obtained and compared with measurement results in microwave frequencies. The dependence of these properties on ambient temperature and host medium are also presented to explore the tunability of CNT arrays. From the Fabry-Perot the wave propagating velocity is also calculated for arrays with different sizes and fitted with a power function. The S-parameters allows the extraction of the complex permittivity, permeability and conductivity of the CNT array. The extracted permittivity and absorption are compared with measurement results. The graphene nanoribbons are simulated in the same manner. The graphene sheet on top of a microstrip gap is simulated using transmission line model at microwave frequencies to show the impact of parasitics and contact resistances. Finally, a graphene based microwave absorber is proposed and modelled under both electric and magnetic bias. The absorber shows good broadband absorption rate and a potential for turning transparent and opaque to microwaves under both electric and magnetic bias.

Thin-film solar cells are widely recognised to have the potential to compete with fossil fuels in the electricity market due to their low cost per peak Watt. The Thin-Film Group at the University of New South Wales (UNSW) is engaged in developing polycrystalline silicon (poly-Si) thin-film solar cells on glass using e-beam evaporation technology. We believe our solar cells have the potential of significantly lowering the manufacturing cost compared to conventional, PECVD-fabricated thin-film solar cells. After years of materials research, the focus of the Group??s work is now moving to the metallisation of evaporated solar cells. Minimising various kinds of losses is the main challenge of the cell metallisation procedure, within which the contact resistance is always a big issue. In this thesis, the contact resistance of aluminium contacts on poly-Si thin-film solar cells on glass is investigated. To the best of the author??s knowledge, this is the first ever contact resistance investigation of Al contacts on evaporated poly-Si material for photovoltaic applications. Various transmission line models (TLM) are employed to measure the contact resistance. An improved TLM model is developed to increase the measurement precision and, simultaneously, to simplify the TLM pattern fabrication process. In order to accommodate the particular requirements of poly-Si coated glass substrates, a TLM pattern fabrication process using photolithography is established. Furthermore, a Kelvin sense tester is set up to ensure an accurate measurement of the contact resistance. After establishment of the TLM technique at UNSW, it is successfully tested on singlecrystalline silicon wafer samples. The thermal annealing process of the contacts is also optimised. Then, the general behaviour of Al contacts on uniformly doped poly-Si films (i.e., no p-n junction) is investigated using the verified TLM technique. The long-term stability of the contacts is also studied. This is followed by an investigation of the contact resistance of the back surface field and emitter layers of different types of poly-Si thin-film solar cells. Finally, a novel contact resistance measurement model is proposed that is believed to be able to overcome the measurement bottleneck of the transmission line models.

In recent high-speed digital circuits with pico-second rising/falling edges, it is reasonable to consider the power/ground planes as a dynamic electromagnetic system. The simultaneous switching noise (SSN) or ground bounce noise (GBN), resulting from the transient currents which flow between power/ground planes during the state transitions of the logic gates, has become a critical factor to degrade the signal integrity (SI) and power integrity (PI) in PCB or package design. In order to accurately perform overall system-level power integrity simulation, extracting the SPICE-compatible models with the resonant effect being considered in the power/ground planes and incorporating the model into the conventional circuit simulator, such as SPICE, is essential. In this thesis, a two-dimensional transmission line (2D-TL) model is proposed for constructing the SPICE-compatible model of the power/ground planes. Based on this model, the ground bounce noise for the BGA package mounted on a PCB can be efficiently evaluated. It is found that the behavior of GBN between the only package and package mounted on a PCB (hybrid structure) is obvious different. Then, we combine the SPICE-compatible model of the power/ground planes with decoupling capacitors to fast evaluate the behavior of GBN. It also has a good agreement between our model and the measured result. Adding decoupling capacitors between the power and ground planes is a typical way to suppress the GBN. However, they are not effective at the frequency higher than GHz due to their inherent lead inductance. In recent, a new method for eliminating the GBN at higher frequency is proposed by electromagnetic bandgap (EBG) structure with high impedance surface (HIS). Finally, we utilize 2D-TL model to fast analyze the behavior of the EBG, and combine decoupling capacitors with EBG structure to research the suppression of the GBN.

For example for battery diagnosis it is essential to understand mechanisms during discharge and because of aging to optimize cell design and operating conditions. Therefore the overall battery behavior can be modeled by combining models of relevant mechanisms like porosity, charge transfer reaction and diffusion. The aim of this contribution is to define one transmission line model for modeling several of these mechanisms. Thereby a sophisticated normalization strategy allows to eliminate ambiguity and to quantify the influence of each model parameter. The results allow a better understanding of impedance measurements and can for example be used for battery diagnosis and simplified simulations of electrochemical systems. Fitting derived impedance models to measurement data by nonlinear parameter extraction techniques allows to monitor battery parameters during discharge and because of aging. Thereby a sophisticated normalization strategy is essential for unambiguous parameter extraction and useful to quantify the influence of each model parameter.

Thin-film solar cells are widely recognised to have the potential to compete with fossil fuels in the electricity market due to their low cost per peak Watt. The Thin-Film Group at the University of New South Wales (UNSW) is engaged in developing polycrystalline silicon (poly-Si) thin-film solar cells on glass using e-beam evaporation technology. We believe our solar cells have the potential of significantly lowering the manufacturing cost compared to conventional, PECVD-fabricated thin-film solar cells. After years of materials research, the focus of the Group??s work is now moving to the metallisation of evaporated solar cells. Minimising various kinds of losses is the main challenge of the cell metallisation procedure, within which the contact resistance is always a big issue. In this thesis, the contact resistance of aluminium contacts on poly-Si thin-film solar cells on glass is investigated. To the best of the author??s knowledge, this is the first ever contact resistance investigation of Al contacts on evaporated poly-Si material for photovoltaic applications. Various transmission line models (TLM) are employed to measure the contact resistance. An improved TLM model is developed to increase the measurement precision and, simultaneously, to simplify the TLM pattern fabrication process. In order to accommodate the particular requirements of poly-Si coated glass substrates, a TLM pattern fabrication process using photolithography is established. Furthermore, a Kelvin sense tester is set up to ensure an accurate measurement of the contact resistance. After establishment of the TLM technique at UNSW, it is successfully tested on singlecrystalline silicon wafer samples. The thermal annealing process of the contacts is also optimised. Then, the general behaviour of Al contacts on uniformly doped poly-Si films (i.e., no p-n junction) is investigated using the verified TLM technique. The long-term stability of the contacts is also studied. This is followed by an investigation of the contact resistance of the back surface field and emitter layers of different types of poly-Si thin-film solar cells. Finally, a novel contact resistance measurement model is proposed that is believed to be able to overcome the measurement bottleneck of the transmission line models.

Orientador: Sérgio Kurokawa / Resumo: O objetivo deste projeto é desenvolver um modelo de linha de transmissão que leva em conta as principais características exigidas de um modelo deste componente do sistema elétrico, ou seja, ser desenvolvido diretamente no domínio do tempo, considerar que os parâmetros da linha são distribuídos ao longo de seu comprimento e levar em conta que os parâmetros longitudinais variam em função da frequência. O modelo proposto é baseado no modelo de Bergeron, que é um modelo de linha de transmissão desenvolvido diretamente no domínio do tempo e que leva em conta que os parâmetros de uma linha de transmissão são distribuídos ao longo de seu comprimento. No modelo proposto será levado em consideração que, devido aos efeitos solo e pelicular, os parâmetros longitudinais da linha (resistência longitudinal e indutância longitudinal) são variáveis em relação à frequência. Estes parâmetros serão aproximados por funções racionais e inseridos no modelo de Bergeron. O modelo desenvolvido será utilizado para representar linhas curtas e longas em simulações de transitórios eletromagnéticos resultantes de operações de manobras e de incidências de descargas atmosféricas. Por ser desenvolvido diretamente no domínio do tempo, o modelo proposto pode ser facilmente inserido em aplicativos do tipo ATP (Alternative Transients Program) e será uma ferramenta útil em simulações e análises de transitórios eletromagnéticos em sistemas de energia elétrica. / Abstract: The main objective of our project is to develop a transmission line model that takes into account the main characteristics demanded by a model of this electrical system component, i.e., be developed directly in the time-domain, consider the distributed nature of the line parameters and take into account the frequency dependence of the longitudinal parameters. The proposed model is based on the Bergeron model, which is a transmission line model directly developed in the time domain that takes into account that the transmission line parameters are distributed along its length. In the proposed model it will be taken into account that, due to earth-return effect and skin impedance, the longitudinal parameters (longitudinal resistance and longitudinal inductance) vary in relation to the frequency. These parameters will be approximated by rational functions and will be added to the Bergeron model. The developed model will be used to represent short and long transmission lines in simulations resulting from switching operations and lightning strikes. Because of the model being directly developed in the time-domain, the proposed model can be easily implemented in programs ATP-like (Alternative Transients Program) and will be a useful tool in power system transient analysis. / Doutor