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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Design av mikrovågsövergångar / Design of microwave connections

Petersson, Björn January 2003 (has links)
<p>In this Master thesis, microwave connections between circuit boards are constructed. The primary frequency band is the X-band (8-12 GHz). The purpose of the connections is to enable a more simple and cheaper way of mounting the circuit boards inside a container. </p><p>The connections have been designed and evaluated, using different computer programs. A few prototypes have been built and measured. </p><p>The main goal of this Master thesis was to design a connection, that would be useful in practice. The connections should be easy to manufacture and have a good performance. They should also have a high tolerance for manufacturing errors. </p><p>The main part of this report contains descriptions of different designs. The designs are presented together with simulated and measured results. </p><p>The report contains designs based upon coplanar waveguides and a phase shifting technique. The result shows that designs that are using coplanar waveguides are good. The phase shifting technique has some limitations and need to be developed further.</p>
22

Antenna elements matching : time-domain analysis

Condori-Arapa, Cristina January 2010 (has links)
Time domain analysis in vector network analyzers (VNAs) is a method to represent the frequency response, stated by the S-parameters, in time domain with apparent high resolution. Among other utilities time domain option from Agilent allows to measure microwave devices into a specific frequency range and down till DC as well with the two time domain mode: band-pass and low-pass mode. A special feature named gating is of important as it allows representing a portion of the time domain representation in frequency domain.   This thesis studies the time domain option 010 from Agilent; its uncertainties and sensitivity. The task is to find the best method to measure the antenna element matching taking care to reduce the influence of measurement errors on the results.   The Agilent 8753ES is the instrument used in the thesis. A specific matching problem in the antenna electric down-tilt (AEDT) previously designed by Powerwave Technologies is the task to be solved. This is because it can not be measured directly with 2-port VNAs. It requires adapters, extra coaxial cables and N-connectors, all of which influences the accuracy. The AEDT connects to the array antenna through cable-board-connectors (CBCs). The AEDT and the CBCs were designed before being put into the antenna-system. Their S-parameters do not coincide with the ones measured after these devices were put in the antenna block.   Time domain gating and de-embedding algorithms are two methods proposed in this thesis to measure the S-parameters of the desired antenna element while reducing the influence of measurement errors due to cables CBCs and other connectors. The aim is to find a method which causes less error and gives high confidence measurements.   For the time domain analysis, reverse engineering of the time domain option used in the Agilent VNA 8753ES is implemented in a PC for full control of the process. The results using time-domain are not sufficiently reliable to be used due to the multiple approximations done in the design. The methodology that Agilent uses to compensate the gating effects is not reliable when the gate is not centered on the analyzed response. Big errors are considered due to truncation and masking effects in the frequency response.   The de-embedding method using LRL is implemented in the AEDT measurements, taking away the influences of the CBCs, coaxial cables and N-connector. It is found to have sufficient performance, comparable to the mathematical model. Error analysis of both methods has been done to explaine the different in measurements and design.
23

Design av mikrovågsövergångar / Design of microwave connections

Petersson, Björn January 2003 (has links)
In this Master thesis, microwave connections between circuit boards are constructed. The primary frequency band is the X-band (8-12 GHz). The purpose of the connections is to enable a more simple and cheaper way of mounting the circuit boards inside a container. The connections have been designed and evaluated, using different computer programs. A few prototypes have been built and measured. The main goal of this Master thesis was to design a connection, that would be useful in practice. The connections should be easy to manufacture and have a good performance. They should also have a high tolerance for manufacturing errors. The main part of this report contains descriptions of different designs. The designs are presented together with simulated and measured results. The report contains designs based upon coplanar waveguides and a phase shifting technique. The result shows that designs that are using coplanar waveguides are good. The phase shifting technique has some limitations and need to be developed further.
24

Bedömning av investeringar i ny teknik på elmarknaden : Utveckling av ett indikatorsystem och praktisk applicering / A multi criteria analysis tool for evaluation of investments in new technology

Arding, Karin, In de Betou, Siri January 2021 (has links)
The aim of this thesis is to create a tool which quantifies qualitative measures into an indicator system. The system is created on behalf of a company which is associated with investments in new technologies on the energy market. The indicator system is to take into consideration important factors in the first part of an investment cycle, in other words, the screening phase. Qualitative measures will, in each indicator, become quantified and will together create a weighted grade on a potential investment that can help the investor decide whether or not to move forward with said investment. The aim of the thesis is also to evaluate the indicator system on current possible investment options in order to analyse and discuss how the final product will work in the investor company ́s actual context. The method consists of two main parts, a gap analysis which is conducted within the investor company and its owners and a compilation of which indicators that are of greatest importance in a screening phase according to earlier research. The main result of the study is the full indicator system which consist of four indicators: technology readiness of the potential investment, contextual analysis of the potential investment, diversity within the company and the financial burn rate of the company. When applied to current potential investments the result showed that there was negligible to moderate correlation between the indicators, which was important for the system to be validated. It was also concluded that a potential investment should exceed 60 percent of the possible maximum grade in order to pass through the screening phase. The results also showed that there were four apparent gaps, namely consensus between the involved actors, utilization rate of the organizations competencies, to enter new markets and the right competency to do so. The future potential investments of the investor company should therefore aim to fill in these gaps in order to strengthen the role of the company. If doing so while using the indicator system, the risks of choosing investment options that does not fit into the investor company ́s context, will be minimized.
25

Hyperloop in Sweden : Evaluating Hyperloops Viability in the Swedish Context / Hyperloop i Sweden : Utvärdering av Hyperloops Möjligheter i den Svenska Kontexten

Magnusson, Fredrik, Widegren, Fredrik January 2018 (has links)
Transportations role in society is increasingly important and today it has a prominent role in business, citizens lives as well as in the world economy. The increasing globalization and urbanization puts significant pressure on the existing transport system, with increasing demand for high-speed travel. However, this comes with implications on the environment, and the environmental concerns constitutes one of the biggest pressures in transport. And as the contemporary modes are bound by their technologies, enabling marginal rather than radical improvements, a possible window of opportunity for new radical technologies to enter the market can emerge. One new technology emerging within transportation today is called hyperloop, a technology that could prove to meet demand for faster, cheaper, safer and more environmentally efficient transportation. However, the technology is still in an early stage of development and hence surrounded by major uncertainties. Further, the nature of the technology necessitates overcoming several obstacles before it can reach commercial practice. And this together with a limited knowledge of the concept in Sweden makes it difficult to predict if hyperloop can become a viable transport alternative on the Swedish market. Which condensed lays the foundation to the purpose of this paper: "To give an overarching understanding of the Swedish transport market dynamics, together with a comprehensive evaluation of the hyperloop concept. And hence contribute to more inclusive knowledge and understanding of hyperloop’s viability in the Swedish context." Since the phenomenon has not been comprehensively studied previously, the elected research design is that of an exploratory case study, with an inductive, qualitative approach. To address the purpose, a literary review of the theoretical field was conducted. Looking in to previous research on disruptive innovation, diffusion of innovations, technical transitions, transformational pressure as well as window of opportunity. The empirical material gathered during the research process was derived from two main channels. Firstly, an extensive review of scientific articles about the hyperloop technology was conducted, providing insights on the technology and its surroundings. This was complemented by qualitative interviews to obtain material on the dynamics of the Swedish transport market as well as for understanding hyperloop in the Swedish context. The empirical study was further accompanied by a review of news articles and websites to map the most recent progress in the hyperloop development. By analyzing the empirical material through three frameworks; Characteristics of Diffusion, the Multi-Level Perspective (MLP) and Technology Readiness Level (TRL), interesting findings and conclusions were drawn. These together points towards that hyperloop, if the technology reaches its predicted performance, will have significant relative advantages and observable effects in the relation to the contemporary modes of transportation. Further, a noticeable window of opportunity, sprung from capacity shortages and pressure towards environmental sustainability, seems to exist on the Swedish market. A window which could be capitalized upon and justify hyperloop in the Swedish context. The current state of the technology does however come with implications as it so far is insufficient to decrease uncertainty amongst the potential adopters. Factors that likely will prolong the adoption of the technology in Sweden relates to the relative complexity of the system, its limited compatibility with existing practices and the low maturity of the technology. Hence, the hyperloop companies must prove the concept feasible and increase the maturity to gain sufficient acceptance and recognition. This paper contributes to the academic community by assessing the compatibility of hyperloop on the Swedish market, as well as if hyperloop could become a viable alternative transport solution in Sweden. It provides insight to specific perspectives of the Swedish market, its requirements and the demand for alternative transport solutions. Hence, this paper is considered to make both an analytical contribution in terms of evaluating the viability of disruptive technologies. And an empirical contribution by shedding light on new important insights for the potential diffusion of hyperloop. Insights that are significant for hyperloop actors as well as for dominant actors on the Swedish transport market. / Transporters roll i samhället blir allt viktigare och de har idag en framträdande roll inom näringsliv, medborgares liv samt världsekonomin. Den ökande globaliseringen och urbaniseringen sätter dock ett betydande tryck på det existerande transportsystemet, med ökande efterfrågan för höghastighetsalternativ. Detta medför implikationer för miljön, och oron kring transporters miljöpåverkan är ett av de största bekymren för transportsektorn. Eftersom de existerande transportalternativen är bundna av sin teknik, vilket begränsar dem till inkrementella snarare än radikala förbättringar, kan en möjlighet för nya transportsätt att komma in på marknaden öppna sig. En kommande ny teknik som utvecklas inom transport idag kallas hyperloop, en teknik som kan visa sig möta efterfrågan för snabbare, billigare, säkrare och mer miljösmarta transporter. Tekniken är dock i ett tidigt utvecklingsskede och är därav omgärdad av stora osäkerheter. Vidare kräver teknikens natur att flertalet hinder kommer att behöva överkommas innan tekniken kan nå kommersiellt bruk. Detta tillsammans med den begränsade kunskap som finns kring konceptet i Sverige gör det svårt att förutspå om hyperloop kan bli ett möjligt transportalternativ på den svenska marknaden. Kondenserat ligger detta till grund för syftet med den här uppsatsen: "Att ge en övergripande förståelse av dynamiken på den svenska transportmarknaden, tillsammans med en djupgående utvärdering av hyperloop konceptet. Och därav bidra till en mer inkluderande kunskap och förståelse kring hyperloops möjligheter i den svenska kontexten." Eftersom detta fenomen inte tidigare har studerats i större utsträckning valdes en forskningsdesign i form av en undersökande fallstudie med ett induktivt, kvalitativt tillvägagångssätt. För att adressera syftet gjordes en litterär översyn av det teoretiska fältet. Med inblickar i tidigare forskning kring disruptiv teknik, diffusion av innovation, tekniska övergångar, transformationstryck samt möjlighetsfönster. Det empiriska materialet till studien samlades in genom två kanaler i huvudsak. Först, genom en djupdykning i tidigare forskning och vetenskapliga artiklar relaterade till hyperlooptekniken, för att generera insikter kring tekniken och dess omgivning. Detta kompletteras med kvalitativa intervjuer för att erhålla material om dynamiken på den svenska transportmarknaden samt för att ge en förståelse av hyperloop i den svenska kontexten. Den empiriska studien kompletterades ytterligare med en översyn av nyhetsartiklar och webbplatser för att kartlägga de senaste framstegen i hyperlooputvecklingen. Genom att analysera det empiriska materialet med hjälp av tre ramverk; Egenskaper för Spridning av Innovation, Perspektiv i Multipla Nivåer (MLP) och Teknisk Mogenhetsnivå (TRL), kunde flertalet intressanta upptäckter och slutsatser dras. Vilka tillsammans pekar mot att hyperloop, om tekniken lyckas uppnå den predikterade prestandan, kommer att ha betydande relativa fördelar och synliga effekter i förhållande till dagens transportsätt. Vidare kan ett märkbart möjlighetsfönster, sprunget ur kapacitetsbrist och tryck mot miljömässig hållbarhet, identifieras på den svenska marknaden. Detta fönster skulle kunna kapitaliseras på och motivera hyperloop i den svenska kontexten. Teknologins nuvarande tillstånd har emellertid konsekvenser, eftersom den hittills inte är tillräcklig för att minska osäkerheten hos potentiella adopterare. Faktorer som sannolikt kommer att förlänga processen att adoptera tekniken i Sverige härstammar från systemets relativa komplexitet, dess begränsade kompatibilitet med befintliga metoder samt teknikens låga mogenhet. Därav är det essentiellt för hyperloopbolagen att bevisa konceptet möjligt och öka mogenheten för att få tillräcklig acceptans och erkännande. Detta arbete bidrar till det akademiska samhället genom att bedöma kompatibiliteten mellan hyperloop och den svenska marknaden, samt om hyperloop kan bli ett genomförbart transportalternativ i Sverige. Arbetet bidrar med insikter i specifika perspektiv på den svenska marknaden, dess krav samt efterfrågan för alternativa transportlösningar. Därav kan denna uppsats anses utgöra både ett analytiskt bidrag genom dess utvärdering av genomförbarheten av disruptiv teknik. Samt ett empiriskt bidrag genom att belysa viktiga insikter för den potentiella spridningen av hyperloop. Insikter som är viktiga för såväl hyperloopaktörer som de dominanta aktörerna på den svenska transportmarknaden.
26

Analysis and design of efficient passive components for the millimeter-wave and THz bands

Berenguer Verdú, Antonio José 29 June 2017 (has links)
This thesis tackles issues of particular interest regarding analysis and design of passive components at the mm-wave and Terahertz (THz) bands. Innovative analysis techniques and modeling of complex structures, design procedures, and practical implementation of advanced passive devices are presented. The first part of the thesis is dedicated to THz passive components. These days, THz technology suffers from the lack of suitable waveguiding structures since both, metals and dielectric, are lossy at THz frequencies. This implies that neither conventional closed metallic structures used at microwave frequencies, nor dielectric waveguides used in the optical regime, are adequate solutions. Among a variety of new proposals, the Single Wire Waveguide (SWW) stands out due to its low attenuation and dispersion. However, this surface waveguide presents difficult excitation and strong radiation on bends. A Dielectric-Coated Single Wire Waveguide (DCSWW) can be used to alleviate these problems, but advantages of the SWW are lost and new problems arise. Until now, literature has not given proper solution to radiation on bends and, on the other hand, rigorous characterization of these waveguides lacks these days. This thesis provides, for the first time, a complete modal analysis of both waveguides, appropriated for THz frequencies. This analysis is later applied to solve the problem of radiation on bends. Several structures and design procedures to alleviate radiation losses are presented and experimentally validated. The second part of the thesis is dedicated to mm-wave passive components. These days, when implementing passive components to operate at such small, millimetric wavelengths, to ensure proper metallic contact and alignment between parts results challenging. In addition, dielectric absorption becomes significant at mm-wave frequencies. Consequently, conventional hollow metallic waveguides and planar transmission lines present high attenuation so that new topologies are being considered. Gap Waveguides (GWs), based on a periodic structure introducing an Electromagnetic Bandgap effect, result very suitable since they do not require metallic contacts and avoid dielectric losses. However, although GWs have great potential, several issues prevent GW technology from becoming consolidated and universally used. On the one hand, the topological complexity of GWs difficulties the design process since full-wave simulations are time-costly and there is a lack of appropriate analysis methods and suitable synthesis procedures. On the other hand, benefits of using GWs instead of conventional structures are required to be more clearly evidenced with high-performance GW components and proper comparatives with conventional structures. This thesis introduces several efficient analysis methods, models, and synthesis techniques that will allow engineers without significant background in GWs to straightforwardly implement GW devices. In addition, several high-performance narrow-band filters operating at Ka-band and V-band, as well as a rigorous comparative with rectangular waveguide topology, are presented. / Esta tesis aborda problemas actuales en el análisis y diseño de componentes pasivos en las bandas de onda milimétrica y Terahercios (THz). Se presentan nuevas técnicas de análisis y modelado de estructuras complejas, procedimientos de diseño, e implementación práctica de dispositivos pasivos avanzados. La primera parte de la tesis se dedica a componentes pasivos de THz. Actualmente no se disponen de guías de onda adecuadas a THz debido a que ambos, metales y dieléctricos, introducen grandes pérdidas. En consecuencia, no es adecuado escalar las estructuras metálicas cerradas usadas en microondas, ni las guías dieléctricas usadas a frecuencias ópticas. Entre un gran número de recientes propuestas, la Single Wire Waveguide (SWW) destaca por su baja atenuación y casi nula dispersión. No obstante, como guía superficial, la SWW presenta difícil excitación y radiación en curvas. El uso de un recubrimiento dieléctrico, creando la Dielecric-Coated Single Wire Waveguide (DCSWW), alivia estos inconvenientes, pero las ventajas anteriores se pierden y nuevos problemas aparecen. Hasta la fecha, no se han encontrado soluciones adecuadas para la radiación en curvas de la SWW. Además, se echa en falta una caracterización rigurosa de ambas guías. Esta tesis presenta, por primera vez, un análisis modal completo de SWW y DCSWW, adecuado a la banda de THz. Este análisis es aplicado posteriormente para evitar el problema de la radiación en curvas. Se presentan y validan experimentalmente diversas estructuras y procedimientos de diseño. La segunda parte de la tesis abarca componentes pasivos de ondas milimétricas. Actualmente, estos componentes sufren una importante degradación de su respuesta debido a que resulta difícil asegurar contacto metálico y alineamiento adecuados para la operación a longitudes de onda tan pequeñas. Además, la absorción dieléctrica incrementa notablemente a estas frecuencias. En consecuencia, tanto guías metálicas huecas como líneas de transmisión planares convencionales presentan gran atenuación, siendo necesario considerar topologías alternativas. Las Gap Waveguides (GWs), basadas en una estructura periódica que introduce un efecto de Electromagnetic Bandgap, resultan muy adecuadas puesto que no requieren contacto entre partes metálicas y evitan las pérdidas en dieléctricos. No obstante, a pesar del potencial de las GWs, varias barreras impiden la consolidación y uso universal de esta tecnología. Por una parte, la compleja topología de las GWs dificulta el proceso de diseño dado que las simulaciones de onda completa consumen mucho tiempo y no existen actualmente métodos de análisis y diseño apropiados. Por otra parte, es necesario evidenciar el beneficio de usar GWs mediante dispositivos GW de altas prestaciones y comparativas adecuadas con estructuras convencionales. Esta tesis presenta diversos métodos de análisis eficientes, modelos, y técnicas de diseño que permitirán la síntesis de dispositivos GW sin necesidad de un conocimiento profundo de esta tecnología. Asimismo, se presentan varios filtros de banda estrecha operando en las bandas Ka y V con altas prestaciones, así como una comparativa rigurosa con la guía rectangular. / Aquesta tesi aborda problemes actuals en relació a l'anàlisi i disseny de components passius en les bandes d'ona mil·limètrica i Terahercis. Es presenten noves tècniques d'anàlisi i modelatge d'estructures complexes, procediments de disseny, i implementació pràctica de dispositius passius avançats. La primera part de la tesi es focalitza en components passius de THz. Actualment no es disposen de guies d'ona adequades a THz causa que tots dos, metalls i dielèctrics, introdueixen grans pèrdues. En conseqüència, no és adequat escalar les estructures metál·liques tancades usades en microones, ni les guies dielèctriques usades a freqüències òptiques. Entre un gran nombre de propostes recents, la Single Wire Waveguide (SWW) destaca per la seua baixa atenuació i quasi nul·la dispersió. No obstant això, com a guia superficial, la SWW presenta difícil excitació i radiació en corbes. L'ús d'un recobriment dielèctric, creant la Dielecric-Coated Single Wire Waveguide (DCSWW), alleuja aquests inconvenients, però els avantatges anteriors es perden i nous problemes apareixen. Fins a la data, no s'han trobat solucions adequades per a la radiació en corbes de la SWW. A més, es troba a faltar una caracterització rigorosa d'ambdues guies. Aquesta tesi presenta, per primera vegada, un anàlisi modal complet de SWW i DCSWW, adequat a la banda de THz. Aquest anàlisi és aplicat posteriorment per evitar el problema de la radiació en corbes. Es presenten i validen experimentalment diverses estructures i procediments de disseny. La segona part de la tesi es centra en components passius d'ones mil·limètriques. Actualment, aquests components pateixen una important degradació de la seua resposta a causa de que resulta difícil assegurar contacte metàl·lic i alineament adequats per a l'operació a longituds d'ona tan menudes. A més, l'absorció dielèctrica incrementa notablement a aquestes freqüències. En conseqüència, tant guies metàl·liques buides com línies de transmissió planars convencionals presenten gran atenuació, sent necessari considerar topologies alternatives. Les Gap Waveguides (GWs), basades en una estructura periòdica que introdueix un efecte de Electromagnetic Bandgap, resulten molt adequades ja que no requereixen contacte entre parts metàl·liques i eviten les pèrdues en dielèctrics. No obstant, tot i el potencial de les GWs, diverses barreres impedixen la consolidació i ús universal d'aquesta tecnologia. D'una banda, la complexa topologia de les GWs dificulta el procés de disseny atés que les simulacions d'ona completa consumeixen molt de temps i no existeixen actualment mètodes d'anàlisi i disseny apropiats. D'altra banda, és necessari evidenciar el benefici d'utilitzar GWs mitjançant dispositius GW d'altes prestacions i comparatives adequades amb estructures convencionals. Aquesta tesi presenta diversos mètodes d'anàlisi eficients, models, i tècniques de disseny que permetran la síntesi de dispositius GW sense necessitat d'un coneixement profund d'aquesta tecnologia. Així mateix, es presenten diversos filtres de banda estreta operant en les bandes Ka i V amb altes prestacions, així com una comparativa rigorosa amb la guia rectangular. / Berenguer Verdú, AJ. (2017). Analysis and design of efficient passive components for the millimeter-wave and THz bands [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/84004 / TESIS

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