Siga este enlace para ver otros tipos de publicaciones sobre el tema: Microwave networks.
Tesis sobre el tema "Microwave networks"
Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros
Consulte los 50 mejores tesis para su investigación sobre el tema "Microwave networks".
Junto a cada fuente en la lista de referencias hay un botón "Agregar a la bibliografía". Pulsa este botón, y generaremos automáticamente la referencia bibliográfica para la obra elegida en el estilo de cita que necesites: APA, MLA, Harvard, Vancouver, Chicago, etc.
También puede descargar el texto completo de la publicación académica en formato pdf y leer en línea su resumen siempre que esté disponible en los metadatos.
Explore tesis sobre una amplia variedad de disciplinas y organice su bibliografía correctamente.
1
Mohammad, Malik Adeel y Saeed Muhammad Sheharyar. "Load Balancing in Microwave Networks". Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-121698.
Texto completoResumen
Microwave links are very commonly used in carrier networks especially towards the access side. They not only ease deployment of a network but are also very cost effective. However, they bring along a multitude of challenges which are characteristic of the wireless technology. Microwave links are fickle. Being exposed to varying weather conditions, they experience bandwidth fluctuations. This is true especially in the case of links operating at higher frequencies. The unpredictable nature of microwave links makes it quite challenging to plan capacity in a network beforehand. Radio links employ adaptive modulation. They operate on a range on modulation schemes each of which offers different throughput and bit error rates. When operating at a low bit rate modulation scheme, a situation may arise where the microwave link is not able to support the entire traffic incident from the backbone network. As a result, the microwave link will suffer from congestion and packets arriving at the microwave link will eventually be dropped. The switching nodes that precede the microwave link along a communication path are unaware of the microwave link conditions and, therefore, continue to transmit traffic at a high rate. Large carrier networks cannot afford to have performance inconsistencies like data loss and increased latency. Service degradation, even for a very short duration, can have dire consequences in terms of customer dissatisfaction and revenue loss. The goal of this thesis is to use MPLS-TP Linear Protection to load balance traffic across alternative paths in a network where links use adaptive modulation. Rerouted traffic must take other paths so that the congested microwave link is completely avoided. The idea is augmented by the use of a radio condition signaling mechanism between the packet switching node and the microwave node that precede a microwave link. The microwave node sends radio condition control messages to the preceding packet switching node to rate limit traffic and avoid congestion at the microwave link. The result of this thesis work is a system prototype that achieves the stated goal. Evaluation of the prototype is carried out through graphical results, generated by a traffic generator, that advocate the correctness, performance and robustness of the system.
2
McKenzie, Wilfred. "Characterisation of microwave passive networks based on electromagnetic analysis". Thesis, University of Leeds, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278080.
Texto completo
3
Wang, Fang. "Knowledge based neural networks for microwave modeling and design". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ37081.pdf.
Texto completo
4
Dias, De Macedo Filho Antonio. "Microwave neural networks and fuzzy classifiers for ES systems". Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.244066.
Texto completo
5
Wang, Fang Carleton University Dissertation Engineering Electronics. "Knowledge based neural networks for microwave modeling and design". Ottawa, 1998.
Buscar texto completo
6
Basarudin, Hafiz. "Development of a heterogeneous microwave network, fade simulation tool applicable to networks that span Europe". Thesis, University of Hull, 2012. http://hydra.hull.ac.uk/resources/hull:5774.
Texto completoResumen
Radio communication systems operating at microwave frequencies are strongly attenuated by hydrometeors such as rain and wet snow (sleet). Hydrometeor attenuation dominates the dynamic fading of most types of radio links operating above 10 GHz, especially high capacity, fixed, terrestrial and Earth-Space links. The International Telecommunication Unions – Radio Section (ITU-R) provides a set of internationally recognized models to predict annual fade distributions for a wide variety of individual radio link. However, these models are not sufficient for the design and optimisation of networks, even as simple as two links. There are considerable potential gains to be achieved from the optimized design of real-time or predictive Dynamic Resource Management systems. The development of these systems requires a joint channel simulation tool applicable to arbitrary, heterogeneous networks. This thesis describes the development of a network fade simulation tool, known as GINSIM, which can simulate joint dynamic fade time-series on heterogeneous networks of arbitrary geometry, spanning Europe. GINSIM uses as input meteorological and topological data from a variety of sources and numerically calculates the joint effects on fading on all links in a specified network. ITU-R models are used to transform rain rate into specific attenuation and to estimate the specific attenuation amplification due to non-liquid hydrometeors. The resulting simulation tool has been verified against ITU-R models of average annual fade distributions, fade slope and fade duration distributions, in the southern UK. Validation has also been performed against measured terrestrial and Earth-space link data, acquired in the Southern UK and Scotland.
7
Muñoz-Arcos, Christian Daniel. "Optical Microwave Signal Generation for Data Transmission in Optical Networks". Thesis, Toulouse, ISAE, 2020. http://www.theses.fr/2020ESAE0013.
Texto completoResumen
La croissance des services de télécommunications et l’augmentation du trafic de données àl’échelle mondiale favorise le développement et l’intégration de différents réseaux de transmissionde données. Un exemple de ce développement est constitué par les réseaux defibres optiques, qui sont actuellement chargés d’interconnecter les continents par des liaisonslongues avec des taux de transfert importants. Les réseaux optiques, ainsi que les réseauxsupportés par d’autres moyens de transmission, utilisent des signaux électriques à certainesfréquences pour la synchronisation des éléments du réseau. La qualité de ces signaux est unfacteur décisif dans la performance globale du système, c’est pourquoi leur bruit de phasedoit ˆetre aussi faible que possible.Ce document décrit la conception et la mise en œuvre d’un système optoélectronique pour lagénération de signaux micro-ondes à l’aide de diodes laser à cavité verticale (VCSEL) et sonintégration dans un système de transmission optique de données. Compte tenu du fait que lesystème proposé intègre un laser VCSEL directement modulé, une caractérisation théoriqueet expérimentale a été élaborée sur la base des équations d’évolution du laser, de mesuresdynamiques et statiques, et d’un modèle électrique équivalent de la région active. Cetteméthode a permis l’extraction de certains paramètres intrinsèques du VCSEL, ainsi que lavalidation et la simulation de ses performances dans différentes conditions de modulation.Le VCSEL utilisé émet en bande C et a été sélectionné en considérant que cette bande estcouramment utilisée dans les liaisons à longue distance.Le système proposé est constitué d’une boucle fermée qui déclenche l’oscillation grâce auxsources de bruit des composants et module le VCSEL en fort signal pour générer des impulsionsoptiques (gain switching). Ces impulsions optiques, qui dans le domaine des fréquencescorrespondent à un peigne de fréquences optiques, sont détectées pour générer simultanémentune fréquence fondamentale (déterminée par un filtre passe-bande) et plusieurs harmoniques.Le bruit de phase mesuré à10 kHz de la porteuse à1,25 GHz est de -127,8 dBc/Hz, etconstitue la valeur la plus faible signalée dans la littérature pour cette fréquence et cette architecture.La gigue et la largeur d’impulsion optique ont été déterminées lorsque différentescavités résonantes et différents courants de polarisation étaient utilisés. La durée d’impulsionThe massive growth of telecommunication services and the increasing global data traffic boostthe development, implementation, and integration of different networks for data transmission.An example of this development is the optical fiber networks, responsible today for theinter-continental connection through long-distance links and high transfer rates. The opticalnetworks, as well as the networks supported by other transmission media, use electricalsignals at specific frequencies for the synchronization of the network elements. The qualityof these signals is usually determined in terms of phase noise. Due to the major impact ofthe phase noise over the system performance, its value should be minimized.The research work presented in this document describes the design and implementation ofan optoelectronic system for the microwave signal generation using a vertical-cavity surfaceemittinglaser (VCSEL) and its integration into an optical data transmission system. Consideringthat the proposed system incorporates a directly modulated VCSEL, a theoreticaland experimental characterization was developed based on the laser rate equations, dynamicand static measurements, and an equivalent electrical model of the active region. This proceduremade possible the extraction of some VCSEL intrinsic parameters, as well as thevalidation and simulation of the VCSEL performance under specific modulation conditions.The VCSEL emits in C-band, this wavelength was selected because it is used in long-haullinks. The proposed system is a self-initiated oscillation system caused by internal noise sources,which includes a VCSEL modulated in large signal to generate optical pulses (gain switching).The optical pulses, and the optical frequency comb associated, generate in electricaldomain simultaneously a fundamental frequency (determined by a band-pass filter) and severalharmonics. The phase noise measured at 10 kHz from the carrier at 1.25 GHz was -127.8dBc/Hz, and it is the lowest value reported in the literature for this frequency and architecture.Both the jitter and optical pulse width were determined when different resonantcavities and polarization currents were employed. The lowest pulse duration was 85 ps andwas achieved when the fundamental frequency was 2.5 GHz. As for the optical frequencycomb, it was demonstrated that its flatness depends on the electrical modulation conditions.The flattest profiles are obtained when the fundamental frequency is higher than the VCSELrelaxation frequency. Both the electrical and the optical output of the system were integrated into an optical transmitter.The electrical signal provides the synchronization of the data generating equipment,whereas the optical pulses are employed as an optical carrier. Data transmissions at 155.52Mb/s, 622.08 Mb/s and 1.25 Gb/s were experimentally validated. It was demonstrated thatthe fundamental frequency and harmonics could be extracted from the optical data signaltransmitted by a band-pass filter. It was also experimentally proved that the pulsed returnto-zero (RZ) transmitter at 1.25 Gb/s, achieves bit error rates (BER) lower than 10−9 whenthe optical power at the receiver is higher than -33 dBm. la plus faible, 85 ps, a été obtenue lorsque la fréquence fondamentale du système était de 2,5 GHz. En ce qui concerne le peigne de fréquences optiques, il a été démontré que la formedu peigne dépend des conditions de modulation électrique et que les profils les plus platssont obtenus lorsque la fréquence fondamentale est supérieure à la fréquence de relaxationdu VCSEL. Les sorties électrique et optique du système ont été intégrées dans un émetteur optique. Lesignal électrique permet la synchronisation de l’équipement responsable de la génération desdonnées, tandis que les impulsions optiques sont utilisées comme porteuse optique. La transmissionde données à 155,52 Mb/s, 622,08 Mb/s et 1,25 Gb/s a été validée expérimentalement
8
Hedrick, Jeffrey C. "High performance polymeric networks and thermoplastic blends : microwave versus thermal processing /". Diss., This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-07122007-103925/.
Texto completoResumen
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991.Vita. Abstract. No film copy made for this title. Includes bibliographical references (leaves 243-254). Also available via the Internet.
9
Lochtie, Gail D. "Propagation at microwave frequencies in the presence of tropospheric stratified layers". Thesis, University of Essex, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303451.
Texto completo
10
Pratap, Rana Jitendra. "Design and Optimization of Microwave Circuits and Systems Using Artificial Intelligence Techniques". Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7225.
Texto completoResumen
In this thesis, a new approach combining neural networks and genetic algorithms is presented for microwave design. In this method, an accurate neural network model is developed from the experimental data. This neural network model is used to perform sensitivity analysis and derive response surfaces. An innovative technique is then applied in which genetic algorithms are coupled with the neural network model to assist in synthesis and optimization. The proposed method is used for modeling and analysis of circuit parameters for flip chip interconnects up to 35 GHz, as well as for design of multilayer inductors and capacitors at 1.9 GHz and 2.4 GHz. The method was also used to synthesize mm wave low pass filters in the range of 40-60 GHz. The devices obtained from layout parameters predicted by the neuro-genetic design method yielded electrical response close to the desired value (95% accuracy). The proposed method also implements a weighted priority scheme to account for tradeoffs in microwave design. This scheme was implemented to synthesize bandpass filters for 802.11a and HIPERLAN wireless LAN applications in the range of 5-6 GHz.
This research also develops a novel neuro-genetic design centering methodology for yield enhancement and design for manufacturability of microwave devices and circuits. A neural network model is used to calculate yield using Monte Carlo methods. A genetic algorithm is then used for yield optimization. The proposed method has been used for yield enhancement of SiGe heterojunction bipolar transistor and mm wave voltage-controlled oscillator. It results in significant yield enhancement of the SiGe HBTs (from 25 % to 75 %) and VCOs (from 8 % to 85 %). The proposed method is can be extended for device, circuit, package, and system level integrated co-design since it can handle a large number of design variables without any assumptions about the component behavior. The proposed algorithm could be used by microwave community for design and optimization of microwave circuits and systems with greater accuracy while consuming less computational time.
11
Murphy, Ethan Kane. "Radial-Basis-Function Neural Network Optimization of Microwave Systems". Digital WPI, 2003. https://digitalcommons.wpi.edu/etd-theses/77.
Texto completoResumen
An original approach in microwave optimization, namely, a neural network procedure combined with the full-wave 3D electromagnetic simulator QuickWave-3D implemented a conformal FDTD method, is presented. The radial-basis-function network is trained by simulated frequency characteristics of S-parameters and geometric data of the corresponding system. High accuracy and computational efficiency of the procedure is illustrated for a waveguide bend, waveguide T-junction with a post, and a slotted waveguide as a radiating element.
12
Murphy, Ethan Kane. "Radial-Basis-Function Neural Network Optimization of Microwave Systems". Link to electronic thesis, 2002. http://www.wpi.edu/Pubs/ETD/Available/etd-0113103-121206/.
Texto completoResumen
Master's Project (M.S.) -- Worcester Polytechnic Institute.Keywords: optimization technique; microwave systems; optimization technique; neural networks; QuickWave 3D. Includes bibliographical references (p. 68-71).
13
Mohammadi, Abbas. "A direct microwave M-QAM adaptive transmitter for fixed wireless ATM networks". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0012/NQ37899.pdf.
Texto completo
14
Xi, Changgeng. "Optimization approaches to the training of neural networks with RF/microwave applications". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0018/MQ48465.pdf.
Texto completo
15
Xi, Changgeng Carleton University Dissertation Engineering Electronics. "Optimization approaches to the training of neural networks with RF/microwave applications". Ottawa, 1999.
Buscar texto completo
16
Rayas-Sanchez, Jose Ernesto. "Neural space mapping methods for modeling and design of microwave circuits /". *McMaster only, 2001.
Buscar texto completo
17
U-yen, Kongpop. "Microwave filters with high stop-band performance and low-loss hybrid developement". Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-11162006-111102/.
Texto completoResumen
Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2007.Tentzeris, Manos, Committee Member ; Wollack, Edward, Committee Member ; Cressler, John, Committee Member ; Papapolymerou, Ioannis, Committee Chair ; Laskar, Joy, Committee Co-Chair ; Ayazi, Farrokh, Committee Member.
18
Welton, Sean P. "Load Modulation Through Varactor Tunable Matching Networks". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306865537.
Texto completo
19
Maule, Charles Stephen Marks Robert J. "Principal component and neural network calibration of a microwave frequency composition measurement sensor". Waco, Tex. : Baylor University, 2007. http://hdl.handle.net/2104/5113.
Texto completo
20
Kilic, Ozgehan. "Defected Ground Structure And Its Applications To Microwave Devices And Antenna Feed Networks". Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612415/index.pdf.
Texto completoResumen
This thesis reports the analysis of the rectangular shaped defected ground structure
(RS-DGS) and the application of the structure on some microwave devices. DGS is analyzed
in terms of its superior properties, which enables the designers to easily realize
many kind of microwave devices which are impossible to achieve with the standard applications.
Within the scope of this thesis, the focus is on the rectangular shaped DGS
and its characteristic properties. The basic slow wave and high impedance characteristics
are utilized in the design of some microwave devices. The design is carried on at the two
different frequency bands: X-band and Ka band, centering at 10 GHz and 35 GHz, respectively.
Finally, using the high impedance property and the coupling between the
defects, a wide band 1 : 4 beam forming network is designed and implemented at
10 GHz.
21
Temir, Kaan. "True-time Delay Structures For Microwave Beamforming Networks In S-band Phased Arrays". Master's thesis, METU, 2013. http://etd.lib.metu.edu.tr/upload/12615386/index.pdf.
Texto completoResumen
True time delay networks are one of the most critical structures of wideband phased-array antenna systems which are frequently used in self-protection and electronic warfare applications. In order to direct the main beam of a wideband phased-array antenna to the desired directionphase values, which are linearly dependent to frequency, are essential. Due to the phase characteristics of the true-time delay networks, beam squint problems for broadband phased array systems are minimized. In this thesis, different types of true-time delay structures are investigated for wideband phased array applications and a tunable S-band true-time delay network having delay over 1ns with high resolution is developed, designed, fabricated and measured. Lower-cost, smaller occupied area, digital/analog control mechanism and ease of implementation are the other features of the developed network. High delay values with high resolutions for wideband operation are achieved through the combination of several techniques
therefore the desired S-band TTD network is constructed with the synthesis of switched-transmission lines, constant-R networks and periodically-loaded transmission lines. Higher delay states are realized by the switched-transmission lines technique, while the method of constant R-network is used for the intermediate delay states. To increase the tuning flexibility, smaller delay states are accomplished by analog-voltage controlled periodically loaded transmission lines. A step-by-step procedure is followed during the design process of the S-band true time delay network. Firstly, each method used in the TTD network is analyzed in detail and developed for PCB implementation and the use of COTS components. Then, the designed structures are verified via linear and EM simulations performed by ADS2011®
. After that, the effects of production tolerances are examined to optimize each design for S-band operations. Moreover, the designed structures are fabricated by using PCB technology and measured. Finally, a software code is developed in MATLAB to generate the overall cascaded network with the help of measured data.
22
Lorilla, Lorenzo M. 1981. "Filtering techniques for mitigating microwave oven interference on 802.11b wireless local area networks". Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/16980.
Texto completoResumen
Thesis (M.Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.Includes bibliographical references (p. 165-169).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
With the increasing popularity and assimilation of wireless devices into the everyday lives of people, the issue of their feasibility for coexisting with other radio frequency (RF) devices arises. Particularly strong interferers for the IEEE 802.11b standard are microwave ovens, since both operate at 2.4 GHz. The interference mitigation techniques all exploit the differences between the interference and the signal, since the former is sinusoidal in nature while the latter can be viewed as noise. The first mitigation filter operates in the frequency domain and filters the received signal's Fast Fourier Transform (FFT) sequence by detecting and removing peak sinusoidal components over the flat 3- dB bandwidth of the signal. The second is a Least Mean Square (LMS) Adaptive filter that produces an estimate of the interference through a recursive approximation method and subtracts it out from the received signal. The third and last is the Adaptive Notch Filter (ANF) which implements a lattice structure and has a time-varying notch frequency parameter that converges to and tracks the frequency of the interference in the received signal. The three filters are shown to produce improvements in the bit error rate (BER) and frame error rate (FER) performance of the receiver under various relative strengths of the signal with respect to the interference.
by Lorenzo M. Lorilla.
M.Eng.and S.B.
23
Cascio, Lucia. "Modeling of nonlinear active and passive devices in three-dimensional TLM networks". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0003/NQ34254.pdf.
Texto completo
24
Huang, Xin. "Multi-channel security protocols in personal networks". Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:e0217f2f-4b8f-4ee4-bb34-03cd03e6f68b.
Texto completoResumen
Personal computing devices are becoming more and more popular. These devices are able to collaborate with each other using wireless communication technologies, and then support many applications. Some interesting examples of these are healthcare, context-aware computing, and sports training. In any such applications, security is of vital importance. Firstly, sensitive personal data is always collected in these applications, thus confidentiality is usually required. Secondly, authenticity and integrity of data or instructions are always critical; incorrect data or instructions are not only useless, but also harmful in some cases. This thesis analyses the security requirements of personal networks, and develops a number of multi-channel security protocols. With the help of out-of-band channels, especially no-spoofing and no-blocking out-of-band channels, these protocols can bootstrap security in personal networks. In particular, three kinds of security protocols have been studied: protocols that use human-controlled channels, protocols that use visible light communications, and protocols that use intra-body communications. Interesting trade-offs have been discovered among communication, computation and security, resulting from different channel implementations and protocols.
25
Ng, Ping Chung. "Link-directionalities in carrier sense wireless networks". Thesis, University of Oxford, 2008. http://ora.ox.ac.uk/objects/uuid:348ccd31-8996-4536-b6f9-b2513ab26201.
Texto completoResumen
In this thesis, research is described which leads to the proposal of a link-directionality-based dual channel MAC (Medium Access Control) protocol (DCP) for carrier sense wireless ad hoc networks. It attempts to double the capacities of such networks using an industrial standard (the single-channel IEEE 802.11 protocol) as a benchmark. Simulations show that the proposed scheme can increase the capacities to more than 1.7 times of the single-channel IEEE 802.11 protocol in large-scale random network topologies. The algorithm, however, requires extra radio spectrum resource which could be costly. In addition to DCP, a signal-to-interference ratio comparison algorithm (SCA) is proposed to further release the protocol constraints imposed by the virtual carrier-sensing mechanism. Interestingly, while the capacity of the pure DCP decreases when link lengths are short, the capacity of the pure SCA increases when link lengths are short. The two algorithms compensate for the downside of each other to bring about a more uniform capacity improvement. Simulations show that the integrated scheme can further increase the network throughputs to more than 2.13 times in random topologies. This thesis also clarifies inter-link interference in wireless ad-hoc networks by using link-directional interference graphs (l-graph). By colouring the l-graphs, independent data streams obtained by Multi-Carrier Code Division Multiple Access (MC-CDMA) are assigned for transmitting up-link and down-link traffic separately in order to eliminate the hidden-node and exposed-node problems in wireless local area networks (WLAN). Finally, a generic approach for capacity analysis is proposed to show that the concept of link-directionality can also be adopted with other network models, protocols and parameter settings. However, in certain scenarios where links are densely packed together, the advantage of using link-directionality could be diminished. Therefore, the proposed generic approach for capacity analysis allows one to determine whether channel allocations according to link-directionalities should be applied to a given network.
26
Sahebi, Mahmod Reza. "Understanding microwave backscattering of bare soils by using the inversion of surface parameters, neural networks and genetic algorithm". Thèse, Université de Sherbrooke, 2003. http://savoirs.usherbrooke.ca/handle/11143/2736.
Texto completoResumen
Estimates of the physical parameters of the soil surface, namely moisture content and surface roughness, are important for hydrological and agricultural studies, as they appear to be the two major parameters for runoff forecasting in an agricultural watershed. Radar has high potentiality for the remote measurement of soil surface parameters. In particular, the investigation of the radar backscattering response of bare soil surfaces is an important issue in remote sensing because of its capacity for retrieving the desired physical parameters of the surface. The objective of this study is to formulate and to constrain a methodology for solving the inverse problem for the operational retrieval of soil surface roughness and moisture. To separate the effects of the different parameters on the measured signal over complex areas, multi-technique concepts (multi-polarization, multi-angular, multi-sensor, multi-frequency, and multi-temporal) are the main solution. In this work, based on a simulation study, three different configurations, multi-polarization, multi-frequency and multi-angular, are compared to obtain the best configuration for estimating surface parameters and the multi-angular configuration gives the best results. Based on these results, this study was continued according to five different phases: (1) A new index, the NBRI (Normalized radar Backscatter soil Roughness Index), using the multi-angular approach was presented. This index can estimate and classify surface roughness in agricultural fields using two radar images with different incidence angles. (2) A new linear empirical model to estimate soil surface moisture using RADARSAT-1 data was proposed. This model can provide soil moisture with reduced errors of estimation compared to other linear models. (3) Inversion of the surface parameters using nonlinear classical methods. In this case, the Newton-Raphson method, an iterative numerical method, was used in the retrieval algorithm to solve the inverse problem. (4) In this phase, the neural network technique, with a dynamic learning method, was applied to invert the soil surface parameters from the radar data. The results were obtained through performance testing on two different input schemes (one and two data series) and two different databases (theoretical and empirical). The advantage of the multi-angular set with measured data is apparent. These results are the best in this study. (5) Finally, a novel genetic algorithm (GA) was developed to retrieve soil surface parameters. In this study, it is shown that the genetic algorithms, as an optimization technique, can estimate simultaneously soil moisture and surface roughness from only one radar image.
27
Muller, Martinette. "Neural network models of slotted waveguide directional couplers". Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52354.
Texto completoResumen
Thesis (MScEng)--University of Stellenbosch, 2001.ENGLISH ABSTRACT: The application of artificial neural networks to microwave circuits is investigated. A neural network model is developed for two parallel waveguides coupled by a longitudinal slot in the common broad wall. Training data is generated through a moment method solution of the integral equations that describe the structure. A systematic investigation of training options is carried out and the development of the model is described in detail. The model is evaluated and compared with an Adaptive Sampling Interpolation (ASI) Technique. The neural network is found to be less accurate than the ASI Technique at a much greater expense of development time and required user supervision.
AFRIKAANSE OPSOMMING: Die toepassing van neurale netwerke op mikrogolfbane is ondersoek. In Neurale netwerk-model is ontwikkel vir twee parallelle golfleiers met longitudinale gleufkoppeling in die gemeenskaplike bree wand. Data vir die opleiding van die netwerke is verkry deur In momentmetode-oplossing van die integraalvergelykings wat die struktuur beskryf. Verskillende ontwerpsopsies vir die netwerke is stelselmatig ondersoek en die ontwikkelingsproses van die netwerk is volledig beskryf. Die model is geevalueer en vergelyk met In Aanpasbare Monstering Interpolasietegniek (AMI). Daar is gevind dat die neurale netwerk minder akkuraat is as die AMI terwyl die koste aan ontwikkelingstyd en gebruikerstoesig hoer is.
28
Ramezani, Khosrow. "Coordinated Robust Authentication In Wireless Networks". Thesis, Griffith University, 2016. http://hdl.handle.net/10072/367051.
Texto completoResumen
Rapid convergence of heterogeneous wireless communication technologies such as Wireless Local Area Networks (WLAN), 4G: LTE/LTE-Advanced Mobile Broadband, 5G and Worldwide Interoperability for Microwave Access (WiMAX), attract new opportunities for ubiquitous connectivity enabling collaborative usage. Hence, it is predicted that the ever-increasing use of wireless Internet demands a significant increase in wireless broadband throughput. However, to maintain reliable and seamless connectivity wireless devices entail simultaneous multi-gateway connections. Therefore, emerging technologies should be capable of performing secure roaming between the diverse wireless networks. Nevertheless, vertical handover (roaming) and seamless connectivity involve overcoming not only the incompatibility issues between the different wireless technologies but also the incompatibility issues amongst the authentication mechanisms used in the various wireless networks.
For seamless connectivity, wireless devices need to authenticate in a timely fashion with the different types of wireless networks. However, the authentication mechanisms used in these wireless networks can be specific and fitting only to those wireless technologies. Hence, roaming becomes a major challenge due to the incompatible authentication mechanisms, parameters and credentials. Further, users demand a single but unique set of credentials to authenticate the wireless devices in the heterogeneous wireless environment. In other words, future heterogeneous networks demand a coordinated authentication mechanism for vertical handover with the ability to use a single but unique set of credentials enabling secure and fast roaming.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Information and Communication Technology
Science, Environment, Engineering and Technology
Full Text
29
Nassef, M. A. "Computer-aided analysis and design of non-linear and time variant multiport microwave networks using state space techniques with practical applications". Thesis, University of Kent, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375056.
Texto completo
30
Albannay, Mohammed Masoud. "Array of antenna arrays". Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/75576/1/Mohammed_Albannay_Thesis.pdf.
Texto completoResumen
Antenna arrays are groups of antenna elements spaced in a geometrical pattern. By changing the phase excitation of each element, the array is capable of transmitting electromagnetic waves strongly in a chosen direction with little or no radiation in another direction, thus controlling the array's radiation pattern without physically moving any parts. An antenna array of sub-arrays replaces conventional antenna elements with compact circular arrays with potential for improved performance.
This thesis expands on the concept by exploring the development, realisation and operation of an array of subarrays. The overall size of the array essentially remains the same, but the array's performance is improved due to having steerable directive subarrays. The negative effects of strong mutual coupling between closely spaced elements of a subarray are analysed and a number of new solutions for element decoupling are proposed.
31
Ekmekci, Evren. "Design, Fabrication And Characterization Of Novel Metamaterials In Microwave And Terahertz Regions: Multi-band, Frequency-tunable And Miniaturized Structures". Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612730/index.pdf.
Texto completoResumen
This dissertation is focused on the design, fabrication, and characterization of novel metamaterials in microwave and terahertz regions with the following outcomes:
A planar µ-negative metamaterial structure, called double-sided SRR (DSRR), is proposed in the first part of this study. DSRR combines the features of a conventional split ring resonator (SRR) and a broadside-coupled SRR (BC-SRR) to obtain much better miniaturization at microwave frequencies for a given physical cell size. In addition to DSRR, double-sided multiple SRR (DMSRR), double-sided spiral resonator (DSR), and double-sided U-spiral resonator (DUSR) have been shown to provide smaller electrical sizes than their single-sided versions under magnetic excitation. In the second part of this dissertation, a novel multi-band tunable metamaterial topology, called micro-split SRR (MSSRR), is proposed. In addition to that, a novel magnetic resonator structure named single loop resonator (SLR) is suggested to provide two separate magnetic resonance frequencies in addition to an electric resonance in microwave region. In the third part, two different frequency tunable metamaterial topologies called BC-SRR and gap-to-gap SRR are designed, fabricated and characterized at terahertz frequencies with electrical excitation for the first time. In those designs, frequency tuning based on variations in near field coupling is obtained by in-plane horizontal or vertical displacements of the two SRR layers. The values of frequency shifts obtained for these tunable metamaterial structures are reported to be the highest values obtained in literature so far. Finally, in the last part of this dissertation, novel double-sided metamaterial based sensor topologies are suggested and their feasibility studies are presented.
32
Mustafa, Haithem A. "Opto-VLSI-based adaptive optical power splitter/combiner for next generation dynamic optical telecommunication networks". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2013. https://ro.ecu.edu.au/theses/923.
Texto completoResumen
The demand for optical power splitters is growing globally, due to the rapid deployment of fibre-to-the-premises, optical metropolitan area network (MAN), and active optical cables for TV/Video signal transport. Optical splitters play an important role in passive optical network (PON) technology by enabling several hundred users to share one optical line terminal. However, current PONs, which use fixed optical power splitters, have limited reconfigurability particularly in adding/dropping users to/from an optical network unit.
An adaptive optical power splitter (OPS) can dynamically reallocate the opticalpower in the entire network according to the real-time distribution of users and services, thus providing numerous advantages such as improve an optical network efficiency, scalability, and reliability. An adaptive OPS is also important for realizing self-healing ring-to-ring optical MAN, thus offering automatic communication recovery when line break occurs. In addition, future optical line protection systems will require adaptive optical splitters to switch optical signals from faulty lines to active power lines, avoid the use of optical attenuators and/or amplifiers, and achieve real time line monitoring. An adaptive OPS can also be incorporated in tunable optical dispersion compensators, optical attenuator and optical gain equalizer, and reconfigurable optical switches.
This thesis proposes and demonstrates the principle of a novel Opto-VLSI-based adaptive optical splitter/combiner for next generation dynamic optical telecommunication networks. The proposed splitter structure enables an input optical power to be split adaptively into a larger number of output fibre ports, through optimized phase holograms driving the Opto-VLSI processor. The new adaptive optical splitter has additional advantages including lossless operation, adequate inter-port crosstalk, compressed hardware and simple user interface.
This thesis demonstrates, in particular, the concept of an adaptive optical power splitter employing an Opto-VLSI processor and a 4-f imaging system experimentally in three stages as follow: (i) a 1×2 adaptive optical power splitter based on an Opto-VLSI processor, a fibre collimator array and 4-f imaging systems (single lens), (ii) a 1×4 adaptive optical power splitter based on an Opto-VLSI processor, a fibre array and 4-f imaging systems (single lens), and (iii) a 1×N lossless adaptive optical power splitter structure integrating an Opto-VLSI processor, optical amplifiers, a fibre array, and an array of 4-f imaging systems (lens array). The thesis also demonstrates the concept of an adaptive optical signal combiner which enables multiple signals to be combined with user-defined weight profiles into a single fibre port.
Experimental results demonstrate that an input optical signal can arbitrarily be split into N signals and coupled into optical fibre ports by uploading optimized multicasting phase holograms onto the Opto-VLSI processor. They also demonstrate that N input optical signals can be dynamically combined with arbitrary weights into a single optical fibre port. Excellent agreement between theoretical and experimental results is demonstrated. The total insertion loss of the optical power splitter is only 5 dB. Results also show that the optical amplifiers can compensate for the insertion and splitting losses, thus enabling lossless splitter operation. A crosstalk level around -25 dB and a wavelength spectral range exceeding 40 nm is experimentally realized.
In addition, a novel broadband adaptive RF power splitter/combiner based on Opto-VLSI processor is proposed and experimentally demonstrated. By uploading optimized multicasting phase holograms onto the software-driven Opto-VLSI processor, the input RF signal is dynamically split and directed to different output ports, with userdefined splitting ratios. Also, multiple input RF signals can be dynamically combined with arbitrary user-defined weights. As a proof-of-concept demonstration, two input RF signals are dynamically combined with different user-defined weight profiles.
We also propose and demonstrate a photonic microwave filter based on the use of an Opto-VLSI-based adaptive optical combiner. The experimental results demonstrate that the developed Opto-VLSI-based adaptive optical combiner can dynamically route multiple input optical signals to a single output, with user-defined weight profiles, thus realising a tunable microwave filter.
Overall this Opto-VLSI-based adaptive optical power splitter should allow as many as 32 output ports to be supported while achieving high splitting resolution and dynamic range. This will greatly enhance the efficiency of optical communication networks.
33
Zamorovskii, Vlad. "Composite materials filled with ferromagnetic microwire inclusions demonstrating microwave response to temperature and tensile stress". Thesis, University of Plymouth, 2017. http://hdl.handle.net/10026.1/9488.
Texto completoResumen
Amorphous and polycrystalline microwires cast from ferromagnetic Fe-based or Co-based alloys in glass envelope demonstrate unique magneto-anisotropic and high frequency impedance properties that make them very attractive for sensor applications. Magnetic anisotropies of different types result from the inverse magnetostriction effect (positive or negative) at the interface between the glass shell and the metal core, in the presence of the residual stresses induced during the Taylor-Ulitovski casting method. Therefore, the glass shell is not just isolation, but also is one of most important factors that defines the physical properties of microwires. In particular, magnetic anisotropy allows high frequency impedance to be tuned by external stimuli such as magnetic field, tensile stress, or temperature. In the project, these effects are explored for the creation of low density microwire inclusions that might introduce tuneable microwave properties to polymer composite materials. The project aims to study high frequency impedance effects in ferromagnetic wires in the presence of tensile stress, temperature, and magnetic field. The integration of microwave equipment with mechanical and thermal measurement facilities is a very challenging task. In the project, we develop new experimental techniques allowing comprehensive study of composite materials with electromagnetic functionalities. The wire surface impedance recovered from such measurements can then be used to model the microwave response from wire-filled composites in free space. The obtained results significantly expand the horizon of potential applications of ferromagnetic wires for structural health monitoring.
34
Walton, Robert. "A microwave Nonlinear Network Analyser". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0016/MQ55268.pdf.
Texto completo
35
Mogk, Nathan William. "Microwave-Powered Wireless Sensor Network". Thesis, The University of Arizona, 2012. http://hdl.handle.net/10150/244493.
Texto completoResumen
This thesis describes the design and construction of a wireless sensor network that harvests power for operations from a rectifying antenna. This project represents a proof-of-concept for future systems that will someday operate without the need of batteries or other conventional methods of storing power. This project was completed as a senior design project in the Engineering program at The University of Arizona for Drs. Marcellin and Xin. This project developed the described system from concept to an operational test in the laboratory that demonstrated the system working as expected while being powered by wireless energy transmission. Node input voltage reached a steady state near 0.8 V, and remained so for the entirety of the test. This project was pursued as a group effort.
36
Silva, Patric Lacouth da. "Modelagem de Superf?cies Seletivas de Freq??ncia e Antenas de Microfita utilizando Redes Neurais Artificiais". Universidade Federal do Rio Grande do Norte, 2006. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15517.
Texto completoResumen
Made available in DSpace on 2014-12-17T14:56:21Z (GMT). No. of bitstreams: 1
PatricLS.pdf: 758253 bytes, checksum: 5014311c01c22242625c739abbfdc673 (MD5)
Previous issue date: 2006-06-09Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
This work has as main objective the application of Artificial Neural Networks, ANN, in the resolution of problems of RF /microwaves devices, as for example the prediction of the frequency response of some structures in an interest region. Artificial Neural Networks, are presently a alternative to the current methods of analysis of microwaves structures. Therefore they are capable to learn, and the more important to generalize the acquired knowledge, from any type of available data, keeping the precision of the original technique and adding the low computational cost of the neural models. For this reason, artificial neural networks are being increasily used for modeling microwaves devices. Multilayer Perceptron and Radial Base Functions models are used in this work. The advantages/disadvantages of these models and the referring algorithms of training of each one are described. Microwave planar devices, as Frequency Selective Surfaces and microstrip antennas, are in evidence due the increasing necessities of filtering and separation of eletromagnetic waves and the miniaturization of RF devices. Therefore, it is of fundamental importance the study of the structural parameters of these devices in a fast and accurate way. The presented results, show to the capacities of the neural techniques for modeling both Frequency Selective Surfaces and antennas
Este trabalho tem como principal objetivo a aplica??o de Redes Neurais Artificiais, RNA, na resolu??o de problemas de dispositivos de RF /microondas, como por exemplo a predi??o da resposta em freq??ncia de algumas estruturas em uma regi?o de interesse. As Redes Neurais Artificiais se apresentam como uma alternativa aos m?todos atuais de an?lise de estrutura de microondas, pois s?o capazes de aprender, e o mais importante generalizar o conhecimento adquirido, a partir de qualquer tipo de dado dispon?vel, mantendo a precis?o da t?cnica original utilizada e aliando o baixo custo computacional dos modelos neurais. Por esse motivo, as redes neurais artificiais s?o cada vez mais utilizadas para a modelagem de dispositivos de microondas. S?o utilizados neste trabalho os modelos Perceptron de M?ltiplas Camadas e de Fun??es de Base Radiais. S?o descritas as vantagens/desvantagens de cada um desses modelos, assim como os algoritmos de treinamento referentes a cada um deles. Dispositivos planares de microondas, como Superf?cies Seletivas de Freq??ncias e as antenas de microfita, ganham cada vez mais destaque devido ?s necessidades crescentes de filtragem e separa??o de ondas eletromag?ticas e ? miniaturiza??o de dispositivos de R?dio-Freq??ncia. Por isso ? de import?ncia fundamental o estudo dos par?metros estruturais desses dispositivos de forma r?pida e precisa. Os resultados apresentados, demonstram as capacidades das t?cnicas neurais para modelagem de Superf?cies Seletivas de Freq??ncia e antenas
37
Laias, Elmabruk M. "Performance Analysis and Enhancement of QoS Framework for Fixed WiMAX Networks. Design, analysis and evaluation of 802.16 Point-to-Multipoint (PMP) Quality of Service Framework based on uplink scheduler and call admission control analysis". Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4318.
Texto completoResumen
Given the current developments and advances in the scientific and technological aspects of human knowledge and introducing new approaches in various fields of telecommunication technologies and industries, there has been an increasing growth in its players' plans and a positive change in their outlooks in order to achieve the target of "anywhere and anytime access". Recent developments of WiMAX (Worldwide interoperability for Microwave Access) networks, as a sign of increasing needs and demands for new telecommunication services and capabilities, have led to revolutions in global telecommunication which should be perceived properly in terms of the commercial and technical aspects in order to enjoy the new opportunities. Most experts believe that WiMAX technology is a preliminary step to develop Fourth Generation networks known as 4G technologies. It has not only succeeded in the utilization of several of the latest telecommunication techniques in the form of unique practical standards, but also paved the way for the quantitative and qualitative developments of high-speed broadband access. IEEE 802.16 Standard introduces several advantages, and one of them is the support for Quality of Services (QoS) at the Media Access Control (MAC) level. For these purposes, the standard defines several scheduling classes at MAC layer to treat service flow in a different way, depending on QoS requirements. In this thesis, we have proposed a new QoS framework for Point-to-Multi Point (PMP) 802.16 systems operating in Time Division Duplexing (TDD) mode over a WirelessMAN-OFDM physical layer. The proposed framework consists of a Call Admission Control (CAC) module and a scheduling scheme for the uplink traffic as well as a simple frame allocation scheme. The proposed CAC module interacts with the uplink scheduler status and it makes its decision based on the scheduler queue status; on the other hand, the proposed scheduling scheme for the uplink traffic aims to support realtime flows and adapts the frame-by-frame allocations to the current needs of the connections, with respect to the grants boundaries fixed by the CAC module. Extensive OPNET simulation demonstrates the effectiveness of the proposed architecture.
38
Passos, Marcio Galdino. "Modelos de dispositivos de microondas e ?pticos atrav?s de redes neurais artificiais de alimenta??o direta". Universidade Federal do Rio Grande do Norte, 2006. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15392.
Texto completoResumen
Made available in DSpace on 2014-12-17T14:55:56Z (GMT). No. of bitstreams: 1
MarcioGP.pdf: 1534925 bytes, checksum: d1c777b1e76b23d509caeb3258a0aa97 (MD5)
Previous issue date: 2006-06-19This dissertation contributes for the development of methodologies through feed forward artificial neural networks for microwave and optical devices modeling. A bibliographical revision on the applications of neuro-computational techniques in the areas of microwave/optical engineering was carried through. Characteristics of networks MLP, RBF and SFNN, as well as the strategies of supervised learning had been presented. Adjustment expressions of the networks free parameters above cited had been deduced from the gradient method. Conventional method EM-ANN was applied in the modeling of microwave passive devices and optical amplifiers. For this, they had been proposals modular configurations based in networks SFNN and RBF/MLP objectifying a bigger capacity of models generalization. As for the training of the used networks, the Rprop algorithm was applied. All the algorithms used in the attainment of the models of this dissertation had been implemented in Matlab
Esta disserta??o contribui para o desenvolvimento de metodologias atrav?s de redes neurais artificiais de alimenta??o direta para a modelagem de dispositivos de microondas e ?pticos. Uma revis?o bibliogr?fica sobre as aplica??es de t?cnicas neuro-computacionais na ?reas de engenharia de microondas e ?ptica foi realizada. As caracter?sticas das redes MLP, RBF e SFNN, bem como as estrat?gias de aprendizado supervisionado foram apresentadas. As express?es de ajuste dos par?metros livres das redes acima citadas foram deduzidas a partir do m?todo do gradiente. O m?todo convencional EM-ANN foi aplicado na modelagem de dispositivos passivos de microondas e amplificadores ?pticos. Para isto, foram propostas configura??es modulares baseadas em redes SFNN e RBF/MLP objetivando uma maior capacidade de generaliza??o dos modelos. No que se refere ao treinamento das redes utilizadas, o algoritmo Rprop foi aplicado. Todos os algoritmos utilizados na obten??o dos modelos desta disserta??o foram implementados em Matlab
39
El-Sawi, Yehia Ali Reda Ali. "Parallel processing application to nonlinear microwave network design". Thesis, University of Kent, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257300.
Texto completo
40
Adams, Emily, Ayman Albagshi, Khaleel Alnatar, Gregory Jacob, Nathan Mogk y Alexis Sparrold. "A Wireless Sensor Network Powered by Microwave Energy". International Foundation for Telemetering, 2012. http://hdl.handle.net/10150/581655.
Texto completoResumen
ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, CaliforniaSystems that monitor environments often rely on cumbersome wires to supply power to the sensing equipment or batteries that require monitoring and replacement. As technologies continue to advance, the use of self-sustaining, wireless powering becomes more essential to satisfy challenging requirements that necessitate continuous measurement and general functionality. This paper focuses on the creation of a wireless sensor network with emphasis on the implementation of wirelessly charged sensing nodes by utilizing microwaves. Three subsystems make up this "proof of concept" wireless sensor system: a power transmitting base station, three sensor nodes, and a communication base station. Interfacing and power regulation are of the utmost importance in order to ensure all of the subsystems are able to communicate with one another and power all necessary functions. The power transmitting base station transmits microwaves to the nodes. A rectenna on each node converts the transmitted microwaves into DC power. Each node contains sensors to monitor the temperature and light of the environment. For the communication aspect of the system, Zigbee protocol, which belongs to IEEE 802.15.4 protocol, is used fore wireless communication between the base station and the nodes. Through the combination of power regulation, microwave energy, and radio transmission, users are able to utilize this system to collect environmental sensor data wirelessly.
41
Luff, G. F. "A real-time microwave network analyser using multiport techniques". Thesis, University of Cambridge, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372887.
Texto completo
42
Wright, Andrew Simon. "A biphase-bimodulation dual six-port microwave network analyser". Thesis, University of Hull, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.333898.
Texto completo
43
Walma, Mathys. "Multiple access schemes for the Microwave Light Organized Network (MILTON)". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0019/MQ52395.pdf.
Texto completo
44
Peronnin, Théau. "Building and operating a quantum node of a microwave network". Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEN025.
Texto completoResumen
Après des années de développement académique, l’électrodynamique quantique en circuit entre dans l’ère des applications. Cette thèse a été réalisée dans une volonté de créer des outils pour faire le lien entre une curiosité académique quantique, les circuits supraconducteurs, et un objectif majeur, l’ordinateur quantique universel. Une architecture vraisemblable de processeur quantique consiste à connecter en réseau un grand nombre de modules élémentaires. Lors de cette thèse expérimentale, le noeud d’un tel réseau, le quantum node, a été développé et fabriqué grâce aux techniques de l’état de l’art des circuits imprimés quantiques microonde. Ce circuit a été utilisé pour réaliser pour la première fois une méthode de lecture séquentielle d’un qubit supraconducteur. Cette méthode, proposée en 2013 par Sete et al., permettrait une lecture plus rapide et plus précise des qubits supraconducteurs. La lecture des qubits est l’un des obstacles majeurs limitant le développement d’ordinateurs quantiques universels sans erreur, ce qui rend ce projet autant intéressant pour sa mise en oeuvre inédite du quantum node que pour ses applications. Cette nouvelle méthode de lecture atteint des performances proches de l’état de l’art alors même que le circuit n’était pas optimisé pour cette fin. Lors de cette thèse, nous avons aussi contribué à deux autres expériences d’optique quantique microonde, détaillées ici. Un circuit dédié a été développé pour démontrer une nouvelle forme de mesure quantique : la mesure multiplexée du nombre de photons. Dans cette expérience, menée par A. Essig et Q. Ficheux, un qubit supraconducteur est lu simultanément à plusieurs fréquences pour extraire plus d’un bit d’information à la fois à propos du nombre de photons contenus dans un résonateur microonde couplé à un qubit. Enfin, nous avons contribué à la démonstration expérimentale de la suppression exponentielle des bit-flips dans un qubit encodé dans un état de chat de Schrödinger d’un mode microonde. Cette expérience, menée par R. Lescanne et Z. Leghtas, démontre une augmentation par un facteur 300 du temps de vie du qubit grâce à la correction d’erreur quantique autonome réalisée grâce à l’ingénierie de la dissipation d’un mode microondeAfter years of academic development, the circuit quantum electrodynamics is entering the age of applications. This thesis was realized in this context of creating tools to bridge the gap between an astounding academic quantum system, superconducting circuits, and a grand goal, the universal quantum computer. A likely blueprint for quantum processors consists in the assembly of a large number of elementary modules arranged in a network.In this experimental thesis, a possible node for such a network, the quantum node, was developed and fabricated using state-of-the-art techniques for 2D superconducting microwave circuits. This node was first used to implement a novel sequential readout method for a superconducting qubit. This experiment, first proposed in 2013 by Sete et al., potentially allows for faster, more accurate read out of superconducting qubits. The read out of qubits is one of the several bottlenecks limiting the development of fault-tolerant superconducting quantum computers, which made this project both useful as a demonstration of the quantum node and for applications. This novel readout method achieves readout performances close to state-of-the-art of superconducting qubit readout even though the chip was not optimized for that purpose.During this work, we also contributed to two other experiments engineering quantum measurement and dissipation with superconducting circuits. First, a dedicated circuit was developed to demonstrate a new form of quantum measurement: the multiplexed photon number measurement. In that experiment led by A. Essig and Q. Ficheux, a superconducting transmon quantum bit is read out at multiple frequencies simultaneously to extract more than one bit of information about the number of photons contained in a microwave resonator coupled to that quantum bit.Second, we contributed to the experimental demonstration of the exponential suppression of bit-flips in a qubit encoded in a Schrödinger Cat state of a microwave mode. This experiment led by R. Lescanne and Z. Leghtas, demonstrates the improvement by a factor 300 of the lifetime of a qubit thanks to the autonomous error correction realized through the engineering of the dissipation of a microwave mode
45
Walma, Mathys Carleton University Dissertation Engineering Systems and Computer. "Multiple access schemes for the microwave light organized network (MILTON)". Ottawa, 2000.
Buscar texto completo
46
Svoboda, Jan. "Bezdrátové spoje pro metropolitní sítě". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219290.
Texto completoResumen
This Master’s thesis analizes technologies suitable for metropolitan area networks. In this thesis there are mentioned technologies used for wireless transfer with speeds above 1 Gbps. There are described basic features and parameters of microwave radio relay links in 70/80GHz range and free space optic links. These technologies are compared with classic optical networks. Practical part of thesis was focused on development of application which calculates signal attenuation caused by the passage of the atmosphere for both technologies. Results gained from this application are mentioned in this Master’s thesis.
47
Bozkurt, Ismail. "Theory And Design Of Microwave Fet Frequency Triplers". Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/2/12609918/index.pdf.
Texto completoResumen
Microwave frequency multipliers are very useful and advantageous components in microwave systems, especially, where the generation of high frequency sinusoidal signals is very difficult because of degrading performance of the solid state oscillators with increasing frequency. These components are frequently employed in diverse applications such as commercial wireless communication systems, microwave transmitters and receivers, and military systems. In the following work the basic principles of microwave FET frequency multipliers, specifically concentrated on triplers, are studied presenting theoretical concept and utilizing computerized simulation of piecewise linear FET (PLF) model. The use of PLF model which neglects nonlinear reactances and relies on resistive nonlinearities allows for the theoretical concept and, consequently, the multiplication mechanism in a frequency multiplier to be clearly and easily identified. At the end of this study, after presenting basic considerations on FET frequency multipliers a practical microwave frequency tripler design is presented.
48
Ghorbani, a. "Cross polar cancellation in satellite microwave systems : New practical designs and applications of propagation theory". Thesis, University of Bradford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376711.
Texto completo
49
Altrabsheh, Bilal. "Investigation of low cost techniques for realising microwave and millimeter-wave network analysers". Thesis, University of Surrey, 2003. http://epubs.surrey.ac.uk/843309/.
Texto completoResumen
The work presented in this thesis is on the development of reliable low cost measurement systems for measuring microwave and millimetre-wave devices. The purpose of this work is to find techniques which use multiple power detectors and can measure magnitude and phase without the need for expensive superheterodyne receivers. Two novel microwave measurement systems have been designed with the intention of providing a measurement facility which enables the characterisation of both active and passive devices in terms of their scattering parameters. The first method is based on using a multistate reflectometer, which uses dielectric waveguide in the frequency range of 110GHz up to 170GHz. The dielectric multistate reflectometer is a four-port reflectometer, which uses a programmable phase shifter to give a flat relative phase shift over the entire frequency range of the dielectric waveguides used in the multistate reflectometer. The phase shifter has an eccentric rotating cylinder with an offset axis to allow a number of different phase shifts to the wave travelling in the dielectric waveguides in the multistate reflectometer. This system has been developed as an equivalent to a one-port network analyser. The second method is based on using the multi-probe reflectometer in which the standing wave in a line is measured using a number of fixed detector probes. A microstrip line prototype in the frequency range of 1GHz to 5.5GHz has been demonstrated and the design of a monolithic microwave integrated circuit (MMIC) version for the frequency range of 40GHz to 325GHz has been earned out. Improved methods of calibration of the system have been derived as well as different methods for error correction. The realisation of a full two-port network analyser using the technique has been demonstrated. Key words: dielectric multistate reflectometer, programmable phase shifter, multi-probe reflectometer, detection, microwave measurement, millimetre-wave measurement, calibration, error corrections.
50
Chai, Soo See. "An artificial neural network approach for soil moisture retrieval using passive microwave data". Thesis, Curtin University, 2010. http://hdl.handle.net/20.500.11937/1416.
Texto completoResumen
Soil moisture is a key variable that defines land surface-atmosphere (boundary layer) interactions, by contributing directly to the surface energy and water balance. Soil moisture values derived from remote sensing platforms only accounts for the near surface soil layers, generally the top 5cm. Passive microwave data at L-band (1.4 GHz, 21cm wavelength) measurements are shown to be a very effective observation for surface soil moisture retrieval. The first space-borne L-band mission dedicated to observing soil moisture, the European Space Agency's (ESA) Soil Moisture and Ocean Salinity (SMOS) mission, was launched on 2nd November 2009.Artificial Neural Network (ANN) methods have been used to empirically ascertain the complex statistical relationship between soil moisture and brightness temperature in the presence of vegetation cover. The current problem faced by this method is its inability to predict soil moisture values that are 'out-of-range' of the training data.In this research, an optimization model is developed for the Backpropagation Neural Network model. This optimization model utilizes the combination of the mean and standard deviation of the soil moisture values, together with the prediction process at different pre-determined, equal size regions to cope with the spatial and temporal variation of soil moisture values. This optimized model coupled with an ANN of optimum architecture, in terms of inputs and the number of neurons in the hidden layers, is developed to predict scale-to-scale and downscaling of soil moisture values. The dependency on the accuracy of the mean and standard deviation values of soil moisture data is also studied in this research by simulating the soil moisture values using a multiple regression model. This model obtains very encouraging results for these research problems.The data used to develop and evaluate the model in this research has been obtained from the National Airborne Field Experiments in 2005.