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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Study on RF Sputtering system

Chang, Ying-Che 25 July 2008 (has links)
In this study, the RF sputtering system has been investigated comprehensively. Firstly, the relationship among the thickness of dark space, DC bias and electrode area under RF discharge is discussed. The impedance matching network of RF sputtering system, the configuration of glow discharge and their related electrical parameters are introduced and illustrated. The network theorem is used to calculate the loading impedance of RF sputtering system and to design an impedance matching circuit. And then the equivalent circuit of sheath and plasma in parallel plate RF discharge is analyzed. The characteristics of gas discharge of RF sputtering system are discussed, which includes the capacitance, resistance and conductivity on different pressure and magnetic field. Due to RF sputtering system usually driven at 13.56 MHz (this is an open frequency), we also considered how to avoid the radio frequency interference. In addition, the electrical characteristics of parallel plate RF discharge are revealed under argon atmosphere, and some of the general relationships between the various measured and determined parameters are also described. Finally, the difference between real system and ideal system are reported, and how to design a system which is rugged and reliable and can be operated, literally, in ¡¨push-button¡¨fashion, has been described in detail.
2

Pohybový senzor s identifikací / Motion sensor with identification

Halbich, Václav January 2013 (has links)
The solution of the motion detection system with the parallel radio identification on the same channel/carrier. The work is based on the RF sensor from ALPS Electric (product still in development phase), which works as an RF motion sensor and a digital transceiver as well. System can differenitiate general moving object from an object with active key. First part of this work describes the sensor module and the internal Nordic nRF24LE1 transciever (physical layer). Design of packet based communication protocol which does not influence motion sensing (communication layer) is discussed. Next part consist of FW design of application and identification protocol for sensor and key (application layer) and reference HW design of the active key. There are series of tests in every section.
3

A superconducting RF deflecting cavity for the ARIEL e-linac separator

Storey, Douglas W. 13 March 2018 (has links)
The ARIEL electron linac is a 0.3MW accelerator that will drive the production of rare isotopes in TRIUMF's new ARIEL facility. A planned upgrade will allow a second beam to be accelerated in the linac simultaneously, driving a Free Electron Laser while operating as an energy recovery linac. To not disrupt beam delivery to the ARIEL facility, an RF beam separator is required to separate the interleaved beams after they exit the accelerating cavities. A 650MHz superconducting RF deflecting mode cavity has been designed, built, and tested for providing the required 0.3MV transverse deflecting voltage to separate the interleaved beams. The cavity operates in a TE-like mode, and has been optimized through the use of simulation tools for high shunt impedance with minimal longitudinal footprint. The design process and details about the resulting electromagnetic and mechanical design are presented, covering the cavity's RF performance, coupling to the operating and higher order modes, multipacting susceptibility, and the physical design. The low power dissipation on the cavity walls at the required deflecting field allows for the cavity to be fabricated using non-conventional techniques. These include fabricating from bulk, low purity niobium and the use of TIG welding for joining the cavity parts. A method for TIG welding niobium is developed that achieves minimal degradation in purity of the weld joint while using widely available fabrication equipment. Applying these methods to the fabrication of the separator cavity makes this the first SRF cavity to be built at TRIUMF. The results of cryogenic RF tests of the separator cavity at temperatures down to 2K are presented. At the operating temperature of 4.2K, the cavity achieves a quality factor of 4e8 at the design deflecting voltage of 0.3MV. A maximum deflecting voltage of 0.82MV is reached at 4.2K, with peak surface fields of 26MV/m and 33mT. The cavity's performance exceeds the goal deflecting voltage and quality factor required for operation. / Graduate
4

RF-modul / RF-Module

Jönsson, Kristin January 2006 (has links)
Idén med examensarbetet var att konstruera en generell radiolänk med minsta möjliga storlek, som skulle kopplas samman med en redan befintlig konstruktion. Radiokrets CC1100 från Chipcon används tillsammans med mikroprocessor MSP430 från Texas Instruments. För att radiomodulen skall klara ett stort inspänningsområde används en spänningsstabilisator XC6202 från Torex. Det färdiga kortet är ett fyralagerskort med komponenter på en sida, med ett helt jordplan. Komponenterna är placerade så att de fyller sin funktion, samtidigt som de upptar minsta möjliga utrymme egentligen kanske detta med ska vara dåtid? . Med hjälp av en nätverksanalysator undersöktes antennanpassningen så att denna erhöll ett värde på nära 50 W. Radiokretsen programmerades och testades sedan. / The idea behind this project was to construct a general RF-module as small as possible and the RF-module should be able to connect to an existing design. A transceiver from Chipcon, CC1100, was used together with a microprocessor MSP430 from Texas Instruments. To make the RF-module handle a wide input voltage range a voltage regulator, XC6202, from Torex was used. The circuit board is a four layer card with one layer ground and components on one side. The components are placed to full fill there purpose and at the same time make the card as small as possible. With help from a network analyzer the network to the antenna was examined so it obtained a value near 50 W. The RF-module was programmed and tested with good result, but I didn’t participated.
5

The influence of breathing disorders on face shape : a three-dimensional study

Alali, Ala January 2013 (has links)
Breathing disorders can potentially influence craniofacial development through interactions between the respiratory flow and genetic and environmental factors. It has been suggested that certain medical conditions such as persistent rhinitis and renal insufficiency may have an influence on face shape. The effects of these conditions are likely to be subtle; otherwise they would appear as an obvious visible facial feature. The use of three-dimensional imaging provides the opportunity to acquire accurate and high resolution facial data to explore the influence of medical condition on facial morphology. Therefore, the aim of the present study is to investigate the influence of breathing disorders (asthma, atopy, allergic rhinitis and sleep disordered breathing) on face shape in children. The study sample, comprising of 4784 British Caucasian children of which 2922 (61.1%) were diagnosed with a breathing disorder, was selected from the Avon Longitudinal Study of Parents and Children (ALSPAC), which had been conducted to investigate the genetic and environmental determinants of development, health and disease. Three-dimensional surface laser scans were conducted on the children when they were 15 years old. A total of 21 reproducible facial landmarks (x, y, z co-ordinates) were identified. Average facial shells were constructed for each of the different disease groups and compared to facial shells of healthy asymptomatic children. Face-shape variables (angular and linear measurements) were analysed with respect to the different breathing disorders by employing a variety of statistical methods, including t-tests, chi-square tests, principal component analysis, binary logistic regression and analysis of variance (ANOVA). The results reveal that individual breathing disorders have varying influences on facial features, including increased anterior lower face height, a more retrognathic mandible and reduced nose width and prominence. The study also shows that the early removal of adenoids and tonsils can have a significant effect on obstructive breathing, resulting in the restoration of the facial morphology to its normal shape. This was particularly evident in children with normal BMIs. Surprisingly, no significant differences in face shape were detected in children with multiple diseases (combinations of asthma, allergic rhinitis, atopy and sleep-disordered breathing) when compared to healthy children. This may indicate the multifactorial, complex character of this spectrum of diseases. The findings provide evidence of small but potentially real associations between breathing disorders and face shape. This was largely attributable to the use of high-resolution and reproducible three-dimensional facial imaging alongside a large study sample. They also provide the scientific community with a detailed and effective methodology for static facial modelling that could have clinical relevance for early diagnosis of breathing disorders. Furthermore, this research has demonstrated that the ALSPAC patient archive offers a valuable resource to clinicians and the scientific community for investigating associations between various breathing disorders and face shape.
6

Radio-frequency coil design for magnetic resonance imaging and spectroscopy

Cassidy, Paul Joseph January 2002 (has links)
No description available.
7

Anatomy of the transmastoid endolymphatic sac decompression in the management of Ménière’s disease

Locke, Richard R. January 2008 (has links)
Ménière’s disease affects 1 in 1000 people and produces vertigo and hearing loss (Morrison, 1981). Endolymphatic sac decompression has been advocated on the basis that endolymphatic hydrops is the underlying pathology. The endolymphatic sac is said to be the terminal dilatation of the membranous labyrinth. It has been proposed that endolymph flows from the semicircular canals and cochlea to the endolymphatic sac. Portman (1927) devised a procedure for ‘decompressing’ the endolymphatic sac by removal of the bone from the posterior cranial fossa to relieve the symptoms of Ménière’s disease. Surgery on the endolymphatic sac remains controversial. Shea (1979) and Bagger-Sjöbäck et al (1990, 1993) have studied the endolymphatic sac using different techniques. There are discrepancies in the results between the two studies. The hypothesis that the endolymphatic sac can be safely approached and decompressed by a transmastoid route was tested. A total of thirteen cadaver heads and ten isolated temporal bones were used. A series of dissections were performed to examine the endolymphatic sac, perform measurements and analyse surgical approaches to the sac. Histological and electron microscopic study were performed. The lumen of the endolymphatic sac was not always identifiable in the dura of the posterior cranial fossa or it frequently lay over the sigmoid sinus. In the dura of the posterior cranial fossa where the endolymphatic sac is located was a thickening of the dura. This thickening was present even in the absence of the endolymphatic sac. The endolymphatic sac can be safely approached by a transmastoid approach, if there is an extraosseous component to the endolymphatic sac. The proximal endolymphatic sac can be approached by posterior cranial fossa route.
8

Indirect Analog / RF IC Testing : Confidence & Robusteness improvments / Test Indirect des circuits analogique et RF : Contribution pour une meilleur précision et robustesse

Ayari, Haithem 12 December 2013 (has links)
The conventional approach for testing RF circuits is specification-based testing, which involves verifying sequentially all specification requirements that are promised in the data sheet. This approach is a long-time effective testapproach but nowadays suffers from significant drawbacks.First, it requires generation and capture of test signals at the DUT operating frequency. As the operational frequencies of DUT are increasing, it becomes difficult to manage signal generation and capture using ATE. As a consequence, there is a need of expensive and specialized equipment. In addition,as conventional tests target several parameters, there is a need of several data captures and multiple test configurations. As a consequence, by adding settling time between each test and test application time, the whole test time becomes very long, and the test board very complex. Another challenge regarding RF circuit testing is wafer-level testing. Indeed, the implementation of specification-based tests at wafer level is extremely difficult due to probing issues and high parasitic effects on the test interface.Moreover, multi-site testing is usually not an option due to the small count of available RF test resources, which decreases test throughput. Hence, the current practice is often to verify the device specifications only after packaging.The problem with this solution is that defective dies are identified late in the manufacturing flow, which leads to packaging loss and decreases the global yield of the process.In order to reduce production costs, there is therefore a need to develop test solutions applicable at wafer level, so that faulty circuits can be removed very early in the production flow. This is particularly important for dies designed to be integrated in Systems-In-Package (SIP).In this context, a promising solution is to develop indirect test methods. Basically, it consists in using DUT signatures to non-conventional stimuli to predict the result of conventional tests. The underlying idea is to learn during an initial phase the unknown dependency between simple measurements and conventional tests. This dependency can then be modeled through regression functions. During the testing phase, only the indirect measurements are performed and specifications are predicted using the regression model built in the learning phase.Our work has been focused on two main directions. First, we have explored the implementation of the alternate test method based on DC measurements for RF circuits and we have proposed a methodology to select the most appropriateset of DC parameters. Results from two test vehicles (a LNA using electrical simulations and a PA using real production data) indicate that the proposed methodology allows precise estimation of the DUT performances while minimizing the number of DC measurements to be carried out.Second, we have proposed a novel implementation of the alternate test strategy in order to improve confidence in alternate test predictions and to overcome the effect of limited training set sizes. The idea is to exploit model redundancy in order to identify, during the production testing phase, devices with suspect predictions; these devices are then are removed from the alternate test tierand directed to a second tier where further testing may apply. / The conventional approach for testing RF circuits is specification-based testing, which involves verifying sequentially all specification requirements that are promised in the data sheet. This approach is a long-time effective testapproach but nowadays suffers from significant drawbacks.First, it requires generation and capture of test signals at the DUT operating frequency. As the operational frequencies of DUT are increasing, it becomes difficult to manage signal generation and capture using ATE. As a consequence, there is a need of expensive and specialized equipment. In addition,as conventional tests target several parameters, there is a need of several data captures and multiple test configurations. As a consequence, by adding settling time between each test and test application time, the whole test time becomes very long, and the test board very complex.Another challenge regarding RF circuit testing is wafer-level testing. Indeed, the implementation of specification-based tests at wafer level is extremely difficult due to probing issues and high parasitic effects on the test interface.Moreover, multi-site testing is usually not an option due to the small count of available RF test resources, which decreases test throughput. Hence, the current practice is often to verify the device specifications only after packaging.The problem with this solution is that defective dies are identified late in the manufacturing flow, which leads to packaging loss and decreases the global yield of the process.In order to reduce production costs, there is therefore a need to develop test solutions applicable at wafer level, so that faulty circuits can be removed very early in the production flow. This is particularly important for dies designed to be integrated in Systems-In-Package (SIP).In this context, a promising solution is to develop indirect test methods. Basically, it consists in using DUT signatures to non-conventional stimuli to predict the result of conventional tests. The underlying idea is to learn during an initial phase the unknown dependency between simple measurements and conventional tests. This dependency can then be modeled through regression functions. During the testing phase, only the indirect measurements are performed and specifications are predicted using the regression model built in the learning phase.Our work has been focused on two main directions. First, we have explored the implementation of the alternate test method based on DC measurements for RF circuits and we have proposed a methodology to select the most appropriateset of DC parameters. Results from two test vehicles (a LNA using electrical simulations and a PA using real production data) indicate that the proposed methodology allows precise estimation of the DUT performances while minimizing the number of DC measurements to be carried out.Second, we have proposed a novel implementation of the alternate test strategy in order to improve confidence in alternate test predictions and to overcome the effect of limited training set sizes. The idea is to exploit model redundancy in order to identify, during the production testing phase, devices with suspect predictions; these devices are then are removed from the alternate test tierand directed to a second tier where further testing may apply.
9

UWB Characteristics of RF Propagation for Body Mounted and Implanted Sensors

Chen, Jin 29 April 2013 (has links)
Body Area Network (BAN) technology is related to many applications inside, on and around the human body. The basic configuration of a BAN is a set of sensors, which are wearable or are placed inside the human body, transmitting signals to a terminal situated in a doctor’s office, in order to assess or monitor some aspect of a patient’s physical condition. Additionally, in many BAN applications the information about the sensor location is very important, since without knowing a sensor’s location, the transmitted data may be of limited value. As an example, Wireless Video Capsule Endoscopy (VCE) can benefit greatly from the addition of location information. The capsule transmits an RF signal from inside the human body to another sensor on the body surface or external. From the image data provided by the capsule, taken together with the location information, the doctor can locate the infection or lesion and initiate appropriate medical care. In this way, the treatment can be more effective and accurate. In this thesis we investigate the characteristics of Ultra-Wide Band (UWB) RF propagation for BAN devices placed around and inside the human body. We have made measurements around the human body and around a water-filled phantom using an E8363B Vector Network Analyzer (VNA), specifically measuring the S21 signal, which gives the transfer function. Based on these measurement results, we discuss the channel propagation for cases where the transmitter and the receiver are on the surface of the body and analyze the UWB propagation characteristics for RF localization. Because it is impractical or even impossible to make measurements inside the human body, we chose to apply the measurements using a simulation model of homogenous tissue, which serves as an approximation of the signal propagation environment inside the body. First, by comparing the multipath situation in free space and within a model of homogenous tissue, we are able to analyze the multipath effects inside human body. Then, because of the different characteristics of RF propagation in different bandwidths, we have made measurements at UWB (3GHz to 10GHz), and narrowband (402MHz) frequencies.
10

Observação em-circuito de distorção de um amplificador RF

Veiga, Ricardo Arieira January 2009 (has links)
Tese de mestrado integrado. Engenharia Electrotécnica e de Computadores (Major Telecomunicações). Faculdade de Engenharia. Universidade do Porto. 2009

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