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InAs/GaSb quantum well structures of Infrared Detector applications. : Quantum well structureMahajumi, Abu Syed January 2010 (has links)
<p>The detection of MWIR (mid wavelength infrared radiation) is the important for industrial, biomedical and military applications.desirable for the radiation detector to operate in the middle wavelength IR (MWIR) band corresponding to a wavelength band ranging from about 3 microns to about 5 microns.Such MWIR detectors allow forobjects having a similar thermal signature. In addition, MWIR detectors may be used in low power applications such as in night vision for surveillance of personnel.</p><p>Now a day commercially available uncooled IR sensors operating in MWIR region (2 – 5 μm) use microbolometric detectors which are inherently slow. The novel detector of InAs/GaSb quantum well structures overcomes this limitation. However, third-generation high-performance IR FPAs are already an attractive proposition to the IR system designer. They covered such as multicolour (at least two, and maybe more different spectral bands) with the possibility of simultaneous detection in both space and time, and ever larger sizes of, say, 2000 × 2000, and operating at higher temperatures, even to room temperature, for all cut-off wavelengths.These hetero structures have a type-II band alignment such that the conduction band of InAs layer is lower than the valence band of GaSb layer. The effective bandgap of thesestructures can be adjusted from 0.4 eV to values below 0.1 eV by varying the thickness of constituent layers leading to an enormous range of detector cutoff wavelengths (3-20 This work is focused on the various key characteristics the optical (responsivity and detectivity) and electrical (surface leakage & dark current) of infrared detector and proof of concept is demonstrated on infrared P-I-N photodiodes based on InAs/GaSb superlattices with ~8.5 μm cutoff wavelength and bandgap energy ~150 meV operating at 78 K where supression of surface leakage currents is observed. In certain military applications, it isthermal imaging of airplanes, artillery tanks and otherμm).</p> / Nice research work at Halmstad University
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Sensorsystem till hinderhanterande robot / Sensor System for Obstacle Handling RobotLichtermann, Johan January 2005 (has links)
<p>The projects goal is to construct and program a robot that is controlled from a computer but also have an obstacle handling function that allows the robot to navigate around the object by itself.</p><p>The robot is a simple construction and the number of components and functions is kept at a minimum. A tricycle construction was chosen because it’s the simplest. Communication between the robot and the computer also kept as simple as possible.</p> / <p>Målet med projektet är att konstruera och programmera en robot som går att styra från en dator men det skall även finnas en hinderhanterande funktion som gör att roboten kan åka runt hinder av sig själv.</p><p>Roboten är en enkel konstruktion där antalet komponenter och funktioner hålls nere till ett minimum. En trehjuling valdes då det är den enklaste konstruktionen. Kommunikationen mellan roboten och datorn hålls också så enkel som möjligt.</p>
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Position Sensitive Detectors : Device Technology and Applications in SpectroscopyAndersson, Henrik January 2008 (has links)
This thesis deals with the development, processing and characterization of position sensitive detectors and, in addition, to the development of compact and cost effective spectrometers. Position sensitive detectors are used to measure, with great accuracy and speed, the position of a light spot incident on the surface. Their main use is for triangulation, displacement and vibration measurements. A type of position sensitive detector based on the MOS principle and using optically transparent indium tin oxide as a gate contact has been developed. This type of detector utilizes the MOS principle where an induced channel forms beneath the gate oxide in the surface of the Silicon substrate. One and two dimensional detectors have both been fabricated and characterized. The first measurements showed that the linearity did not fulfil expectations and it was suspected that stress induced by the gate contact could be the reason for the seemingly high nonlinearity. Further investigations into both the p-n junction and the MOS type position sensitive detectors lead to the conclusion that the indium tin oxide gate is responsible for inducing a substantial stress in the surface of the detector, thus giving rise to increased position nonlinearity. The heat treatment step which was conducted was determined to be critical as either a too short or too long heat treatment resulted in stress in the gate and channel leading to position nonlinearity. If a correctly timed heat treatment is performed then the detector’s linearity is in parity with the best commercial position sensitive detectors. In addition, the development of very small, compact and cost effective spectrometers has been performed with the aim of constructing devices for use in the process industry. The development of a wedge shaped array of Fabry-Perot interferometers that can be mounted directly on top of a detector makes it possible to construct a very compact spectrometer using the minimum amount of optics. This wedge interferometer has been evaluated by means of array pixel detectors and position sensitive detectors for both the infrared and the visible wavelength ranges. When used with a position sensitive detector it is necessary to use a slit to record the intensity of the interferogram for many points over the detector, equivalent to pixels on an array detector. Usually the use of moving parts in a spectrometer will impose the use of high precision scanning mechanisms and calibration. By using a position sensitive detector for the interferogram readout both the position and the intensity are known for every measurement point and thus the demands placed on the scanning system are minimized. / Denna avhandling behandlar utveckling, processning och karakterisering av positionskänsliga detektorer och även utveckling av kompakta, kostnadseffektiva spektrometrar. Positionskänsliga detektorer används för att mäta positionen av en infallande ljuspunkt på ytan med hög noggrannhet och hastighet. Det huvudsakliga användningsområdet är triangulering, förskjutnings och vibrationsmätningar. En typ av positionskänslig detektor baserad på MOS principen och som använder optiskt transparent indium-tenn-oxid som ”gate” kontakt har utvecklats och karakteriserats. Denna typ av detektor utnyttjar MOS principen där en inducerad kanal bildas under ”gate” oxiden i ytan på kiselsubstratet. Både en endimensionell och en tvådimensionell detektor har tillverkats och karakteriserats. De första mätningarna visade på att linjäriteten inte var den förväntade och det misstänktes att stress inducerad av ”gate” kontakten kunde vara orsaken till den tillsynes för höga ickelinjäriteten. Ytterligare undersökning på både p-n och MOS positionskänsliga detektorer ledde till slutsatsen att indium-tenn-oxid ”gate” kontakten är ansvarig för att orsaka en väsentlig stress i ytan på detektorn och därigenom orsaka ökad olinjäritet i positionsbestämningen. Värmebehandlingssteget som utförs fastställdes vara kritiskt där en för kort eller för lång värmebehandling resulterar i stress i ”gate” kontakten och kanalen som leder till olinjäritet. Om en korrekt värmebehandling utförs så är de tillverkade detektorernas linjäritet i paritet med de bästa kommersiella positionskänsliga detektorerna. Utveckling av väldigt små, kompakta och kostnadseffektiva spektrometrar har också utförts med målet att konstruera enheter för användning i process industrin. Utvecklingen av en kilformad ”array” av Fabry-Perot interferometrar som kan monteras direkt på en detektor gör det möjligt att konstruera en väldigt kompakt spektrometer med minimalt med optik. Denna kilformade interferometer har utvärderats med arraydetektorer, både för det infraröda och det synliga våglängdsområdet, och också med positionskänsliga detektorer. När den används med en positionskänslig detektor så är det nödvändigt att använda en springa att begränsa ljuset med för att registrera intensiteten av interferrogrammet i många punkter över detektorn, vilket är likvärdigt med pixlar på en arraydetektor. Vanligtvis gör användandet av rörliga delar i en spektrometer att mekanismer med hög precision och kalibrering måste användas. Genom att använda en positionskänslig detektor för att läsa ut interferrogrammet så kommer både positionen såväl som ljusintensiteten att vara känd i varje mätpunkt och därför minimeras kravet på förflyttningsmekanismen.
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Wireless ECGmediavilla pons, emiliano elias January 2009 (has links)
This document contains the development of an amplifier for an ECG-signal and interfacing it to wireless communication. The purpose of this project is to get a clear ECG-signal without any noise, save it and send it through wireless communication.A challenge of the wireless communication unit is to send as little information as possible to make the communication faster, without loss of information in the ECG-signal.The context for this project is the integration of wireless communication in medical applications for home healthcare. This means that, patients are no longer bound to a specific healthcare location where they are monitored by medical instruments. Wireless communication will not only provide them with safe and accurate monitoring, but also the freedom of movement.
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Sensorsystem till hinderhanterande robot / Sensor System for Obstacle Handling RobotLichtermann, Johan January 2005 (has links)
The projects goal is to construct and program a robot that is controlled from a computer but also have an obstacle handling function that allows the robot to navigate around the object by itself. The robot is a simple construction and the number of components and functions is kept at a minimum. A tricycle construction was chosen because it’s the simplest. Communication between the robot and the computer also kept as simple as possible. / Målet med projektet är att konstruera och programmera en robot som går att styra från en dator men det skall även finnas en hinderhanterande funktion som gör att roboten kan åka runt hinder av sig själv. Roboten är en enkel konstruktion där antalet komponenter och funktioner hålls nere till ett minimum. En trehjuling valdes då det är den enklaste konstruktionen. Kommunikationen mellan roboten och datorn hålls också så enkel som möjligt.
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Wireless ECGmediavilla pons, emiliano elias January 2009 (has links)
<p>This document contains the development of an amplifier for an ECG-signal and interfacing it to wireless communication. The purpose of this project is to get a clear ECG-signal without any noise, save it and send it through wireless communication.A challenge of the wireless communication unit is to send as little information as possible to make the communication faster, without loss of information in the ECG-signal.The context for this project is the integration of wireless communication in medical applications for home healthcare. This means that, patients are no longer bound to a specific healthcare location where they are monitored by medical instruments. Wireless communication will not only provide them with safe and accurate monitoring, but also the freedom of movement.</p>
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Modelling and Design of Oversampled Delta-Sigma Noise Sharpers for D/A ConversionParihar, Vikram Singh January 2005 (has links)
<p>This thesis demonstrates the high- level modelling and design of oversampled delta- sigma noise shapers for D/A conversion. It presents an overview and study on digital- to- analog converters (DAC) followed by the noise shapers. It helps us to understand how to design a noise shaper model and algorithmic expressions are presented. The models are verified through high level simulations. The usage of models is to reduce the design time and get a good understanding for fundamental limitations on performance. Instead of time consuming circuit- level simulations, we point out the behavioural- level and algorithmic- level simulations of the noise shaper and the entire system comprising of interpolation filter, noise shaper followed by pulse amplitude modulation and reconstruction filtering. We have used the delta- sigma modulators to reduce the number of bits representing the digital signal. It is found that the requirement on oversampled DACs are tough. It is emphasised that the design of an oversampling converter is a filter designproblem. There is a large number of trade- offs that can be made between the different building blocks in the OSDAC.</p>
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Active and Passive Unequally Spaced Reflect-Arrays and Elements of RF Integration TechniquesKurup, Dhanesh G. January 2003 (has links)
<p>Using an array synthesis tool based on a modified differential evolution algorithm, it is shown that the position-phase synthesis exhibits improved pattern characteristics compared to both the phase only and position only synthesis of uniform amplitude antenna arrays. The design of an unequally spaced planar reflect-array and an active power combining reflect-array are presented. The unit cell of the active reflect-array consists of an amplifying active reflect-antenna designed using a novel dual polarized microstrip-T coupled patch antenna. Two modelling approaches are proposed for the active reflect-antenna and the modelling methods are compared with the experiments.</p><p>A computationally efficient analysis of an H-slot in the ground plane of a microstripline is carried out using a transmission line model. To improve the accuracy in the resonant region of the H-slot and retaining the computational efficiency, an artificial neural network is combined with an efficient spectral domain method. An efficient analysis tool for a silicon micromachined H-slot coupled antenna is developed by combining the transmission line models of the H-slot and an aperture coupled antenna. The experimental results are compared with the theory showing good agreement.</p><p>The analysis and design of a microwave amplifier based on non-resonant slot matching is carried out. It is seen that the designed slot matched amplifier has decreased layout size, improved gain and noise figure characteristics compared to a stub matched amplifier. An efficient method for the analysis of non-resonant slots is compared with other approaches showing good agreement. This points to the fact that non-resonant slot matched circuits can be designed with the same speed and efficiency as we design the traditional stub based matching circuits.</p><p>To address the problem of bandwidth and performance of reflect-arrays we propose a dielectric resonator antenna with slotline stubs. As a preliminary step we design a dielectric resonator antenna with slotline feed and the experimental results are compared with those of a commercial CAD tool. Design and analysis of 3D interconnects based on non-radiative dielectric waveguides is carried out. At millimeterwave, these interconnects are useful for hybrid and multilayer integration techniques.</p>
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Active and Passive Unequally Spaced Reflect-Arrays and Elements of RF Integration TechniquesKurup, Dhanesh G. January 2003 (has links)
Using an array synthesis tool based on a modified differential evolution algorithm, it is shown that the position-phase synthesis exhibits improved pattern characteristics compared to both the phase only and position only synthesis of uniform amplitude antenna arrays. The design of an unequally spaced planar reflect-array and an active power combining reflect-array are presented. The unit cell of the active reflect-array consists of an amplifying active reflect-antenna designed using a novel dual polarized microstrip-T coupled patch antenna. Two modelling approaches are proposed for the active reflect-antenna and the modelling methods are compared with the experiments. A computationally efficient analysis of an H-slot in the ground plane of a microstripline is carried out using a transmission line model. To improve the accuracy in the resonant region of the H-slot and retaining the computational efficiency, an artificial neural network is combined with an efficient spectral domain method. An efficient analysis tool for a silicon micromachined H-slot coupled antenna is developed by combining the transmission line models of the H-slot and an aperture coupled antenna. The experimental results are compared with the theory showing good agreement. The analysis and design of a microwave amplifier based on non-resonant slot matching is carried out. It is seen that the designed slot matched amplifier has decreased layout size, improved gain and noise figure characteristics compared to a stub matched amplifier. An efficient method for the analysis of non-resonant slots is compared with other approaches showing good agreement. This points to the fact that non-resonant slot matched circuits can be designed with the same speed and efficiency as we design the traditional stub based matching circuits. To address the problem of bandwidth and performance of reflect-arrays we propose a dielectric resonator antenna with slotline stubs. As a preliminary step we design a dielectric resonator antenna with slotline feed and the experimental results are compared with those of a commercial CAD tool. Design and analysis of 3D interconnects based on non-radiative dielectric waveguides is carried out. At millimeterwave, these interconnects are useful for hybrid and multilayer integration techniques.
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Modelling and Design of Oversampled Delta-Sigma Noise Sharpers for D/A ConversionParihar, Vikram Singh January 2005 (has links)
This thesis demonstrates the high- level modelling and design of oversampled delta- sigma noise shapers for D/A conversion. It presents an overview and study on digital- to- analog converters (DAC) followed by the noise shapers. It helps us to understand how to design a noise shaper model and algorithmic expressions are presented. The models are verified through high level simulations. The usage of models is to reduce the design time and get a good understanding for fundamental limitations on performance. Instead of time consuming circuit- level simulations, we point out the behavioural- level and algorithmic- level simulations of the noise shaper and the entire system comprising of interpolation filter, noise shaper followed by pulse amplitude modulation and reconstruction filtering. We have used the delta- sigma modulators to reduce the number of bits representing the digital signal. It is found that the requirement on oversampled DACs are tough. It is emphasised that the design of an oversampling converter is a filter designproblem. There is a large number of trade- offs that can be made between the different building blocks in the OSDAC.
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