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1

MacLean, Douglas J. "Mobile source development for seismic-sonar based landmine detection." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Jun%5FMacLean.pdf.

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2

Starr, Paul. "Mobile bed interaction with a cylinder under currents and waves." Thesis, University of Manchester, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.680164.

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3

VARGAS, CARLOS EDUARDO ORIHUELA. "ANTENNA PROJECT AND IMPLEMENTATION FOR CHARACTERIZATION OF MOBILE RADIO CHANNEL IN MILLIMETER WAVES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=25606@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO<br>COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR<br>FUNDAÇÃO DE APOIO À PESQUISA DO ESTADO DO RIO DE JANEIRO<br>PROGRAMA DE EXCELENCIA ACADEMICA<br>O termo de ondas milimétricas refere-se à porção do espectro eletromagnético com frequências entre 30 e 300 GHz, correspondente a comprimentos de onda de 10 até 1 mm, respectivamente. As características das ondas milimétricas diferem das micro-ondas e das infravermelhas, e são estas diferenças que fazem com que um sistema de ondas milimétricas seja o candidato ideal para algumas aplicações. Nos anos passados, a falta e o alto custo de fontes, dispositivos, componentes e instrumentação adequada, para esta faixa de frequências, levaram a um progresso muito devagar nesta área, no entanto, as limitações dos sistemas infravermelhos e ópticos e a superlotação da região do micro-ondas do espectro ocasionaram um maior interesse em frequências milimétricas nos últimos anos. A quinta geração dos sistemas móveis deve estar pronta nos próximos anos, e muitas pesquisas estão se desenvolvendo nas faixas de 28 GHz, 38 GHz e 60 GHz. A faixa de 60 GHz, na qual as ondas têm uma maior atenuação comparada com as outras duas, oferece um maior espectro eletromagnético. Nesta faixa de frequência, as ondas se refletem muito e pode se aproveitar estas reflexões para uma melhor recepção sendo, por tanto, uma ótima opção para comunicação móvel de curta distância com altas taxas de transferência de dados. Para poder aproveitar a maior quantidade de multipercursos, a antena receptora deve ter uma largura de feixe grande. Assim, neste trabalho, duas antenas foram projetadas, construídas e, de alguma forma, testadas para uma frequência de 60 GHz, onde as larguras de feixe simuladas obtidas foram de 112 graus e 115 graus.<br>The millimeter wave term refers to that portion of the electromagnetic spectrum with frequencies between 30 and 300 GHz corresponding to wavelengths of 1 to 10 mm. The characteristics of the millimeter wave differ from microwave and infrared, and these differences make a millimeter wave system, an ideal candidate for some applications. In the past the lack and the high cost of supplies, devices, components and instrumentation suitable for this frequency band caused very rambling progress in this area. However, the limitations of infrared optical systems and overcrowding of the microwave spectrum region led to a greater interest in the millimeter frequency in recent years and it is expected an increase in this interest. The fifth generation of mobile systems should be ready in the coming years, and many studies are developing in the 28 GHz, 38GHz and 60GHz bands. In the 60 GHz band, waves has a higher attenuation compared to the other two, but also offers greater electromagnetic spectrum, in this band, waves has a lot of reflection, then, scattering can be taken for better reception. So, this band is a great choice for short distance mobile communication with high data rates. To get the greatest amount of multipath, the receiving antenna must have a wide beam width. In this work, two antennas were designed, built and somewhat tested for a frequency of 60 GHz for mobile environment, where the beam widths obtained are 112 degrees and 115 degrees.
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Lönn, Stefan. "Mobile phone use and risk of intracranial tumors /." Stockholm, 2004. http://diss.kib.ki.se/2004/91-7140-096-6/.

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5

Cracraft, Michael Andrew. "Mobile array designs with ANSERLIN antennas and efficient, wide-band PEEC models for interconnect and power distribution network analysis." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.umr.edu/thesis/pdf/mcthesis20070623_09007dcc80374999.pdf.

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Thesis (Ph. D.)--University of Missouri--Rolla, 2007.<br>Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 16, 2007) Includes bibliographical references (p. 134-136).
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6

Nasser, Najat. "Contribution to the study and minimizing the impact of electromagnetic waves on the human body : Application in the field of mobile telephony." Thesis, Limoges, 2018. http://www.theses.fr/2018LIMO0091/document.

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Dans cette thèse, nous proposons des modifications de conception d’antenne PIFA concernant la téléphonie mobile afin de réduire le taux de pénétration des ondes électromagnétiques dans la tête. Trois antennes ont été considérées: une antenne PIFA à bande unique fonctionnant à 1,8 GHz, une antenne PIFA à bande double fonctionnant à 900 MHz et à 1,8 GHz, et une antenne PIFA tri-bande à 900 MHz, 1800 MHz et 2400 MHz. La densité de courant de surface le long du plan de masse a été réduite en diminuant le rayonnement du champ électrique émis par l’antenne émettrice vers le corps, ce qui a entraîné une réduction de la densité de courant le long de la tête humaine ainsi que du SAR. Cette réduction du SAR a été réalisée en insérant plusieurs traitements de bords tels qu'une forme en U à chaque coin du plan de masse de l'antenne. Nous avons étudié trois types des antennes : la première, lorsque les bords U sont constitués de PEC, nous obtenons une réduction du SAR de 78,6%. La seconde utilise un type de liquide considéré comme absorbant. Avec ce liquide, deux antennes ont été analysées: une PIFA à bande unique fonctionnant à 1,8 GHz et une PIFA à bande double fonctionnant à 900 MHz et à1,8 GHz. Dans ce scénario, le bord en U est constitué d’eau, et nous avons constaté que la valeur maximale du SAR moyen sur 10 g de tissu était réduite à 73,52% pour une PIFA à bande unique, tandis que le pic de SAR a été réduit à 88,78% et 90,31% en cas de double bande. Afin de préserver la hauteur de l'antenne et de la rendre plus réaliste, un autre type d’antenne a été modélisé en insérant des arêtes en forme de U à chaque extrémité du plan de masse. Dans ce cas, la réduction du SAR a été la suivante: 74,5% à 1800 MHz pour une bande unique et environ 64,37%, 79,92% et 54,71% à 900 MHz, 1800 MHz et 2400 MHz pour une antenne tri-bande, et pour une moyenne de masse de tissu égale à 10g. Dans une dernière partie, cette thèse propose une antenne optimisée pour des transmissions de la station de base vers l'utilisateur d’un téléphone mobile, en exploitant la bande GSM-900. L’objectif principal de cette étude est de fournir une intensité de champ constante sur la surface de couverture, afin de minimiser certains effets biologiques considérés comme dangereux pour la santé humaine<br>In this thesis, we propose new types of mobile handset PIFA antenna design to reduce the specific absorption rate (SAR) in human head. Three antennas were considered: a single band PIFA operating at 1.8 GHz, a dual band PIFA operating at 900 MHz and 1.8 GHz, and a Triband PIFA operating at 900MHz, GSM 1800MHz, and 2400MHz. Surface current density along the ground plane was decreased by reducing the near electric field radiation coming from the radiating antenna to the human head, which in turns leads to a reduction in current density along human head as well as the SAR. This SAR reduction is accomplished by inserting several edges treatment such as U-shape at each corner of the ground plane of antenna. In this scenario, we studied three types: first one, when U-edges are made of PEC, we get SAR reduction about 78.6%. Second one is a liquid type that is considered as more advanced type. For this type, two antennas are considered: a single band PIFA operating at 1.8 GHz, and a dual band PIFA operating at 900 MHz and 1.8 GHz. In this scenario, two cases were studied: first one when the U-edge is made of water, we noticed that the peak SAR value averaged over 10 g mass tissue was reduced to 73.52% in the case of single band PIFA, whereas the peak SAR was reduced to 88.78% and 90.31% in case of dual band. Second case, when U-edge filled with water, this enhanced structure was presented to overcome the manufacturing limitations of the first case design. Simulation results showed a better performance in terms of reflection coefficient and radiation pattern for both single-band and dual-band antennas. The results of SAR were also similar to the first case structure design for the single-band antenna. However, the SAR was slightly higher for the dual-band antenna, but it still remains very low (1.6 W/Kg at 900 MHz and 0.6 W/Kg at 1800 MHz). After that, for preserving the height of antenna, and making it more realistic to be applied, another type was done by inserting U-edges above each corner of the ground plane. In this case, we get SAR reduction as follows: 74.5% at GSM1800MHz in case of single band, and about 64.37%, 79.92%, and 54.71% at GSM900MHz, GSM1800MHz, and 2400 MHz in case of Tri-band averaged over 10g mass tissue. On the other hand, this thesis presents a modern and unprecedented safety antenna that transmits from the base station to the mobile user being operated at the GSM-900 band. The main objective of this study is to provide a constant field strength or a uniform coverage over a certain surface area, for preventing human health from several hazardous biological effects, and this strongly depends on the studied site (e.g. if it is densely urban, rural, open area, etc.). Our proposed design is synthesized using S.A.R.A (Synthesis of Array of Antenna) software. Besides, Atoll GSM planning tool is used to ensure the signal coverage and power strength for the safety antenna, and CST (Computer Simulation Technology) software for simulating the proposed antenna
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7

Mastrosimone, Antonio Roberto. "Hybrid modile femtocells: the mmWave solution for 5G Moving Networks." Doctoral thesis, Università di Catania, 2017. http://hdl.handle.net/10761/3644.

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Mobile connectivity is a vital requirement for peoples everyday life. Users would like to have unlimited access to information for anyone, anywhere, and anytime, especially in public means of transport where they spend a lot of time travelling. The connectivity to Internet becomes difficult for passengers because public transportation vehicles suffer from the low quality signal from the outside wireless network. One of the requirements of the 5G Network is to guarantee a high level of service to users wherever they are, both at home, office, or in public means of transport. Users on the move shall have the impression that the network infrastructure follows them", in situations where they suffer from poor coverage today. A first solution to improve the broadband connectivity is to deploy more eNodeBs close to buses or train routes, but it requires high investment for providers and a higher complexity in managing the increasing number of handover. The rapid growth in the deployment of LTE femtocells for indoor use and their benefits have led many authors to propose using them even in vehicles, implementing the so-called Moving Networks. This work shows that the use of pure LTE mobile femtocells exhibits relevant issues in terms of interference and consequently poor performance in a realistic use. In order to overcome these issues, we propose to adopt the millimeter Wave (mmWave) technology in the Moving Networks, creating the Hybrid Mobile Femtocells. The new technology will satisfy the 5G requirements of enhancing the capacity and coverage for the users on the move and to enable long battery life, due to the short range transmission between the user equipments and the access point. In the thesis we discuss the concerns arising from applying mmWave communications at 60 GHz inside vehicles. We provide a new throughput analysis in order to benchmark our proposal to the solutions presented in literature. Furthermore, we analyse the system performance in two different scenarios: a sub-urban setup and in an urban configuration where different kind of cells are deployed. The results obtained by Matlab simulations, show a noticeable improvement of the global system throughput by using Hybrid Mobile Femtocells.
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8

Swanson, Joshua G. Cowell Charles Mark. "A test of differential GPS correction methods at Fort Huachuca, Arizona." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6454.

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Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 19, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. C. Mark Cowell. Includes bibliographical references.
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9

Lô, Mame Diarra Bousso. "Étude paramétrique et analyse conjointe modélisations / mesures pour la définition d'indicateurs d'expositions aux ondes électromagnétiques en environnement urbain." Thesis, Poitiers, 2017. http://www.theses.fr/2017POIT2251/document.

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Avec la multiplication des antennes radios, due à l’augmentation des abonnés et aux nouveaux services et usages, l’exposition aux ondes électromagnétiques est devenue un sujet interpellant toute une catégorie de personnes, notamment les collectivités locales, les opérateurs, les associations, etc. Dans le domaine de l’exposition des populations aux champs électromagnétiques radiofréquences en milieu urbain, la modélisation numérique a pris depuis quelques années de plus en plus d’importance du fait de la montée en puissance des outils de calcul et de la quantité et qualité des données topographiques disponibles. Elle est utilisée conjointement avec plusieurs types de mesures pour l’analyse et la gestion de risques, comme support d’aide à la décision publique, comme méthode réglementaire et plus largement pour la concertation entre public, industriels, collectivités territoriales, associations, etc. Les résultats de ces méthodes ont donc de plus en plus d’importance. Ce manuscrit permet d'améliorer les connaissances sur la quantification de l'exposition due aux antennes relais en associant mesures et simulations et en prenant en considération la notion de variabilité du champ électrique.Une première partie du travail a permis de déterminer les avantages et les limites des méthodes de calcul, et de même pour les mesures, dans le cadre de l'évaluation de l'exposition à l'échelle urbain. Une seconde partie du travail a consisté à caractériser la variabilité spatiale et temporelle de l'exposition réelle, un point essentiel du fait de la grande variabilité du champ électrique et de la difficulté de trouver un indicateur pertinent pour quantifier l'exposition réelle<br>With the increasing number of mobile phone users, new services and mobile applications, the proliferation of radio antennas has raised concerns about human exposure to electromagnetic waves. This is now a challenging topic to many stakeholders such as local authorities, mobile phone operators, citizen and consumer groups, etc. The assessment of human exposure to radiofrequency electromagnetic fields in the urban environment is mainly based on numerical modeling. The improvement of computational tools together with the quantity and quality of available topographic data has strongly promoted this approach. Numerical modeling is now used in combination with several types of measurements to perform risk analysis and management. It is the basis of decision-making tools and local regulations. It is also used during consultations between the public, the industry, local authorities, governments and associations. The results of these methods are therefore increasingly important. This research contributes to gain knowledge about quantifying the human exposure from base stations through the combination of measurements and simulations, while taking into account the concept of variability of the electrical field. A first part of this work establishes the benefits and limitations of computational methods as well as measurements when assessing exposure to electric fields in urban environment. A second part of this work is aimed at characterizing the spatial and temporal variability of the actual exposure, which is a very important requirement because of the high variability of the electrical field and the difficulty of finding a relevant indicator to quantify the real exposure
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Cooper, Rick. "The effects of a nearby biological body on the parameters of a small hand-held radio operating in the H.F. band (3 MHz-30 MHz)." Ohio : Ohio University, 1992. http://www.ohiolink.edu/etd/view.cgi?ohiou1172245676.

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11

Ngai, Hing-on. "A study of radiowave propagation at 900 MHz in the highly urbanised areas /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19667929.

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12

Canning, Paul John. "Wave breaking on fixed impermeable and mobile permeable beaches." Thesis, University of Brighton, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246822.

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13

Bradley, W. Scott. "Propagation modeling for land mobile satellite communications." Thesis, Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/74511.

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Satellite systems are being planned for two-way communication with mobile vehicles using UHF and L-band frequencies. Of special concern in the system design are the characteristics of propagation in suburban and rural areas where fading occurs due to multipath effects and vegetative shadowing. A review of the literature was performed to study these propagation impairments. Available experimental data are examined, compared, and summarized. Propagation through vegetation is studied in order to compare reported modeling efforts and to determine the parameter dependences of path loss. A simple deterministic path model is then presented to estimate vegetative path loss. An overall statistical model is also proposed to describe the signal level fading statistics. The statistical model is compared to data, and the deterministic path model is used to determine the mean of signal level distribution functions in the presence of shadowing.<br>Master of Science
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Jones, Warren Richard. "Investigation of Mach-Zehnder modulators in the context of fibre supported mm-wave communications." Thesis, Bangor University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261414.

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Chen, Lixia. "Millimeter-Wave Wide Band Antenna Array for 5G Mobile Applications." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39446.

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The thesis presents a compact, miniature, and low cost antenna array designed for millimeter-wave frequencies for future 5th generation (5G) mobile applications. The proposed antenna array is a geometrically modified structure of the Franklin array, which allowed to transform a conventional narrowband array into a wideband antenna array. It is composed of five millimetre-wave circular patch radiation elements with phasing stubs. The designed array, fabricated on the commercial Rogers RO3003 substrate with small form factor of 8x25x0.5 mm3, covers the upcoming 5G band of 23.6-30.3 GHz, with peak gain as 10.8 dB, and high radiation efficiency over the whole operating band. In addition, with frequency sweeping, the proposed antenna array radiation pattern is directive and offers beam steering at the desired angles, acting similarly as a leaky-wave antenna.
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Tharek, A. R. "Propagation and bit error rate measurements in the millimetre wave band about 60GHz." Thesis, University of Bristol, 1988. http://hdl.handle.net/1983/1b39cd0b-e371-46a5-9ce4-463e2167a6b5.

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Atefi, A. "An investigation of radio wave propagation in mobile radio frequency bands." Thesis, University of Liverpool, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354537.

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Simon, Reza Simon Reza. "Diffraction modelling of mobile radio wave propagation in built-up areas." Thesis, Brunel University, 1991. http://bura.brunel.ac.uk/handle/2438/5411.

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This thesis examines theoretical methods of modelling radio wave propagation in built-up areas, with particular application to mobile radio systems Theoretical approaches allow precise quantitative description of the environment in terms of parameters such as mean building heights and densities, in contrast to the ambiguous nature of more conventional empirical models. The models are constructed using both scalar and vector field analysis techniques. The vector analysis is accomplished using the Geometrical Theory of Diffraction to describe the detailed effects of building shape and positioning, particularly for short-range situations. Over longer ranges propagation can often be described in terms of multiple edge diffraction over building rooftops using a scalar field representation. This mechanism accounts well for measured field strength variations, but is time consuming to calculate accurately using standard methods. A rapid algorithm for calculating scalar diffraction over multiple building edges with arbitrary positioning is constructed. This model can be used for deterministic prediction of sector median field strengths including slow fading variations when appropriate building data exists. It is also applicable to terrain diffraction problems. For the case when only average building parameters are available a closed form solution to the problem of multiple diffraction over buildings of equal heights and spacings is derived. The solution is applicable to any antenna heights and so provides a rapid and efficient way to predict gross propagation characteristics. Both models are tested against measurements made in the UHF band and are found to yield good prediction accuracy.
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Mousselon, Laure. "Radio Wave Propagation Measurements and Modeling for Land Mobile Satellite Systems." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/10155.

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The performance of a mobile satellite communications link is conditioned by the characteristics of the propagation path between a satellite and mobile users. The most important propagation effect in land mobile satellite system is roadside attenuation of the signals due to vegetation or urban structures. System designers should have the most reliable information about the statistics of the propagation channel to build reliable systems that can compensate for bad propagation conditions. In 1998, the Virginia Tech Antenna Group developed a simulator, PROSIM, to simulate a propagation channel in the case of roadside tree attenuation in land mobile satellite systems. This thesis describes some improvements to PROSIM, and the adaptation and validation of PROSIM for Digital Audio Radio Satellite systems operating at S-band frequencies. The performance of the simulator for S-band frequencies was evaluated through a measurement campaign conducted with the XM Radio signals at 2.33 GHz in various propagation environments. Finally, additional results on dual satellite systems and fade correlation are described.<br>Master of Science
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Elshaer, Ehab. "Millimetre-Wave Spectrum Sharing in Future Mobile Networks : Techno-Economic Analysis." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-206078.

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Mobile operators passed through many phases in the market over the last several years, since the beginning of mobile broadband services. When the first smart phone was introduced in 2007, it caused a huge increase in the traffic and the users demand kept on increasing. This exponential growth has led to a severe shortage in the available capacity which caused that mobile users don’t have their promised quality of service and coverage. Operators began to put different scenarios for the next-generation mobile networks, putting in consideration the expected increase in the number of users along with their high demand.As a new proposed solution to the scarcity of empty spectrum slots, operating in higher frequency bands (noted as mmwave) emerged as a solution that will provide larger bandwidths with lower prices for the license. Mmwave will provide users with high data rates but on the other hand, has a low penetration rate that can be fixed by increasing the base stations. Another technique for the operators to follow is that they share their own spectrum with each other, by changing the classic way of exploiting the spectrum which proved a low efficiency and high cost, operators can increase their spectrum and coverage with lower cost.To get a clear understanding of how the operators will decide their future strategies, a technical analysis of the new strategies will not be enough, a technical one also will make it clearer and will help the operators in making the decision. The objective of this thesis is to perform a Techno-Economic analysis to get a full image of the system performance. Our system will consist of 2 operators working in mmwave band with antennas equipped with directional beamforming and the base station transmitters will consist of small cells serving outdoor users only. The main question we want to answer is what will be the effect of decreasing the beamwidth on the system performance and when the operators will need to share their spectrum with each other. The performance evaluation will be based on measuring the downlink achievable rate. As we will be performing an economical evaluation, the number of base stations required in each strategy will be an important parameter to evaluate its economic feasibility and cost savings. The different scenarios will include variations of the beamwidth and coordination between the operators with an objective of seeking the best performance along with cost savings. The results should give us a clear look on how the operators will decide for a certain strategy depending on downlink data rate as a KPI and the number of deployed base stations as a limiting factor.
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Secomb, Dorothy Margaret School of Social Science &amp Policy UNSW. "Retirement in Mobile and Manufactured Housing on the North Coast of New South Wales, Australia." Awarded by:University of New South Wales. School of Social Science and Policy, 2000. http://handle.unsw.edu.au/1959.4/17488.

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This study considers relocatable homes as an alternative housing choice for male and female retirees fifty years of age and over. Homogeneous parks and estates planned for a specific type of relocatable home are compared with those which evolved from tourist parks and retain sites for both permanent and short-term occupancy. Four relocatable home environments are considered: caravan parks, mobile homes in mixed parks, manufactured homes in mixed parks and manufactured housing estates. The differential effects of 'age', 'house type' and 'housing environment' upon 'residential satisfaction', 'sense of community within the neighbourhood', 'social integration in the community' and 'psychological adjustment' form the analytical framework of the study. Residents of 34 parks/ estates on the North Coast of New South Wales completed 778 questionnaires. Case studies, interviews, letters and written comments provided data for qualitative analysis. Approximately 94% of respondents are satisfied with their homes and housing environments. Residential satisfaction is most influenced by the interactions and perceptions of residents; psychological adjustment is influenced by a positive attitudes towards self and one's neighbours; integration in the community is affected by levels of network. Each of these relate strongly with having a sense of community in the neighbourhood. Space internal to the dwelling relates to satisfaction, adjustment and community integration. External space relates to the need for a well planned neighbourhood which affords privacy, safety and amenities. The need for meeting places for small and large groups was recurrent. The results suggest that residents of relocatable homes tend to retain affiliation with organisations joined prior to relocation. They are not reliant on their new neighbours to integrate in their community. This result is contrary to prior research which studied site built homes and traditional neighbourhoods. The present high levels of residential satisfaction would rise if it were not for the overwhelming uncertainty of tenure and unjustifiable rises in site rent. The study reviews government policy especially in relation to tenure. A relocatable home offers no more affordability than a site-built home in the same area in the long-term but it does offer a preferred retirement lifestyle.
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Barts, Robert Michael. "Statistical modeling and simulation of mobile satellite propagation." Thesis, Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/80107.

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Land mobile satellite systems that are currently being designed for implementation in the next decade will need to operate in the presence of propagation effects such as vegetative shadowing and multipath that will cause signal fading. This paper discusses the statistical modeling and simulation of the land mobile satellite fading environment. Simple models are developed to approximate the complex analytical expressions for the fade distributions. The Average Path Model, which relates the physical parameters of the vegetation along the path to the propagation model parameters, is verified and shown as a useful model for estimating the propagation parameters. Discrepancies between the VT Propagation Simulator and the analytical models are resolved and results comparing secondary fading statistics from the simulator to measured data are given. Results of a study using the propagation simulator to simulate spatial diversity to combat vegetative fading are given.<br>Master of Science
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23

Jafari, Seyedfaraz. "Near-field millimeter-wave radio-frequency exposure analysis." Electronic Thesis or Diss., Institut polytechnique de Paris, 2023. http://www.theses.fr/2023IPPAT034.

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Cette thèse vise à déterminer la densité de puissance absorbée (APD) en tenant compte du couplage et des réflexions multiples entre l'antenne et le corps humain, ce qui pose des défis dans l'évaluation de l'APD en raison de leur proximité étroite.La première partie de la thèse explore le concept de mesure de l'APD à l'intérieur d'un fantôme de tissu cutané, en se concentrant spécifiquement sur son application dans les technologies 5G. Cependant, la mesure de l'APD à l'intérieur du fantôme de tissu cutanéest limitée en raison de la faible profondeur de pénétration des champs aux ondes millimétriques et quasi-millimétriques. Pour surmonter cette limitation, une technique de reconstruction est utilisée, en utilisant la méthode du spectre de plane inverse. Le champélectrique est échantillonné à une distance spécifique à l'intérieur du fantôme, permettant de déterminer la densité de puissance absorbée à la surface de la peau humaine. Dans la deuxième partie, une approche non invasive basée sur la fonction de Green dyadique (DGF) est proposée pour l'évaluation de l'APD. Cette méthode tient compte du couplage entre le modèle de peau humaineet le dispositif en cours de test (DUT). L'espace entier est divisé en deux demi-espaces : la demi-espace supérieur est rempli d'air, où l'antenne est positionnée, et le demi-espace inférieur est rempli d'un équivalent de peau humaine. L'équation intégrale de champ électrique (EFIE), basée sur les DGF spatiaux, est résolue à l'aide de la méthode des moments (MoM) pour reconstruire les courants équivalents. L'APD est évaluée en fonction des courants équivalents reconstruits sous l'interface air-fantôme.En plus des techniques proposées, la thèse examine les exigences de mesure pour les deux approches, y comprisl'incertitude de mesure du champ électrique, la résolution angulaire d'échantillonnage et la taille requise du fantôme.Les résultats démontrent que les techniques proposées présentent une nouvelle méthodologie pour évaluerl'APD, en tenant compte du couplage entre le corps humain et l'antenne, notamment dans le contexte de l'exposition aux appareils portables fonctionnant au dessus de 6 GHz.Pour garantir la sécurité des individus exposés au RF-EMF à des fréquences supérieures à 6 GHz, le taux d'absorption spécifique (SAR) est remplacé par la densité de puissance (PD) en tant que critère d'exposition, comprenant la densité de puissance absorbée (APD) et la densité de puissance incidente (IPD). L'IPD mesure la densité de puissance du rayonnement émis par une antenne dans l'espace libre, mais il peut ne pas être adapté aux situations d'exposition en champ proche où l'antenne est près du corps humain. Les interactions entre le corps humain et l'antenne, telles que le couplage et les réflexions multiples, peuvent entraîner des changements dans les schémas de rayonnement et les niveaux d'exposition, rendant l'IPD inadéquat. En revanche, l'APD prend en compte le couplage entre l'antenne et le corps humain, permettant une évaluation plus précise du niveau d'exposition réel.Cette thèse vise à déterminer l'APD aux fréquences millimétriques 5G en tenant compte du couplage entre l'antenne et le corps humain lorsqu'ils sont en proximité. Deux approches sont proposées :Évaluation de l'APD dans un Modèle de Peau Humaine : Cette approche implique l'utilisation d'une antenne patch 2x2 fonctionnant à 10, 24 et 60 GHz avec une puissance rayonnée de 200 milliwatts. Le champ E est échantillonné à l'intérieur d'un modèle de tissu cutané humain à différentes distances de la surface de la peau. Le champ E sous l'interface air-fantôme est ensuite évalué par rétropropagation à l'aide de la méthode d'expansion d'onde plane (PWS). Les résultats montrent une erreur de reconstruction inférieure à 9,4 %, 7,35 % et 7,8 % respectivement à 10, 24 et 60 GHz, pour des distances supérieures à 1 mm entre l'antenne et le fantôme<br>This thesis aims to determine the absorbed power density (APD) considering the coupling and multiple reflections between the antenna and the human body, which poses challenges in assessing APD due to their close proximity.The first part of the thesis explores the concept of measuring APD inside a skin tissue phantom, specifically focusing on its application in 5G technologies.However, measuring APD inside the skin tissue phantom is limited due to the shallow penetration depth of fields at millimeter and quasi-millimeter waves. To overcome this limitation, a reconstruction technique is employed, utilizing the backward plane-wave spectrum(PWS) method. The electric field is sampled at a specific distance within the phantom, enabling the determination of APD at the human skin surface.In the second part, a non-invasive approach based on the dyadic Green's function (DGF) is proposed for APD assessment. This method takes into account the coupling between the human skin model and the device under test (DUT). The entire space is dividedinto two half-spaces : the upper half-space (z &gt; 0) is filled with air, where the antenna is positioned, and the lower half-space is filled with an equivalent human skin liquid or solid. The electric field integral equation (EFIE), based on spatial DGFs, is solved using the method of moments (MoM) to reconstruct the equivalent currents. The electric field is sampled on the surface of a hemisphere surrounding the antenna, and the APD is evaluated based on the reconstructed equivalent currents beneath the air-phantom interface.In addition to the proposed techniques, the thesis investigates the measurement requirements for both approaches, including E-field measurement uncertainty, sampling angular resolution, and the required size of the phantom.The findings demonstrate that the proposed techniques present a novel methodology for assessing APD, taking into consideration the coupling between the human body and the antenna, particularly in the context of exposure to handheld devices operating above 6GHz
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24

Östlin, Erik. "On Radio Wave Propagation Measurements and Modelling for Cellular Mobile Radio Networks." Doctoral thesis, Karlskrona : Blekinge Institute of Technology, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00443.

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To support the continuously increasing number of mobile telephone users around the world, mobile communication systems have become more advanced and sophisticated in their designs. As a result of the great success with the second generation mobile radio networks, deployment of the third and development of fourth generations, the demand for higher data rates to support available services, such as internet connection, video telephony and personal navigation systems, is ever growing. To be able to meet the requirements regarding bandwidth and number of users, enhancements of existing systems and introductions of conceptually new technologies and techniques have been researched and developed. Although new proposed technologies in theory provide increased network capacity, the backbone of a successful roll-out of a mobile telephone system is inevitably the planning of the network’s cellular structure. Hence, the fundamental aspect to a reliable cellular planning is the knowledge about the physical radio channel for wide sets of different propagation scenarios. Therefore, to study radio wave propagation in typical Australian environments, the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the Australian Telecommunications Cooperative Research Centre (ATcrc) in collaboration developed a cellular code division multiple access (CDMA) pilot scanner. The pilot scanner measurement equipment enables for radio wave propagation measurements in available commercial CDMA mobile radio networks, which in Australia are usually deployed for extensive rural areas. Over time, the collected measurement data has been used to characterise many different types of mobile radio environments and some of the results are presented in this thesis. The thesis is divided into an introduction section and four parts based on peer-reviewed international research publications. The introduction section presents the reader with some relevant background on channel and propagation modelling. Also, the CDMA scanner measurement system that was developed in parallel with the research results founding this thesis is presented. The first part presents work on the evaluation and development of the different revisions of the Recommendation ITU-R P.1546 point-to-area radio wave propagation prediction model. In particular, the modified application of the terrain clearance angle (TCA) and the calculation method of the effective antenna height are scrutinized. In the second part, the correlation between the smallscale fading characteristics, described by the Ricean K-factor, and the vegetation density in the vicinity of the mobile receiving antenna is investigated. The third part presents an artificial neural network (ANN) based technique incorporated to predict path loss in rural macrocell environments. Obtained results, such as prediction accuracy and training time, are presented for different sized ANNs and different training approaches. Finally, the fourth part proposes an extension of the path loss ANN enabling the model to also predict small-scale fading characteristics.
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25

Sajedin, M., Issa T. Elfergani, Jonathan Rodriguez, Raed A. Abd-Alhameed, M. Fernandez-Barciela, and M. Violas. "Ultra-Compact mm-Wave Monolithic IC Doherty Power Amplifier for Mobile Handsets." MDPI, 2021. http://hdl.handle.net/10454/18600.

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Yes<br>This work develops a novel dynamic load modulation Power Amplifier (PA) circuity that can provide an optimum compromise between linearity and efficiency while covering multiple cellular frequency bands. Exploiting monolithic microwave integrated circuits (MMIC) technology, a fully integrated 1W Doherty PA architecture is proposed based on 0.1 µm AlGaAs/InGaAs Depletion- Mode (D-Mode) technology provided by the WIN Semiconductors foundry. The proposed wideband DPA incorporates the harmonic tuning Class-J mode of operation, which aims to engineer the voltage waveform via second harmonic capacitive load termination. Moreover, the applied post-matching technique not only reduces the impedance transformation ratio of the conventional DPA, but also restores its proper load modulation. The simulation results indicate that the monolithic drive load modulation PA at 4 V operation voltage delivers 44% PAE at the maximum output power of 30 dBm at the 1 dB compression point, and 34% power-added efficiency (PAE) at 6 dB power back-off (PBO). A power gain flatness of around 14 ± 0.5 dB was achieved over the frequency band of 23 GHz to 27 GHz. The compact MMIC load modulation technique developed for the 5G mobile handset occupies the die area of 3.2.<br>This research was funded by the European Regional Development Fund (FEDER), through COMPETE 2020, POR ALGARVE 2020, Fundação para a Ciência e a Tecnologia (FCT) under i-Five Project (POCI-01-0145-FEDER-030500). This work is also part of the POSITION-II project funded by the ECSEL joint Undertaking under grant number Ecsel-345 7831132-Postitio-II-2017-IA. This work is supported by FCT/MCTES through national funds and when applicable co-funded EU funds under the project UIDB/50008/2020-UIDP/50008/2020. The authors would like to thank the WIN Semiconductors foundry for providing the MMIC GaAs pHEMT PDKs and technical support. This work is supported by the Project TEC2017-88242-C3-2-R- Spanish Ministerio de Ciencia, Innovación e Universidades and EU-FEDER funding.
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26

Cutler, Steven. "Implementation of a Variable Duty Factor Controller on a Six-Legged Axi-Symmetric Walking Robot." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2887.

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Hexplorer is a six-legged walking robot developed at the University of Waterloo. The robot is controlled by a network of seven digital signal processors, six of which control three motors each, for a total of 18 motors. Brand new custom electronics were designed to house the digital signal processors and associated circuitry. A variable duty factor wave gait, developed by Yoneda et al. was simulated and implemented on the robot. Simulation required an in-depth kinematic analysis that was complicated by the mechanical design of parallel mechanism comprising the legs. These complications were handled in both simulation and implementation. However, due to mechanical issues Hexplorer walked for only one or two steps at a time.
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27

Abdullah, Hazim B. "Microwave and millimetre-wave omnidirectional antennas in the azimuth plane for mobile communications." Thesis, University of Bath, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261831.

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28

IOTTI, LORENZO. "Design of mm-Wave Local Oscillator Building Blocks for Next-Generation Mobile Backhaul." Doctoral thesis, Università degli studi di Pavia, 2017. http://hdl.handle.net/11571/1203365.

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Point-to-point wireless links in the E-Band (71-76GHz and 81-86GHz bands) can provide high-data-rate, easily-deployable, cheap and flexible backhaul solutions, important enablers for the mobile network evolution towards 5G. The development of CMOS/BiCMOS integrated transceivers for E-Band backhaul applications can help reducing the cost and footprint of the equipment, but presents design challenges, mostly related to the use of spectrally-efficient high-order modulations, which mandate high linearity and low phase noise. In this dissertation, local-oscillator generation requirements for E-Band backhaul applications are addressed. Phase-noise specifications for the frequency synthesizer are identified, and custom analog building blocks, namely a VCO and a frequency quadrupler, are proposed. The blocks have been designed in 55nm BiCMOS technology,and measurement results on test chips are presented. A noise-scalable multi-core oscillator is proposed as a key block of the frequency synthesizer. It achieves ultra-low phase noise performance, and allows to trade noise and power consumption according to system requirements, a useful feature in E-Band communications. An analytical model describing the effect of mismatches on the multi-core oscillator is also presented. It provides understanding of the robustness of the proposed solution, and useful insights on in-phase coupled oscillator design. Measurement results demonstrate advances over state of the art, primarily in terms of low phase-noise performance, and show how the proposed circuits are suitable as local oscillator building blocks in direct-conversion E-Band backhaul transceivers.
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29

Akstaller, Wolfgang Paul [Verfasser]. "Electrothermal and Nonlinear Modeling of Surface Acoustic Wave Mobile Radio Filters / Wolfgang Paul Akstaller." München : Verlag Dr. Hut, 2019. http://d-nb.info/1194288782/34.

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30

Kermoal, John Phillipe. "Coherence bandwidth characterisation for indoor mobile radio microcells at microwave and millimetre wave frequencies." Thesis, University of South Wales, 1998. https://pure.southwales.ac.uk/en/studentthesis/coherence-bandwidth-characterisation-for-indoor-mobile-radio-microcells-at-microwave-and-millimetre-wave-frequencies(f01885d8-8010-4a49-a3e3-356e01911a46).html.

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This thesis reports measured and predicted results of the coherence bandwidth of indoor mobile radio microcells at 11 GHz and 62.4 GHz. Furthermore, the influence of the antennas radiation patterns and the effect of furniture on the value of the coherence bandwidth has been investigated. A two branch frequency diversity system has been developed and used to simultaneously record the amplitude variation of the sideband signals. Frequency separations in the range between 5 and 240 MHz have been used at both 11 GHz and 62.4 GHz. In order to assist in explaining experimental results, a ray-tracing algorithm based on the image method, has been developed. It considers reflections up to the third order and assumes smooth walls, all with the same dielectric parameters. The correlation coefficients between signal envelopes separated in frequency are measured and expressed as functions of distance between terminals. The level below which the correlation stays for a given percentage of time has been measured and plotted against frequency spacing to generate the frequency correlation function of the microcell. The coherence bandwidth, corresponding to correlation levels of 0.5, 0.7 and 0.9, are determined from these functions. The coherence bandwidth has also been measured at each position in the microcell and its value for a given percentage of mobile terminal locations is given. The difference between results obtained from both methods are outlined and explained. Results are presented for three corridors and a room. A comparison between experimental results obtained at 11 GHz and 62.4 GHz is also given.
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31

Ghatak, Gourab. "Millimeter wave multi-RAT small cells for heterogeneous mobile services : performance analysis and optimization." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLT010/document.

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Les futures applications sans fil anticipent une explosion de la pléthore de cas d'utilisation et de services, qui ne peut être soutenue par des améliorations incrémentielles des schémas de communication existants. Pour cela, deux axes de recherche sont particulièrement intéressants: la densification du réseau à l'aide de petites cellules et la communication par ondes millimétriques (ondes millimétriques). Dans cette thèse, nous modélisons et évaluons des réseaux cellulaires constitués de petites cellules à ondes millimétriques utilisant la technique d'accès multi-radio (RAT) déployées au-dessus de la macro-architecture existante. Premièrement, nous modélisons mathématiquement un déploiement homogène de petites cellules multi-RAT et caractérisons les performances de l'utilisateur et du réseau en termes de probabilité de couverture signal sur brouillage plus rapport de bruit (SINR), de débit descendant et de probabilité de surcharge de cellule. Ensuite, nous étudions l'association des utilisateurs à différents niveaux et la sélection optimale de différents RAT, de manière à optimiser ces mesures de performance. En règle générale, les modèles de réseau cellulaire qui supposent des déploiements homogènes de petites cellules ne tiennent pas compte des nuances des caractéristiques de blocage urbain. Pour résoudre ce problème, nous modélisons les emplacements de petites cellules le long des routes d'une ville, puis nous prenons en compte les blocages de signaux dus à la construction d'immeubles ou au déplacement de véhicules sur les routes. Sur ce réseau, nous supposons que l’opérateur prend en charge trois types de services v.i.z., les communications ultra-fiables à faible temps de latence (URLLC), les communications massives de type machine (mMTC) et le haut débit mobile amélioré (eMBB) avec des besoins différents. En conséquence, nous étudions la sélection optimale de RAT pour ces services avec divers blocages de véhicules. Enfin, sur la base du modèle de déploiement sur route de petites cellules à ondes millimétriques, nous étudions un réseau conçu pour prendre en charge simultanément des services de positionnement et de données. Nous caractérisons la précision du positionnement en fonction des limites de la localisation, puis étudions des stratégies optimales de partitionnement des ressources et de sélection de la largeur de faisceau afin de répondre à diverses exigences de positionnement et de débit de données<br>Future wireless applications anticipate an explosion in the plethora of use-cases and services, which cannot be sustained by incremental improvements on the existing communication schemes. For this, two research directions are particularly attractive: network densification using small cells and millimeter wave (mm-wave) wave communications. In this thesis, we model and evaluate cellular networks consisting of multi-radio access technique (RAT) mm-wave small cells deployed on top of the legacy macro-architecture. First, we mathematically model a homogeneous deployment of multi-RAT small cells and characterize the user and network performance in terms of signal to interference plus noise ratio (SINR) coverage probability, downlink throughput, and the cell overloading probability. Then, we study users association to different tiers and optimal selection of different RATs, so as to optimize these performance metrics. Generally, cellular network models that assume homogeneous deployments of small cells fail to take into account the nuances of urban blockage characteristics. To address this, we model the small cell locations along the roads of a city, and subsequently, we take into consideration the signal blockages due to buildings or moving vehicles on the roads. In this network, we assume that the operator supports three types of services v.i.z., ultra-reliable low-latency communications (URLLC), massive machine-type communications (mMTC), and enhanced mobile broadband (eMBB) with different requirements. Consequently, we study the optimal RAT selection for these services with varying vehicular blockages. Finally, based on the on-road deployment model of mm-wave small cells, we study a network designed to support positioning and data services simultaneously. We characterize the positioning accuracy based on the localization bounds and then study optimal resource partitioning and beamwidth selection strategies to address varied positioning and data-rate requirements
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32

Ghatak, Gourab. "Millimeter wave multi-RAT small cells for heterogeneous mobile services : performance analysis and optimization." Electronic Thesis or Diss., Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLT010.

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Les futures applications sans fil anticipent une explosion de la pléthore de cas d'utilisation et de services, qui ne peut être soutenue par des améliorations incrémentielles des schémas de communication existants. Pour cela, deux axes de recherche sont particulièrement intéressants: la densification du réseau à l'aide de petites cellules et la communication par ondes millimétriques (ondes millimétriques). Dans cette thèse, nous modélisons et évaluons des réseaux cellulaires constitués de petites cellules à ondes millimétriques utilisant la technique d'accès multi-radio (RAT) déployées au-dessus de la macro-architecture existante. Premièrement, nous modélisons mathématiquement un déploiement homogène de petites cellules multi-RAT et caractérisons les performances de l'utilisateur et du réseau en termes de probabilité de couverture signal sur brouillage plus rapport de bruit (SINR), de débit descendant et de probabilité de surcharge de cellule. Ensuite, nous étudions l'association des utilisateurs à différents niveaux et la sélection optimale de différents RAT, de manière à optimiser ces mesures de performance. En règle générale, les modèles de réseau cellulaire qui supposent des déploiements homogènes de petites cellules ne tiennent pas compte des nuances des caractéristiques de blocage urbain. Pour résoudre ce problème, nous modélisons les emplacements de petites cellules le long des routes d'une ville, puis nous prenons en compte les blocages de signaux dus à la construction d'immeubles ou au déplacement de véhicules sur les routes. Sur ce réseau, nous supposons que l’opérateur prend en charge trois types de services v.i.z., les communications ultra-fiables à faible temps de latence (URLLC), les communications massives de type machine (mMTC) et le haut débit mobile amélioré (eMBB) avec des besoins différents. En conséquence, nous étudions la sélection optimale de RAT pour ces services avec divers blocages de véhicules. Enfin, sur la base du modèle de déploiement sur route de petites cellules à ondes millimétriques, nous étudions un réseau conçu pour prendre en charge simultanément des services de positionnement et de données. Nous caractérisons la précision du positionnement en fonction des limites de la localisation, puis étudions des stratégies optimales de partitionnement des ressources et de sélection de la largeur de faisceau afin de répondre à diverses exigences de positionnement et de débit de données<br>Future wireless applications anticipate an explosion in the plethora of use-cases and services, which cannot be sustained by incremental improvements on the existing communication schemes. For this, two research directions are particularly attractive: network densification using small cells and millimeter wave (mm-wave) wave communications. In this thesis, we model and evaluate cellular networks consisting of multi-radio access technique (RAT) mm-wave small cells deployed on top of the legacy macro-architecture. First, we mathematically model a homogeneous deployment of multi-RAT small cells and characterize the user and network performance in terms of signal to interference plus noise ratio (SINR) coverage probability, downlink throughput, and the cell overloading probability. Then, we study users association to different tiers and optimal selection of different RATs, so as to optimize these performance metrics. Generally, cellular network models that assume homogeneous deployments of small cells fail to take into account the nuances of urban blockage characteristics. To address this, we model the small cell locations along the roads of a city, and subsequently, we take into consideration the signal blockages due to buildings or moving vehicles on the roads. In this network, we assume that the operator supports three types of services v.i.z., ultra-reliable low-latency communications (URLLC), massive machine-type communications (mMTC), and enhanced mobile broadband (eMBB) with different requirements. Consequently, we study the optimal RAT selection for these services with varying vehicular blockages. Finally, based on the on-road deployment model of mm-wave small cells, we study a network designed to support positioning and data services simultaneously. We characterize the positioning accuracy based on the localization bounds and then study optimal resource partitioning and beamwidth selection strategies to address varied positioning and data-rate requirements
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33

Norman, Paul. "European police cooperation : police accountability and the policing of internationally-mobile offending in England and Wales." Thesis, University of Sussex, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.481734.

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34

Ngai, Hing-on, and 魏慶安. "A study of radiowave propagation at 900 MHz in the highly urbanised areas." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31213546.

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35

Jimenez, Blasco Mercedes. "A coupling matrix vision for mobile filtering devices with micro-acoustic wave technologies. A systematic approach." Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/314191.

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Con el espectro radioeléctrico cada vez más saturado, los filtros y duplexores son elementos claves de la tecnología en el mercado de dispositivos discretos para la telefonía móvil. El segmento de usuario de los sistemas de comunicaciones inalámbricas aprovecha las destacadas propiedades de los dispositivos filtrantes basados en resonadores acústicos. Generalmente, el diseño de dispositivos de onda acústica ha sido asumido por técnicas de optimización debido a las restrictivas limitaciones impuestas por la viabilidad tecnológica de los resonadores SAW y BAW, así como las exigentes especificaciones eléctricas. Una respuesta de transmisión muy restrictiva y factores tecnológicos muy limitantes conducen a hacer el diseño más y más complejo y una tarea muy desafiante. El objetivo del trabajo está enfocado en facilitar el diseño de filtros/duplexores y hacerlo más eficiente. En consecuencia, la formulación inicial del problema se ha centrado en la viabilidad tecnológica para implementar filtros de onda acústica. Proporcionar una metodología sistemática es útil para acelerar la curva de aprendizaje de nuevos diseñadores. Los filtros de microondas con elevada selectividad son posibles si sus funciones de transferencia incorporan ceros de transmisión finitos. La introducción de nodos no-resonantes (NRN) da la posibilidad de diseñar filtros con el máximo número de ceros de transmisión finitos sin tener que implementar acoplamientos directos entre la fuente y la carga. Además, las configuraciones en línea con NRN permiten la extracción de los elementos analíticamente. La típica configuración de filtro ladder presenta similitudes características de acuerdo con las redes de prototipo en línea con nodos resonantes y no-resonantes, que son las propiedades de modularidad, para controlar los ceros de transmisión con resonadores independientes, y respuestas completamente canonícas sin acoplamiento fuente-carga directo. Los elementos de la red pasobanda son dados por ecuaciones explícitas en términos de aquellos en los prototipos en línea con NRN que pueden ser sintetizados analíticamente. Como consecuencia, es posible definir una metodología de síntesis directa para obtener los parámetros pasobanda eléctricos de un filtro RF general que está basado en resonadores acústicos. Este trabajo presenta una metodología que proporciona un procedimiento de síntesis sistemático para diseñar filtros y duplexores ladder basados en resonadores de onda micro-acústica. La metodología de diseño utiliza un enfoque nodal basado en NRN y nodos resonantes. La representación de la red mediante una matriz de acoplamiento mixta de nodos resonantes y no resonantes es capaz de gestionar de forma eficiente las restricciones tecnológicas. El procedimiento es eficiente en tiempo, preciso en los resultados y proporciona un profundo entendimiento de las particulares interacciones que se producen entre las restricciones tecnológicas y el funcionamiento del dispositivo. Un completo paquete de software, con un simulador rápido, preciso y de fácil uso, ha sido desarrollado, permitiendo obtener diseños de primera etapa exitosos. Como resultado de la metodología sistemática, hemos desarrollado un método de diseño que combina y sistemáticamente gestiona redes filtrantes compuestas de bloques de polo extraído con bloques de resonadores acoplados, es decir, celdas ladder con secciones CRF. Además, la metodología has sido extendida exitosamente para tener en cuenta el diseño de divisores de potencia con respuesta filtrante por medio de dos topologías diferentes: la configuración ladder y las secciones CRF. La metodología propuesta ofrece una solución que combina el completo cumplimiento de las máscaras de espectro con topologías preparadas para acomodar las restricciones tecnológicas de la tecnología micro-acústica. La metodología ha sido desarrollada orientada nativamente a gestionar la tecnología, como es el ajuste de la limitación en el acoplo electromagnético, y basada en fundamentos de síntesis rigurosos.<br>With a spectrum more and more overcrowded, filters and duplexers are drivers of the technology in the discrete device mobile market. The user segment of wireless communication systems takes profit of the outstanding performance of filtering devices based on acoustic resonators. Usually, the design of acoustic wave devices have been mainly entrusted to optimization techniques because the stringent constraints imposed by the technological feasibility of SAW and BAW resonators and the challenging electrical specifications. A stringent transmission response and very restrictive technological factors lead the design to a more and more complex and challenging task. The aim of the work is focused on easing the filters/duplexers designs and making it more efficient. Consequently, the initial formulation of the problem was focused on the technological feasibility of acoustic wave filters. Providing a systematic methodology is useful to accelerate the learning curve of new entrant designers. Microwave filters with high selectivity are possible if their transfer functions incorporates finite transmission zeros. The inclusion of non-resonant nodes gives the possibility of designing filters with the maximum number of finite transmission zeros without implementing direct couplings between source and load. Furthermore, inline configuration with NRN allows the extraction of the elements analytically. The common ladder filter configuration exhibits characteristic similarities regarding inline prototype networks with resonant and non-resonant nodes, which are the property of modularity, to control transmission zeros by independent resonators, and fully canonical response without a direct source-load coupling. The elements of the lowpass prototype are given by explicit equations in terms of those in in-line prototypes with non-resonating nodes that can be synthesized analytically. As a consequence it is possible to define a direct synthesis methodology to obtain the bandpass electric parameters of a general RF filter that is based on acoustic resonators. This work presents a methodology that provides a systematic synthesis procedure for designing ladder filters and duplexers based on acoustic wave resonators. The methodology uses a nodal approach based on resonating and non-resonating nodes. The coupling matrix representation with a mix of different nature nodes, resonant and non-resonant, is able to efficiently manage the technological restrictions. The procedure is time efficient, precise in the outcomes and provides a deep understanding of the particular interactions between technological constraints and device performance. A complete software package with fast, accurate and easy-to-use simulator has been developed, enabling starting point design success. As a result of the systematic methodology, we have developed a design method that combines and systematically manages a filtering network composed of extracted-pole blocks with coupling resonators blocks, so it is ladder cells with CRF sections. Moreover, the methodology has been successfully extended to take into consideration filtering power dividers by means of two different topologies: ladder configuration and CRF sections. The proposed methodology offers a solution that combines a complete spectrum fulfillment with topologies ready to accommodate technological constraints of micro-acoustics technologies. The methodology has been developed natively oriented to manage with the technology, such as accommodating electromechanical coupling constraints, leveraged in rigorous synthesis foundations.
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36

Kokshoorn, Matthew Luke. "Channel Estimation and Beam Training for Millimeter Wave Mobile Networks: Point-to-Point, Multi-User, and Multi-Cell." Thesis, The University of Sydney, 2018. http://hdl.handle.net/2123/18082.

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The global shortage of microwave bandwidth has become a critical issue that may inhibit the growth of mobile networks needing to support content-rich applications. For this reason, the underutilized millimeter wave (mmWave) spectrum has attracted significant attention as a medium to support next-generation mobile. Although this spectrum has an abundance of available bandwidth, mmWave wave frequencies also have propagation characteristics that make digital communication very challenging. Due to the signals atmospheric, reflection, and penetration losses, this spectrum suffers from much greater attenuation compared to microwave signals. To overcome these losses, mmWave systems will need to be equipped with large antenna arrays to enable directionality gains through beamforming. Due to the reduced wavelength of mmWave signals, large arrays can be packed into a small area and are therefore suitable for consumer electronics. However, by simply adopting conventional multiple-input multiple-output (MIMO) electronics with high-rate digital components tied to each antenna, the resulting power drain becomes unpractical for portable devices. To reduce hardware cost, complexity, and power consumption, constrained hardware architectures have been proposed for use in mmWave mobile systems. These consist of a small number of RF chains that are tied to the array of antennas through a network of phase shifters. In these architectures the role of beamforming is split across both the analog and the digital domains, which can make the task of channel estimation difficult and time-consuming. Furthermore, due to heavy signal losses, pilot signals will also need to be beamformed in order to get a clear estimate of the channel. In this thesis, we consider this problem of mmWave channel estimation for a wide range of deployment topologies including; point-to-point, multi-user, and multi-cellular. .
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37

Byres, Ronald David. "The application of floating breakwaters in British Columbia." Thesis, University of British Columbia, 1988. http://hdl.handle.net/2429/28370.

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The nature of British Columbia coastal and inland waterways affords many locations where floating breakwaters are or could be used to protect small-craft harbours from wave action. A field survey of many of the current breakwater sites is undertaken in order to establish qualitative performance criteria of various designs. A two-dimensional numerical model is developed to predict the oscillatory response and wave transmission characteristics for a number of common breakwater designs. Finally, experiments with two configurations of breakwater models were carried out in the Hydraulics Laboratory at the University of British Columbia. The experiments were designed to validate the numerical model and to estimate viscous damping coefficients required in the numerical solution.<br>Applied Science, Faculty of<br>Civil Engineering, Department of<br>Graduate
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38

Pages, Guilhem. "Zones d’écoute personnalisées mobiles par approches adaptatives." Electronic Thesis or Diss., Le Mans, 2024. http://www.theses.fr/2024LEMA1012.

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La thèse aborde la création de sound zones (zones d'écoute personnalisées) mobiles par des approches adaptatives. Les méthodes en usage pour la création de sound zones visent à résoudre conjointement la reproduction sonore dans une zone et la minimisation de l'énergie du signal reproduit dans l'autre zone, à partir d'un réseau de haut-parleurs. La thèse se divise en deux parties : l'estimation des réponses impulsionnelles et les sound zones mobiles. L'objectif de cette thèse est de créer deux zones de l'espace dont le champ acoustique est contrôlé, ces zones pouvant bouger dans l'espace au cours du temps. Dans la première partie, l'estimation des réponses impulsionnelles du système est détaillée, prérequis nécessaire pour les algorithmes de sound zones. A partir des méthodes adaptatives existantes pour l'estimation de systèmes multi-entrées multi-sorties variant dans le temps, une nouvelle méthode appliquée à l'acoustique et MISO est présentée. Cette méthode, appelée MISO-Autostep, permet d'estimer les réponses impulsionnelles au cours du temps sans avoir de paramètres à ajuster finement. Dans la seconde partie, l'algorithme de \sound zones BACC-PM est réécrit sous forme récursive. Cette capacité à mettre à jour les coefficients des filtres au cours du temps ouvre la voie à s'adapter à des changements temporels dans la géométrie du système. Enfin, des résultats préliminaires sont présentés avec l'utilisation conjointe des deux algorithmes adaptatifs dans le cas d'une modification brusque de la géométrie du système<br>The thesis deals with the creation of mobile sound zones using adaptive approaches. The methods in use for the creation of sound zones aim to jointly resolve the sound reproduction in one zone and the minimisation of the energy of the signal reproduced in the other zone, from an array of loudspeakers. The thesis is divided into two parts: the estimation of impulse responses and moving sound zones. The aim of this thesis is to create two zones in space with a controlled sound field, which can move in space over time. In the first part, the estimation of the system's impulse responses is detailed, a necessary prerequisite for sound zone algorithms. Based on existing adaptive methods for estimating time-varying multi-input, multi-output systems, a new method applied to acoustics and MISO is presented. This method, called MISO-Autostep, makes it possible to estimate impulse responses over time without having to fine-tune any parameters. In the second part, the BACC-PM sound zone algorithm is rewritten in recursive form. This ability to update the filter coefficients over time opens up the possibility of adapting to temporal changes in the system geometry. Finally, preliminary results are presented with the joint use of the two adaptive algorithms in the case of an abrupt change in the system geometry
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39

Cox, Gavin J. "Techniques for pattern control of a dielectric rod antenna suitable for use in mobile communications." Thesis, Loughborough University, 2002. https://dspace.lboro.ac.uk/2134/12693.

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This thesis describes the development of antennas suitable for mobile coinmunication systems based on a dielectric rod antenna fed from circular waveguide. Pattern control of the antenna is implemented using a combination of Frequency Selective Surface (FSS) elements and metallic endcaps placed on the antenna Both linear and circular polarised feeds have been made for these antennas to ensure they are suitable for a wide range of applications. The suitability of the dominant and next, higher order, waveguide mode were investigated and conclusions drawn as to their suitability for this type of antenna. The antennas were extensively modelled using a commercial TLM based solver and the results of these simulations were compared to the comprehensive set of antenna pattern measurements and S-parameter measurements obtained for the prototype antennas.
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40

Bertrand, Matthieu. "Guides à ondes lentes intégrés dans le substrat pour les applications en bandes RF et millimétriques." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT068/document.

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Du fait de nombreuses avancées technologiques et scientifiques, l'ensemble du réseau de télécommunications a évolué vers une complexité croissante intégrant désormais des débits très importants. Grâce aux larges bandes passantes offertes par les bandes de fréquences millimétriques, les prochaines générations visent à permettre l'augmentation du nombre de services multimédias et de partage de contenus en haute définition. Cette évolution pose la problématique de concevoir des systèmes sans-fils capables de fonctionner en haute fréquence avec des rendements et coûts acceptables, ainsi qu'un encombrement minimum. Ce travail se situe dans le cadre du développement de circuits passifs, de types filtres, coupleurs et guides d'ondes qui répondent à ces défis. Nous avons développé une technique de miniaturisation pour des dispositifs en technologie imprimée, dans un premier temps dédiée aux fréquences inférieures à 20 GHz. Celle-ci repose sur la notion d'onde lente, définie comme la capacité d’une structure à ralentir la propagation des ondes la traversant. Une analyse théorique ainsi que des méthodes de conception ont été développées, puis validées par des mesures. Dans un second temps, nous avons proposé deux technologies distinctes permettant l'intégration de guides d'ondes performants en bande millimétrique en collaboration avec deux laboratoires partenaires. Une étude théorique, la conception de motifs de test et les résultats de mesure sont présentés. Ces travaux constituent une base pour la réalisation ultérieure en bande millimétrique de topologies miniaturisées grâce aux ondes lentes<br>The last decades have seen the evolution of communication networks towardgreater complexity and efficiency, being now able to carry significant data rates. This evolution is the result of both scientific and technological breakthroughs. Thanks to the wide bandwidths available at millimeter-wave frequencies, the future generations will be able to supply for the the increasing demand in multimedia services, especially high-definition videos. The design of wireless systems which operate at high frequencies with acceptable efficiency, costs, and minimum size thus constitute a decisive challenge. In this context, this work focuses on the development of passive circuits such as filters, couplers and waveguides which address these issues. We developed a miniaturization technique for printed circuits technology, which in a first step is dedicated to frequencies below 20 GHz. This technique is based on a slow-wave concept, defined as the property of any structure which impose lower velocities to the electromagnetic waves. A theoretical analysis, as well as design methods were established and confirmed by measurements. Secondly, we proposed two distinct technological solutions for the integration of efficient waveguides at millimeter-wave frequencies. This work was achieved in collaboration with two other laboratories. A theoretical study, design of test features and measurementswere performed. These results intend to constitute a basis for the future realization of miniaturized slow-wave circuits at millimeter-wave frequency bands
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41

Hariri, Hassan. "Conception et realisation d'un mobile piézoélectrique pour utilisation coopérative." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112321/document.

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L’objectif de cette thèse est de concevoir et de réaliser un mobile piézoélectrique pour utilisation coopérative. Le terme mobile piézoélectrique est utilisé dans cette thèse pour décrire un robot piézoélectrique miniature. Ce robot miniature mobile est actionné par des matériaux piézoélectriques. L’objectif de la thèse est donc la conception et la réalisation d’un robot pouvant être miniaturisé et qui pourrait donc être utilisé dans le cadre du mimétisme des essaims biologiques (fourmis, abeilles…) pour un fonctionnement coopératif.Le robot réalisé est constitué d'un support mince et de patchs piézoélectriques. Les patchs piézoélectriques sont collés sur le support de façon intelligente afin de déplacer le support en milieu terrestre. Dans ce contexte, la thèse est divisée en trois parties.La première partie est consacrée à la modélisation d’un tel système (support mince avec des patches piézoélectriques sur une seule de ses faces). Une modélisation par la méthode des éléments finis est développée pour ce système en se basant sur le principe variationnel d’Hamilton et en considérant l'hypothèse de Love-Kirchhoff. L’originalité de cette modélisation réside dans l’utilisation de la notion du plan neutre pour modéliser ce système asymétrique. Cela permet de ne modéliser le système étudié que par un modèle éléments finis à deux dimensions (2D) tout en tenant compte de la troisième dimension dans le calcul. La deuxième partie présente le principe de fonctionnement du robot qui est inspiré des moteurs linéaire ultrasoniques à ondes progressive. Cette partie présente toutes les étapes de la conception optimale afin de créer les mouvements nécessaires. La conception optimale est étudiée en utilisant la modélisation par éléments finis obtenue dans la première partie. La troisième partie de cette thèse est dédiée à la réalisation d’un prototype expérimental. Le processus de fabrication ainsi que l’électronique associée au robot sont présentés dans cette partie. Le robot est caractérisé expérimentalement en mesurant la vitesse en fonction de la tension appliquée, la vitesse en fonction de masses embarquées par le robot et la vitesse en fonction de la force fournie par le robot. Ce robot est, par ailleurs, comparé avec d’autres systèmes de même nature<br>The objective of this thesis is to design and realize a piezoelectric mobile for cooperative use. The term piezoelectric mobile is used in this thesis to describe a piezoelectric miniature robot. This mobile miniature robot is actuated by piezoelectric materials. The aim of the thesis is the design and the realization of a robot that can be miniaturized and could therefore be used in the context of biological mimicry swarms (ants, bees ...) for a cooperative operation.The realized robot consists of a thin support and piezoelectric patches. Piezoelectric patches are bonded on the support on an intelligent manner in order to move the support on land. In this context, the thesis is divided into three parts.The first part is devoted to the modeling of such a system (thin support with piezoelectric patches on one of its faces). Modeling by the finite element method is developed for this system based on the variational principle of Hamilton and considering the Love-Kirchhoff hypothesis. The originality of this model lies in the use of the concept of the neutral plane to model this asymmetric system. This allows modeling the system studied by a finite element model in two dimensions (2D), taking into account the third dimension in the calculation.The second part presents the operating principle of the robot which is inspired by the linear traveling wave ultrasonic motors. This section presents all the stages of the optimal design to create the necessary movements. The optimal design is investigated using finite element modeling obtained in the first part.The third part of this thesis is devoted to the realization of an experimental prototype. The manufacturing process and the associated electronics for the robot are presented in this section. The robot is characterized experimentally by measuring the speed according to the applied voltage, the speed versus mass loaded by the robot and the speed according to the force provided by the robot. This robot is also compared with other similar systems
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42

Kyllonen, Jaakko. "Design of frequency agile filter and mmWave antenna for 5G mobile devices." Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0117.

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Depuis une vingtaine d’années les communications mobiles sont en constante évolution pour répondre à la demande et aux besoins des utilisateurs notamment en termes de quantité de données à échanger. Le grand public tout comme les professionnels demandent donc des connexions très haut débit fiables avec des temps de latence réduits. L’introduction de la 5G permettra de dépasser les limites actuelles et offrira de nouveaux services mais implique une rupture technologique importante. Dans ce cadre, l’industrie électronique s’intéresse au développement des composants clés de demain permettant de répondre aux différentes évolutions à venir. L’objectif de ce travail de thèse a donc été de trouver des solutions originales pour améliorer les performances des front-end RF des futurs terminaux mobiles. Ainsi deux dispositifs ont été étudiés. Un filtre reconfigurable pour les fréquences inférieures à 6 GHz en technologie LTCC intégrant un switch SP4T en technologie SOI et un réseau d’antennes à faible coût autour de 28 GHz pour la 5G NR (Nouvelle Radio) ont été conçus, réalisés et testés<br>Mobile communications are in constant race to meet the demands of the users, especially in the terms of the amount of data they want to use. The introduction of the 5G NR (New Radio) will exceed the current limits but it needs technological breakthroughs to achieve its goals. To achieve the promises of the new 5G NR communication standard the electronics industry is interested in to develop new key components for tomorrow. The objective of this thesis work has been to design two key components to respond to the different future developments of the mobile devices. Therefore a frequency agile filter for frequencies below 6 GHz and a low cost antenna array around 28 GHz for 5G NR have been designed, manufactured and tested
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43

Bocquet, Constance. "Résolution numérique des équations de l'acoustique dans un domaine contenant des frontières mobiles." Electronic Thesis or Diss., Le Mans, 2024. http://www.theses.fr/2024LEMA1016.

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Les problèmes acoustiques réels mettent souvent en jeu des interactions entre des objets de formes complexes en mouvement à l'interface avec un domaine fluide. Ces travaux de thèse portent sur la modélisation numérique en différences finies de champs acoustiques dans un domaine contenant une frontière mobile.La plupart des études reportées dans la littérature ont été menées à des ordres peu élevés (1 ou 2), donc ce travail porte sur des ordres de convergence élevés pour minimiser l'erreur sur le nombre d'onde acoustique. Le premier axe de recherche est la résolution des équations d'Euler linéarisées, avec une frontière mobile imperméable, modélisée d'une part en condition directe et d'autre part en utilisant la méthode des caractéristiques. Le second axe est l'adaptation de la méthode des caractéristiques pour les frontières mobiles, aux équations d'Euler générales. Le troisième axe se compose des frontières perméables mobiles grâce à un modèle d'impédance dans le domaine temporel. Et enfin, le quatrième axe est la résolution bidimensionnelle sur un modèle simplifié de frontière mobile<br>Realistic acoustic problems often involve interactions between arbitrary-shaped moving objects at the interface with a fluid domain. This thesis focuses on finite-difference numerical modeling of the acoustic field in a domain containing a moving boundary. Most of the studies reported in the literature have been conducted with low-order schemes, so this work focuses on high-order methods to minimize the numerical error on the acoustic wave number. The first research focus is the resolution of the linearized Euler equations, with an impermeable moving boundary, modeled on the one hand by direct conditions and on the other hand using the method of characteristics. The second focus is the extension of the method of characteristics for moving boundaries to the general Euler equations. The third focus consists of moving permeable boundaries using a time-domain impedance model. And finally, the fourth focus is the two-dimensional resolution of a simplified moving boundary model
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44

Ly, Kien Hoa. "Use of a Smartphone Application in the Treatment of Depression : The New Wave of Digital Tools in Psychological Treatment." Doctoral thesis, Linköpings universitet, Psykologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-113996.

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Internet-delivered programs based on cognitive behavior therapy (CBT) have during the past decade shown to work in an effective way for the treatment of depression. Due to its accessibility and independence of time and location, smartphone-based CBT might represent the next generation of digital interventions. Depression is an affective disorder that affects as many as 350 million people worldwide. However, with CBT, depression can be treated, but access to this treatment is scarce due to limited health care resources and trained therapists. As a result of this, health care could highly benefit from the use of smartphones for delivering cost-effective treatment that can be made available to a large part of the population who suffer from depression. One treatment that should be especially suitable for the smartphone format is behavioral activation (BA), since it has strong empirical support as well as the benefits of being flexible and rather simple. The overall aim of the thesis was to test and further develop a BA smartphone application, as well as to build a method for how this smartphone application could be used in a comprehensive and effective way in depression treatment. To fulfill this aim, four studies were conducted. The results showed that smartphones have the ability to be used in an effective way in the treatment of depression, including as an add-on to traditional face-to-face sessions. The results also showed that the smartphone format was experienced as a portable and flexible way of accessing the treatment – and thus could be more present in everyday life. In conclusion, there is reason to believe that smartphones will be integrated even further in society and therefore may serve an important role in future mental health care. Since the first indications reveal that depression can be treated by means of a supported smartphone application, it is highly possible that applications for other mental health problems will follow. Furthermore, in this thesis, the same smartphone application has been tested in three different ways and there is potential to apply smartphones in a range of other formats, such as in relapse prevention and as a way to intensify treatment during periods when needed. From a psychiatric research point of view, as my research group has been doing trials on guided internet treatment for more than 15 years, it is now time to move to the next generation of information technology – smartphones.<br>Internetbaserad kognitiv beteendeterapi (KBT) har under det senaste decenniet visat sig fungera effektivt i behandling av depression. På grund av dess tillgänglighet och flexibilitet i tid och plats har smartphonebaserad KBT potential att bli nästa generation av digitala behandlingar. Depression är en affektiv sjukdom som drabbar så många som 350 miljoner människor världen över. Med hjälp av KBT kan depression behandlas. Dock är tillgången till denna behandling knapp på grund av begränsade resurser i form av utbildade terapeuter. Därmed skulle sjukvården kunna dra stor nytta av användningen av smartphones för att leverera kostnadseffektiv behandling, som kan göras tillgänglig för människor som lider av depression. En behandling som kan vara särskilt lämplig för smartphone-formatet är beteendeaktivering (BA), eftersom den har starkt empiriskt stöd samtidigt som den är flexibel och relativt enkel. Det övergripande syftet med avhandlingen var att testa och vidareutveckla en smartphone-applikation baserad på BA, samt att bygga en behandlingsmetod för denna smartphone-applikation som skulle kunna användas för att effektivt behandla depression. För att uppnå detta syfte genomfördes fyra studier. Resultaten visade att smartphones kan användas på ett effektivt sätt i behandling av depression, bland annat som komplement till traditionella live-sessioner. Resultaten visade också initiala indikationer på att smartphoneformatet upplevdes som ett portabelt och flexibelt sätt att komma åt behandlingen - och därmed blev mer närvarande i vardagen.
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45

Kamanzi, Janvier. "Development of a low energy cooling technology for a mobile satellite ground station." Thesis, Cape Peninsula University of Technology, 2013. http://hdl.handle.net/20.500.11838/1072.

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Thesis submitted in fulfillment of the requirements for the degree Master of Technology:Electrical Engineering in the Faculty ofEngineering at the Cape Peninsula University of Technology Supervisor:Prof MTE KAHN Bellville December 2013<br>The work presented in this thesis consists of the simulation of a cooling plant for a future mobile satellite ground station in order to minimize the effects of the thermal noise and to maintain comfort temperatures onboard the same station. Thermal problems encountered in mobile satellite ground stations are a source of poor quality signals and also of the premature destruction of the front end microwave amplifiers. In addition, they cause extreme discomfort to the mission operators aboard the mobile station especially in hot seasons. The main concerns of effective satellite system are the quality of the received signal and the lifespan of the front end low noise amplifier (LNA). Although the quality of the signal is affected by different sources of noise observed at various stages of a telecommunication system, thermal noise resulting from thermal agitation of electrons generated within the LNA is the predominant type. This thermal noise is the one that affects the sensitivity of the LNA and can lead to its destruction. Research indicated that this thermal noise can be minimized by using a suitable cooling system. A moveable truck was proposed as the equipment vehicle for a mobile ground station. In the process of the cooling system development, a detailed quantitative study on the effects of thermal noise on the LNA was conducted. To cool the LNA and the truck, a 2 kW solar electric vapor compression system was found the best for its compliance to the IEA standards: clean, human and environment friendly. The principal difficulty in the development of the cooling system was to design a photovoltaic topology that would ensure the solar panels were always exposed to the sun, regardless the situation of the truck. Simulation result suggested that a 3.3 kW three sided pyramid photovoltaic topology would be the most effective to supply the power to the cooling system. A battery system rated 48 V, 41.6 Ah was suggested to be charged by the PV system and then supply the power to the vapor compression system. The project was a success as the objective of this project has been met and the research questions were answered.
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46

Chang, Yin-Jung. "Optical Interconnects for In-Plane High-Speed Signal Distribution at 10 Gb/s: Analysis and Demonstration." Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-11182006-155605/.

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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2007.<br>Gee-Kung Chang, Committee Chair ; Thomas K. Gaylord, Committee Co-Chair ; Glenn S. Smith, Committee Member ; John A. Buck, Committee Member ; Ali Adibi, Committee Member ; C. P. Wong, Committee Member.
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47

Biamino, Laurent. "Etude expérimentale de l'interaction d'une onde de choc avec une structure mobile autour d'un axe." Thesis, Aix-Marseille 1, 2011. http://www.theses.fr/2011AIX10093/document.

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Ce travail de thèse s’appuie sur une étude expérimentale en tube à choc, plus précisément, c’est une approche expérimentale de l'étude de l'interaction fluide-structure. Considérons un solide indéformable auquel on laisse un degré de liberté en rotation autour d'un axe. Cette structure ferme un espace clos. Si le contenu de l'espace clos subit le passage d'une onde de choc, ce solide va être mis mouvement et tourner autour de son axe. Concrètement, l'onde de choc va augmenter les caractéristiques physiques, en particulier sa pression, du fluide en contact avec la face impactée de cette porte. La face opposée de la porte ne subissant pas ou que très peu l'influence de l'onde de choc, une seule de ses faces est soumise à la surpression. Au moment de l'impact, le déséquilibre ainsi créé impose une action mécanique sur la porte qui va la faire accélérer et tourner autour de son axe de rotation. Jusqu'à ce stade tout est relativement simple. La difficulté intervient à l'instant où la porte commence à s'ouvrir, car les frontières du volume dans lequel le fluide évolue sont modifiées. Des fuites apparaissent et le gaz qui était maintenu dans un volume clos peut maintenant s'écouler vers un milieu libre. Une communication entre les gaz agissant de chaque coté de la porte est créée modifiant leurs propriétés et par conséquent la pression agissant sur chaque côté de la porte. Les actions mécaniques qui s'appliquent sur la porte ne sont plus les mêmes, et par conséquent l'accélération que la porte subit aussi. Au fur et à mesure que la porte change de position, le problème fluide continue d'être modifié et change en retour son action sur la porte. Cette interaction perdure soit jusqu'à ce que les limites du problème cessent d'être modifiées, la porte ne peut plus bouger, ou bien lorsque les actions mécaniques agissant sur la porte s'équilibrent, les fluides de chaque côté de la porte étant dans le même état physique. Le travail présenté ici est une étude des paramètres du fluide ou du solide en mouvement qui sont les acteurs de la loi comportementale gérant ce système complexe. Pour ce faire, nous avons réalisé une maquette expérimentale mettant en action la physique que nous venons de décrire et nous l'avons adaptée à un tube à choc. En éprouvant de nombreuses configurations expérimentales, nous avons pu déterminer comment l'écoulement interne d'un tube à choc évolue lorsqu'il est plus ou moins ouvert à son extrémité. Comment une porte fermée réagit-elle à l'impact d'une onde de choc et quelles en sont les conséquences sur l'évolution des fluides mis en jeu? Quelles sont les conséquences d'une position différente de la porte au moment de l'impact avec l'onde de choc? Ou encore, quel rôle joue l'intensité de l'onde de choc incidente ou l'inertie de la porte sur toute cette dynamique?<br>This thesis is based on an experimental study carried out in shock tube; in particular, this is an experimental approach to the study of fluid-structure interaction. Consider a rigid body which is allowed to rotate only around an axis and which closes a confined space. If a shock wave crosses the content of the confined space, the body will accelerate and rotate around its axis. Specifically, the shock wave will increase the physical characteristics, especially its pressure, of the fluid acting on the impacted face of the door. The opposite side of the door is not influenced by the incident shock wave, only one of its faces is subjected to overpressure. Following the first impact, the resulting imbalance imposes a mechanical action on the door that will increase its speed and make it turn around its rotation axis. The difficulty comes when the door begins to open: the volume boundaries in which the fluid is contained are modified. Leaks occur and the gas kept in this closed volume can now flow to the atmosphere. Communication between the gas acting on each side of the door is created modifying their properties and consequently the pressure acting on each side of the door.The mechanical actions that apply to the door are no more the same with time, and therefore the acceleration of the door is changing. As the door moves, the fluid problem continues to be changed and in turn it changes its action on the door. This interaction process continues until either the limits of the problem ceases to be changed, the door cannot move, or when the mechanical actions acting on the door are in equilibrium, fluids on each side of the door are in the same physical state. The presented work is a study of the parameters of the fluid or the solid motion which are main actors in the behavioral law managing this complex system. In this aim, we designed an experimental device involving the physics that we have described and we have adapted it to a shock tube. Testing many experimental configurations, we could determine how the internal flow of a shock tube evolves when the end of this shock tube is more or less open.How a closed door reacts to the impact of a shock wave and what are the implications for the evolution of the involved fluids? What are the consequences of a different position of the door at the instant of the impact with the incident shock wave? What role plays the intensity of the incident shock wave or the inertia of the door on this dynamic?
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48

Bera, Manabendra Nath. "Zeeman Deceleration of Supersonic Beam trapping of Paramagnetic Atoms in a Traveling Magnetic Wave." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00599318.

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Le développement de différentes techniques pour contrôler les degrés de liberté internes et externes des molécules et pour produire (ultra-) froide, piège des moléculaire ensembles ouvrir des voies différentes à la physique et la chimie dans le régime de basse température. Il s'agit notamment de nombreux territoires en physique comme, phases quantiques de la matière, traitement de l'information quantique, les froides collisions moléculaires, les chimies froides et aussi de divers tests de haute précision pour la physique fondamentale. Cette thèse décrit diverses expériences de guidage et de décélération des faisceaux supersoniques d'atomes paramagnétiques à l'aide de champs magnétique inhomogène dépendent du temps. Ces champs magnétiques inhomogènes ont été utilisés pour exercer une force sur les atomes ou les molécules paramagnétiques, qui résultent de l'effet Zeeman. Le principe du ralentisseur Zeeman nouvellement développé est de produire un déplacement tridimensionnel du piège magnétique, à la vitesse initiale du faisceau. Le contrôle de la dépendance temporelle du champ magnétique nous permet de contrôler la vitesse du piège magnétique co-mobile, procurant ainsi une décélération d'une classe de vitesse du faisceau supersonique. Le piège magnétique co- mobile est déduit à partir d'une onde magnétique mobile, offrant un minimum de distorsion du piège lors de sa propagation. Les propriétés transverses du piège sont réglables grâce à un champ magnétique transversal quadrupolaire, qui peut être ajusté indépendamment des propriétés de vitesses et l'accélération du piège. Une grande part du travail de thèse a été consacrée à la conception, la réalisation et la construction du montage expérimental, consistant en un jet supersonique et en un dispositif complexe de bobines pour réaliser l'onde magnétique progressive, formant un piège magnétique mobile. Le jet froid pulsé d'atomes métastables est produit par expansion supersonique à travers une valve refroidie à l'azote liquide, excités dans l'état métastable par une décharge électrique. Nous avons guidé le jet d'argon au travers d'un tube capillaire le guidage et la décélération ont été démontrés. Le piège magnétique mobile est formé par la combinaison d'un champ magnétique quadrupolaire et d'un champ magnétique axial modulé spécialement. Le champ quadrupolaire est continu et un gradient de champ est dirigé seulement dans la direction transverse du jet. Le circuit plan produit une onde magnétique sinusoïdale avec un gradient de champ dans la direction axiale. Avec l'électronique fabriquée au laboratoire, ou peut produire une onde magnétique progressive d'amplitude 0.69T (avec un courant AC de 300A) et de fréquence 40 kHz. On obtient ainsi une onde qui se déplace à une vitesse de 464m/s. Plusieurs expériences de principe ont été réalisées en utilisant le jet froid pulsé d'argon métastable. Nous avons étudié les propriétés de guidage du quadrupole pour divers courants et pour différents atomes (hélium et argon) et comparé les résultats aux prédictions théoriques de simulations numériques. Le jet d'argon métastable a été guidé en 3D à des vitesses variées (464m/s, 400m/s, 392m/s) avec un décélérateur de 28cm de long. La température observée du paquet guidé est de 100mK. L'expérience de décélération a été réalisée avec le jet d'argon métastable depuis la vitesse de 400m/s jusqu'à 370m/s et depuis la vitesse de 392m/s jusqu'à 365m/s. Les résultats expérimentaux sont comparés avec les simulations numériques.
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49

Novotný, Lukáš. "Centrum volnočasových aktivit Brno-Brněnská přehrada." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225603.

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The proposed leisure center building Rowing Club bellows is located in southern part of the Brněnské přehrady between section Rakovec and Kozí horka. The building stands on existing club Lodní sporty Brno in the parcel čp. 1236. The idea of building is a ship sailing on the mainland, whose sails it look like waves. Student accommodation is designed to the second, third and fourth floor. Restaurant and administrative facilities connected to the terrace is designed in the basement. In the first underground floors are designed locker rooms, athletic facilities, kitchen and in the second underground floors is designed rowing pools and rowing boatyards connected to the ground. On the eastern side is a wooden rack tribune. Roads and pavements around the building are designed with simplicity and function.
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50

Patwari, Neal. "Measured and Modeled Time and Angle Dispersion Characteristics of the 1.8 GHz Peer-to-Peer Radio Channel." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/32201.

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In an extensive outdoor propagation study, low antenna heights of 1.7 m are used at both the transmitter and the receiver to measure over 3500 wideband power-delay profiles (PDPs) of the channel for a peer-to-peer communications system. Rural and urban areas are studied in 22 different transmitter-receiver links. The results are used to characterize the narrowband path loss, mean delay, root-mean-square (RMS) delay spread, and timing jitter of the peer-to-peer wideband channel. Small-scale fading characteristics are measured in detail by measuring and analyzing 160 PDPs within each local area. This thesis shows the measurement setup for the calculation of fading rate variance and angular spread and reports the first known attempt to calculate angular spread from track power measurements. New analysis presented in this thesis shows the effect of measurement error in the calculation of angular spread. The expected characteristics of angular spread are derived using two different angle-of-arrival (AOA) models from the literature. Measurement results show initial validation of Durgin's angular spread theory. A new measurement-based algorithm for simulating wideband fading processes is developed and implemented. This simulation technique shows promise in the simulation of high-bit rate peer-to-peer radio communication systems.<br>Master of Science
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