Transparent thin film transistors fabricated at room temperature by radio frequency magnetron sputtering using indium oxide material system were proposed. The electrodes of the transparent thin film transistors were obtained by depositing indium oxide with 10% tim doping. Resistivity as low as 4¡Ñ10-4£[-cm at room temperature was achieved. The channel layers of the transparent thin film transistors were fabricated using pure indium oxide target in an Argon and oxygen environment. Resistivity larger than 10-5£[-cm was obtained with 60% oxygen partial pressure. Silicon nitride prepared by room temperature radio frequency sputtering were used for the gate dielectric layer with low leakage current. Environmental-safe lift-off processes were used to fabricated the electrodes, the isolation layer, and the channel layer. The transistor characteristics were obtained by standard I-V measurement. The on-off ratio of the 30£gm ¡Ñ 150£gm transparent thin film transistor is 100.

In this paper,we used Finite-Difference Time-Domain Method to Analyze CPW and Antenna.In CPW ,we had to process excitiation source and ABC.Or we couldn`t get correct result.In antenna analysis,we used KSIR to calculate antenna pattern.

The current techniques and methodologies used in the field of material characterization are well documented and widely accepted as reliable and accurate. However, literature describing these techniques focuses on the algorithms used during material characterization; few studies have reposted on the design of, and the selection criteria for, the test fixtures themselves. This research focuses on the measurement cell with the goal of determining the sensitivity of the measurement cell to the addition of a thin film material. Microstrip and coplanar waveguide were chosen for the analysis, which included three configurations of each transmission line geometry: a reference with no additional thin film material, one with the thin film on top of the conductors and one with the thin film beneath the conductors but on top of the transmission line substrate. The scattering parameters for the reference cell are compared to the scattering parameters of the test cell with the thin film material. The additional thin film material changes the effective dielectric constant of the reference cell; this change is evident in the phase and amplitude of S21. The optimum measurement cell is the one that experiences the greatest change to the effective dielectric constant with the addition of the thin film. Thus the greatest difference in S21 between the reference cell and the test cell is indicative of the reference cell's sensitivity. The figure of merit (FOM) to determine the structure's sensitivity is the integration over frequency of the magnitude of the vector difference of S21. The analysis shows that the double-layered CPW measurement cell was the most sensitive. Once the optimum structure was determined an analysis of the sensitivity of the FOM to changes in the physical and electrical properties of the reference structure was conducted. The most important factors in the selection of the reference cell as evident by the FOM's sensitivity are the substrate to thin film dielectric constant ratio and the CPW conductor aspect ratio to the thin film thickness. In particular, thinner films require a smaller conductor gap while wider gaps are preferable for thicker films. Measurement of four different CPW geometries, each covered in a 300 micron Polydimethylsiloxane thick film, validate the analysis process. The measurement cells differ in the conductor aspect ratio. The values of the measured FOMs trend as predicted by the simulation analysis.

This work presents the development of an in-plane vertical micro-coaxial probe using bulk micromachining technique for high frequency material characterization. The coaxial probe was fabricated in a silicon substrate by standard photolithography and a deep reactive ion etching (DRIE) technique. The through-hole structure in the form of a coaxial probe was etched and metalized with a diluted silver paste. A co-planar waveguide configuration was integrated with the design to characterize the probe. The electrical and RF characteristics of the coaxial probe were determined by simulating the probe design in Ansoft’s High Frequency Structure Simulator (HFSS). The reflection coefficient and transducer gain performance of the probe was measured up to 65 GHz using a vector network analyzer (VNA). The probe demonstrated excellent results over a wide frequency band, indicating its ability to integrate with millimeter wave packaging systems as well as characterize unknown materials at high frequencies. The probe was then placed in contact with 3 materials where their unknown permittivities were determined. To accomplish this, the coaxial probe was placed in contact with the material under test and electromagnetic waves were directed to the surface using the VNA, where its reflection coefficient was then determined over a wide frequency band from dc-to -65GHz. Next, the permittivity of each material was deduced from its measured reflection coefficients using a cross ratio invariance coding technique. The permittivity results obtained when measuring the reflection coefficient data were compared to simulated permittivity results and agreed well. These results validate the use of the micro-coaxial probe to characterize the permittivity of unknown materials at high frequencies up to 65GHz.

<p> A review of movie projection principles and techniques as applied to conventional projectors and a description of general features, mechanism and film movement of the Rolling Loop Projector are presented.</p> <p> The characteristics of a film loop under static conditions with coplanar clamping planes are investigated in terms of loop shape, supporting forces and bending moments. An extension of this analysis is applicable to the case when the loop is fixed on a curved surface.</p> <p> The motion of a loop in the projector is simulated as it grows and rolls on a flat surface and a numerical technique is employed to find the point paths and the velocity and acceleration vectors of these points on the loop at various instants in a projection cycle.</p> <p> Some design criteria are derived from an examination of the results, and these are presented.</p> / Thesis / Master of Engineering (MEngr)

No description available.

No / In this paper, low profile planar Metamaterial-Inspired coplanar fed waveguide antenna is presented for WLAN and Ultra-Wideband applications. The antenna is based on a simple strip loaded to a rectangular patch and zigzag E-shape metamaterial-inspired unit cell. The idea behind the proposed antenna is to enable miniaturization effect. The proposed antenna can provide dual band operation, the first one is a Wi-Fi band at 2.45 GHz having impedance bandwidth of 150MHz, the second one is an ultra wide band extended from 4.2 GHz to 6.5 GHz. Two antennas are designed and fabricated with and without metamaterial-inspired loading. The simulated and measured results regarding Return loss (S11), Gain and Radiation pattern are discussed.

High performance RF/mixed signal systems require new interconnect strategies to combine high frequency (microwave/mm-wave) circuitry with silicon mixed-signal and baseband digital processing. In such systems, heterogeneous vertical integration, in which circuits in different technologies can be stacked on top of each other within the system architecture, can reduce the overall system size and power consumption. Chip stacking also enables optimally-performing heterogeneous systems, because each level of the stack can consist of components fabricated in their most suited device or substrate technology. Two novel approaches for the vertical interconnection of heterogeneous integrated systems are proposed in this work. These approaches are related to flip-chip bonding techniques used in Radio-Frequency (RF)/microwave integrated circuits. The first proposed approach involves an interlocking mechanical structure that supports flip-chip assembled Monolithic Microwave Integrated Circuits (MMICs). Photolithographically patterned thick-film SU-8 structures are applied to both the chip and the carrier such that the chip self-aligns into place and mates with the carrier. Gold bumps embedded within the structures electrically connect the chip pads to the carrier pads. This method is demonstrated through the assembly of a SiGe power amplifier MMIC onto a high resistivity silicon carrier. The second proposed approach involves vertical interconnects consisting of room temperature liquid-state metals. The fluid nature of the liquid bumps allows them to be robust in the presence of thermo-mechanical stresses, such as Coefficient of Thermal Expansion (CTE) mismatch between the interconnected chips. SU-8 structures are used to form a shaping mold on the bottom carrier that contains the liquid metal. Gold posts are electroplated on the top chip, then mated with the SU-8 mold, thereby making contact with the liquid metal to form the electrical continuity. For each of these proposed methods, design and fabrication considerations are discussed in detail. RF measurements on prototype structures up to Ka band are performed to verify the functionality of the proposed methods. Given the results of these proof-of-concept efforts, electrical characteristics of the materials used in these methods are determined, and recommendations are provided for future improvements and refinements to these two techniques. / Master of Science

The objectives of this work were to investigate, design and implement beam steering antenna arrays for mobile and wireless applications using the genetic algorithm (GA) and particle swarm optimisation (PSO) techniques as optimisation design tools. Several antenna designs were implemented and tested: initially, a printed dipole antenna integrated with a duplex RF switch used for mobile base station antenna beam steering was investigated. A coplanar waveguide (CPW) to coplanar strip (CPS) transition was adopted to feed the printed dipole. A novel RF switch circuit, used to control the RF signal fed to the dipole antenna and placed directly before it, was proposed. The measured performance of the RF switch was tested and the results confirmed its viability. Then two hybrid coupled PIN diode phase shifters, using Branchline and Rat-Race ring coupler structures, were designed and tested. The generation of four distinct phase shifts was implemented and studied. The variations of the scattering parameters were found to be realistic, with an acceptable ±2 phase shift tolerance. Next, antenna beam steering was achieved by implementing RF switches with ON or OFF mode functions to excite the radiating elements of the antenna array. The switching control process was implemented using a genetic algorithm (GA) method, subject to scalar and binary genes. Anti-phase feeding of radiating elements was also investigated. A ring antenna array with reflectors was modelled and analysed. An antenna of this type for mobile base stations was designed and simulation results are presented. Following this, a novel concept for simple beam steering using a uniform antenna array operated at 2.4 GHz was designed using GA. The antenna is fed by a single RF input source and the steering elements are reactively tuned by varactor diodes in series with small inductors. The beam-control procedure was derived through the use of a genetic algorithm based on adjusting the required reactance values to obtain the optimum solution as indicated by the cost function. The GA was also initially used as an optimisation tool to derive the antenna design from its specification. Finally, reactive loading and time modulated switching techniques are applied to steer the beam of a circular uniformly spaced antenna array having a source element at its centre. Genetic algorithm (GA) and particle swarm optimisation (PSO) processes calculate the optimal values of reactances loading the parasitic elements, for which the gain can be optimised in a desired direction. For time modulated switching, GA and PSO also determine the optimal on and off times of the parasitic elements for which the difference in currents induced optimises the gain and steering of the beam in a desired direction. These methods were demonstrated by investigating a vertically polarised antenna configuration. A prototype antenna was constructed and experimental results compared with the simulations. Results showed that near optimal solutions for gain optimisation, sidelobe level reduction and beam steering are achievable by utilising these methods. In addition, a simple switching process is employed to steer the beam of a horizontally polarised circular antenna array. A time modulated switching process is applied through Genetic Algorithm optimisation. Several model examples illustrate the radiation beams and the switching time process of each element in the array.

[pt] Há uma crescente demanda pela criação de modelos computacionais representativos de objetos reais para projetos de engenharia. Uma alternativa barata e eficaz consiste na utilização de técnicas de Visão Computacional baseada em câmeras e projetores disponíveis no mercado de computadores pessoais. Este trabalho avalia um sistema óptico estéreo ativo para capturar formas geométricas de objetos utilizando um par de câmeras e um projetor digital. O sistema se baseia em idéias de trabalhos anteriores, com duas contribuições nesta dissertação. A primeira é uma técnica mais robusta de detecção de pontos notáveis em padrões de calibração das câmeras. A segunda contribuição consiste num novo método de ajuste de cilindros que visa aplicar o sistema estudado na inspeção de instalações de dutos industriais. As conclusões apresentadas procuram avaliar a robustez e precisão do sistema proposto como um instrumento de medidas em Engenharia. / [en] There has been a growing demand for creation of computer models based on real models for engineering projects. A cheap and effective alternative consists in using Computer Vision techniques based on cameras and projectors available at the personal computer market. This work evaluates a stereo optic system for capturing geometric shapes from objects using a pair of cameras and a single digital projector. The system is based on former works and a pair of contributions is obtained at this dissertation. The first contribution is a more robust technique for finding corners and points at cameras calibration patterns. And the second one consists on a new method for cylinder fit for inspecting industrial piping facilities with the studied system. The final conclusions evaluate the robustness and precision from the proposed system as a measurement tool for Engineering.