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Bemani, Ali. "Affine Frequency Division Multiplexing (AFDM) for Wireless Communications". Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS610.pdf.
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La recherche de nouvelles formes d'onde robustes, lorsque utilisées sur des canaux doublement sélectifs, est primordiale. De telles formes d'onde permettraient donc d'assurer des communications fiables pour les réseaux sans fil de nouvelle génération dans les scénarios de haute mobilité. Dans cette thèse, une nouvelle solution, le affine frequency division multiplexing (AFDM), est proposée. Cette nouvelle forme d'onde de type multichirps est basée sur la transformée de Fourier affine discrète (DAFT), une variante de la transformée de Fourier discrète caractérisée par deux paramètres pouvant être adaptés pour mieux faire face aux canaux doublement dispersifs. Cette thèse offre une enquête complète sur les principes de l'AFDM au sein des communications à haute mobilité. Elle fournit un aperçu de la relation explicite entrée-sortie dans le domaine DAFT, révélant l'impact conséquent des paramètres de l'AFDM. Le manuscrit détaille le réglage précis des paramètres DAFT qui permette d'assurer une représentation complète délai-Doppler du canal de propagation sans fil. À travers des démonstrations analytiques, il est affirmé que l'AFDM atteint de manière optimale l'ordre de diversité des canaux doublement dispersifs en raison de la représentation complète délai-Doppler du canal qu'il permet d'obtenir. La thèse propose également deux algorithmes de détection à faible complexité pour l'AFDM, tirant parti de la parcimonie inhérente du canal. Le premier est un détecteur de type minimum mean squared error (MMSE) à faible complexité basé sur la factorisation LDL. Le deuxième est un égaliseur de type decision feedback equalizer (DFE) à faible complexité basé sur la combinaison cohérente, grace à la méthode maximum ratio combining (MRC), de différentes copies des symboles d'entrée du canal ayant été altérés par différents trajets de ce dernier. De plus, la thèse présente une technique de type embedded d'estimation de canal pour les systèmes AFDM, exploitant la capacité de l'AFDM à obtenir une représentation complète délai-Doppler du canal. Dans cette approche, un seul symbole pilote est inséré dans le domain DAFT du symbole AFDM, et les interférences que ce pilote pourrait générer pour les symboles de donnée sont évitées par des intervalles de garde. Un algorithme pratique d'estimation de canal, compatible avec ce schéma de transmission de pilote et basé sur une approche de type approximate maximum likelihood (ML), est aussi proposé. La thèse est conclue en se penchant sur de possibles applications de l'AFDM au delà de celles conçues pour les environnements marqués par une haute mobilité, spécifiquement les applications de type integrated sensing and communication (ISAC) et les communications dans les bandes de hautes fréquences. Il est démontré que pour identifier tous les composants de délai et de Doppler liés au milieu de propagation, on peut utiliser soit le signal AFDM complet, soit seulement sa partie pilote constituée d'un symbole de domaine DAFT et de son intervalle de garde. De plus, la nature chirp de l'AFDM permet une annulation simple de l'auto-interférence, éliminant ainsi le besoin de méthodes coûteuses normalement nécessaires dans les systèmes full duplex. La thèse met également en évidence les bonnes performances de l'AFDM pour les communications sans fil dans les bandes de hautes fréquences sans ou avec mobilité, grâce à la répartition maximale du signal AFDM en temps et en fréquences, assurant un gain de couverture. Contrairement à d'autres formes d'onde, l'AFDM ne fournit pas seulement une répartition maximale temps-fréquences mais assure également une détection robuste et efficace et une résilience au décalage de fréquence de porteuse et au bruit de phaseIn the realm of next-generation wireless systems (beyond 5G/6G), the vision is clear: to support a broad range of services and applications. This includes ensuring reliable communications in environments marked by high mobility, such as high-speed railway systems and various vehicular communications. Despite the deployment of various multicarrier techniques like orthogonal frequency division multiplexing (OFDM) and single-carrier frequency division multiple access (SC-FDMA) in standardized communication systems, the challenge persists. These techniques, while effective in time-invariant frequency selective channels, face performance degradation in high mobility scenarios due to the destruction of orthogonality among subcarriers caused by significant Doppler frequency shifts. Addressing this, the search for new, robust modulation techniques is paramount. It stands as a key area of investigation aiming to resolve the reliable communications issue for next-generation wireless networks within doubly-selective wireless channels. In this thesis, a novel solution, affine frequency division multiplexing (AFDM), is proposed. This new chirp-based multicarrier waveform is based on the discrete affine Fourier transform (DAFT), a variant of the discrete Fourier transform characterized with two parameters that can be adapted to better cope with doubly dispersive channels. This thesis provides a comprehensive investigation into the principles of AFDM within high mobility communications. It provides insight into the explicit input-output relation in the DAFT domain, unveiling the consequential impact of AFDM parameters. The manuscript details the precise setting of DAFT parameters, ensuring a full delay-Doppler representation of the channel. Through analytical demonstrations, it asserts that AFDM optimally achieves the diversity order in doubly dispersive channels due to its full delay-Doppler representation. The thesis also proposes two low-complexity detection algorithms for AFDM, taking advantage of its inherent channel sparsity. The first is a low complexity MMSE detector based on LDL factorization. The second is a low complexity iterative decision feedback equalizer (DFE) based on weighted maximal ratio combining (MRC) of the channel impaired input symbols received from different paths. Additionally, the thesis presents an embedded channel estimation strategy for AFDM systems, leveraging AFDM's ability to achieve full delay-Doppler representation of the channel. In this approach, an AFDM frame contains a pilot symbol and data symbols, with zero-padded symbols employed as guard intervals to prevent interference. A practical channel estimation algorithm based on an approximate maximum likelihood (ML) approach and compatible with this pilot scheme is also provided. The thesis concludes by delving into the expanded applications of AFDM, specifically in integrated sensing and communication (ISAC) and extremely high frequency (EHF) band communications. It is demonstrated that to identify all delay and Doppler components linked with the propagation medium, one can use either the full AFDM signal or only its pilot part consisting of one DAFT domain symbol and its guard interval. Furthermore, the chirp nature of AFDM allows for unique and simple self-interference cancellation with a single pilot, eliminating the need for costly full-duplex methods. The thesis also highlights AFDM's efficient performance in high-frequency bands (with or without mobility), where the maximal spreading of its signal in time and frequency ensures a coverage gain. Unlike other waveforms, AFDM not only provides maximal time-frequency spreading but also ensures robust and efficient detection, characterized by one-tap equalization and resilience to carrier frequency offset (CFO) and phase noise
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Theurer, Michael Andreas Davy [Verfasser], Martin [Akademischer Betreuer] Schell, Martin [Gutachter] Schell e Frank [Gutachter] Peters. "Electroabsorption modulated lasers and hybridly integrated lasers for communication and sensing / Michael Andreas Davy Theurer ; Gutachter: Martin Schell, Frank Peters ; Betreuer: Martin Schell". Berlin : Technische Universität Berlin, 2021. http://d-nb.info/1238141013/34.
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Cook, Benjamin Stassen. "Vertical integration of inkjet-printed RF circuits and systems (VIPRE) for wireless sensing and inter/intra-chip communication applications". Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/51844.
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Inkjet-printing is a technology which has for the last decade been exploited to fabricate flexible RF components such as antennas and planar circuit elements. However, the limitations of feature size and single layer fabrication prevented the demonstration of compact, and high efficiency RF components operating above 10 GHz into the mm-Wave regime which is critical to silicon integration and fully-printed modules. To overcome these limitations, a novel vertically-integrated fully inkjet-printed process has been developed and characterized up to the mm-Wave regime which incorporates up to five highly conductive metal layers, variable thickness dielectric layers ranging from 200 nm to 200 um, and low resistance through-layer via interconnects. This vertically-integrated inkjet printed electronics process, tagged VIPRE, is a first of its kind, and is utilized to demonstrate fully additive RF capacitors, inductors, antennas, and RF sensors operating up to 40 GHz. In this work, the first-ever fully inkjet printed multi-layer RF devices operating up to 40 GHz with high-performance are demonstrated, along with a demonstration of the processing techniques which have enabled the printing of multi-layer RF structures with multiple metal layers, and dielectric layers which are orders of magnitude thicker than previoulsy demonstrated inkjet-printed structures. The results of this work show the new possibilities in utilizing inkjet printing for the post-processing of high-efficiency RF inductors, capacitors, and antennas and antenna arrays on top of silicon to reduce chip area requirements, and for the production of entirely printed wireless modules.
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Dandin, Marc Péralte. "Towards integrated fluorescence sensing". College Park, Md.: University of Maryland, 2007. http://hdl.handle.net/1903/7811.
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Thesis (M.S.) -- University of Maryland, College Park, 2007.Thesis research directed by: Dept. of Electrical and Computer Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Ayerra, Raquel, Manuel Jimenez e Asier Vega. "Integrated Marketing Communications in Advertising". Thesis, Halmstad University, School of Business and Engineering (SET), 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-852.
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This research is made with the aim of find out how Iberostar communicates its values through Offline and Online advertising campaigns and if those campaigns send the same message to the target audience
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Сагер, Людмила Юріївна, Людмила Юрьевна Сагер, Liudmyla Yuriivna Saher, Алла Миколаївна Дядечко, Алла Николаевна Дядечко e Alla Mykolaivna Diadechko. "Integrated marketing communications: theoretical bases". Thesis, Видавництво СумДУ, 2010. http://essuir.sumdu.edu.ua/handle/123456789/16300.
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Kunzelman, Jill Nicole. "Polymers with Integrated Sensing Capabilities". Cleveland, Ohio : Case Western Reserve University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=case1238086140.
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Soltanalian, Mojtaba. "Signal Design for Active Sensing and Communications". Doctoral thesis, Uppsala universitet, Avdelningen för systemteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-230655.
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Man-made active sensing systems such as active radar and sonar have been a vital part of our civilization's advancement in navigation, defense, meteorology, and space exploration. Modern active sensing systems rely heavily on the significant progress in the science and technology of communications made within the last century. Not surprising, the fast growing communications technology has changed each and every aspect of our everyday lives. This thesis is concerned with signal design for improving the performance of active sensing and communication systems: The target detection and estimation performance of the active sensing systems can be considerably improved by a judicious design of the probing signals. Similarly, signal design has a crucial role in the implementation and efficiency of communication systems. Signal optimization for active sensing and communications usually deals with various measures of quality. This thesis focuses on several quality measures including (i) correlation and spectral metrics, (ii) signal-to-noise ratio (SNR) and mean-square error (MSE) performance metrics, (iii) information-theoretic criteria, (iv) sparsity-related metrics, and (v) beam-pattern matching metrics. The associated problems are studied and several novel algorithms are proposed to tackle the generally difficult arising problems.
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Lith, Joris van. "Novel integrated optical sensing platforms for chemical and immuno-sensing". Enschede : University of Twente [Host], 2005. http://doc.utwente.nl/58010.
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Randell, Damian P. "Integrated antenna diplexer for mobile communications". Thesis, University of Birmingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402528.
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The rapid growth in second generation mobile telecommunications has resulted in the design of the third generation mobile telecommunication system together with proposals for the fourth generation system. Much of this has been driven by consumer requirements for a global telecommunications system, allowing connection from anywhere around the world and offering data rates that facilitate access to a range of multimedia services. Therefore, continual research into mobile handsets, improving standards and delivering smaller, lower cost devices, is required. The work presented reviews the different mobile technologies and highlights trends in design and application, presenting research into new configurations of RF front-end systems and antennas for mobile communications, specifically the third generation mobile telecommunication system. Developments in the integration of digital circuits has dramatically reduced handset sizes in recent years. However, the same progress has not been seen within RF circuitry. This work, therefore, investigates the properties of microstrip patch antennas for use within mobile handsets and the development of an integrated diplexer antenna. Having reviewed microstrip filters, further designs for a diplexer are also presented. The limitations of these designs are investigated and solutions proposed.
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Mao, Chunxu. "Integrated filtering antennas for wireless communications". Thesis, University of Kent, 2017. https://kar.kent.ac.uk/69475/.
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In traditional radio frequency (RF) front-end subsystems, the passive components, such as antennas, filters, power dividers and duplexers, are separately designed and cascaded via the 50 Ω interfaces. This traditional approach results in a bulky and heavy RF front-end subsystem, and suffers from compromised efficiency due to the losses in the interconnections and the mismatching problems between different components. The frequency responses of the antennas such as the frequency selectivity and bandwidth are usually degraded, especially for microstrip antennas. To improve the frequency responses and reduce the size of RF front ends, it is important to investigate novel highly integrated antennas which exhibit multiple functions such as radiation, filtering, power dividing and combining or duplexing, simultaneously. In this thesis, several innovative designs of compact, multi-functional integrated an-tennas/arrays are proposed for wireless communication applications. First, new methods of designing integrated filtering antenna elements with broadband or dual-band performance are investigated. These antennas also feature high frequency selectivity and wideband harmonic suppression. Based on these studies, several integrated filtering array antennas with improved gains and frequency responses are developed for the first time. Compared with traditional array antennas, these proposed antennas exhibit improved bandwidths, out-of-band rejection and wideband harmonic suppression. The application of the filtering antennas in millimeter-wave (mm-Wave) frequency band is also investigated as it can potentially reduce the cost of the mm-Wave front-end subsystems significantly while providing the improved impedance bandwidth. The integrated design techniques are further developed to design novel dual-port highly integrated antennas with filtering and duplexing functions integrated. Such a new concept and the prototypes could find poten-tial applications in wireless communication systems and intelligent transportation system (ITS). In this thesis, comprehensive design methodologies and synthesis methods are provid-ed to guide the design of the integrated filtering antennas. The performance is evaluated with the help of full-wave electromagnetics (EM) simulations. All of the prototypes are fabricated and tested for validating the design concepts. Good agreement between the simulation and measurement results is achieved, demonstrating the integrated antennas have the advantages of compact size, flat gain performance, low losses and excellent harmonic suppression performance. These researches are important for modern wireless communication systems.
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Li, Huanlu. "Integrated photonic devices for data communications". Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.682683.
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With the increasing capacity requirements of telecommunication systems, the ability to increase capacity density is of great importance for optical transmission technologies. This thesis presents several integrated photonic devices (semiconductor laser diodes and silicon devices) aimed at boosting the capacity density of the optical transmission systems. The first part of the thesis is about four wave mixing (FWM) effects in semiconductor ring lasers. Mode beating via third order nonlinearity in semiconductor ring lasers has been analysed using a frequency-domain multi-mode rate equation model. Compared with Fabry-Perot lasers, semiconductor ring lasers are found to be 1.33, 2, and 4 times more efficient in self-gain compression, cross-gain compression and four-wave mixing processes, respectively, due to its travelling-wave nature. It is shown that, using dual (pump and signal) external optical injections into the ring laser cavity, multiple modes can be locked in phase via the strong four wave mixing phenomenon. This results in modulation of the light wave at the mode beating frequencies which could be used for RF optical catrier generation. Secondly, following Bristol's research on compact optical vortex beam emitter based on silicon photonic micro-ring resonators, a different approach is demonstrated to simultaneously generate a pair of orbital angular momentum (OAM) modes with opposite topological charge by integrating a micro-ring OAM resonator with simple waveguide devices. The relative phase between two vortices can be actively modulated on the chip by thermo-optical controls. Furthermore, based on the ring cavity structure, OAM ring lasers on AlGaInAs/InP wafer are also developed. Detailed designs, fabrication processes and characterization of the device are discussed. In the last part of the thesis, a new approach is to propose and demonstrate directly generated optical OAM beams, by integrating a micro-scale spiral phase plate (SPP) on top of a vertical-cavity surface-emitting laser (VCSEL). The presence of the multi-level SPP transforms the linearly polarized Gaussian beam to a beam carrying specific OAM modes and their superposition states. The emitted OAM beams are characterized by usmg a spatial light modulator (SLM), and show good agreement with semi-analytical numerical simulation. The innovative OAM emitter opens a new horizon in the field of OAM-based optical and quantum communications, especially for low-cost short reach interconnects.
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Sibson, Philip. "Quantum secured communications with integrated photonics". Thesis, University of Bristol, 2016. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.705479.
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Hobson, Paula Lee. "Integrated marketing communications at community colleges". abstract and full text PDF (free order & download UNR users only), 2008. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1453583.
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Macken, Stephen. "Integrated Optical Solutions for Ubiquitous Sensing". Doctoral thesis, Linköpings universitet, Tillämpad Fysik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-63709.
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Ubiquitous chemical sensing aims at exploiting consumer electronic devices as temporary chemical sensing platforms. These devices are a highly disseminated infrastructure, not presently being exploited for chemical sensing purposes. The goal of the ubiquitous chemical sensing field is to create the methodologies and adapted devices to profit from this unexploited resource. DVD drives, flat bed scanners and computer screens used in combination with web cameras, and mobile phones have been demonstrated as measuring platforms, during the past 10 years. In particular the combination of computer screens with web cameras, a technique called the computer screen photo-assisted technique (CSPT), is the most versatile approach to support multiple types of optical detection phenomena, and together with mobile phones are the most ubiquitous type of platforms. The versatility of CSPT comes from the ease with which one can configure a spectrally controlled, 2D micro-positioned, linearly polarized, wide angle and internally modulated illumination with a programmable screen, just by controlling the displayed contents. Concurrently, the imaging devices in CSPT enable one to capture arbitrary assay layouts, the evaluation of which can then be numerically customized. The full exploitation of the CSPT platform requires optically adapted sensing interfaces and specialized methods, in order to increase sensitivity and make use of all available information, for a thorough and complete chemical sensing analysis. In this thesis I have explored the foundations of CSPT sensing on integrated devices, developing methods and sensing’s interfaces that provide enhanced optical detection customized to the CSPT platform.
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Cleary, Alison. "Integrated optical technologies for analytical sensing". Thesis, University of Glasgow, 2004. http://theses.gla.ac.uk/6607/.
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Recent diversification of the telecommunications industry has resulted in the adaptation of optical materials and their associated fabrication technologies for use in the bioanalytical sensor industry. Flame hydrolysis deposited (FHD) planar silica is one such material. Capable of producing high quality films for optical waveguides, the chemical inertness of the deposited silica makes it an ideal substrate from which to fabricate a biological fluorescence sensor. The aim of the work contained in this thesis was to utilise the FHD silica in optical - fluorescence sensors suitable for use at visible and in particular red wavelengths where several fluorophores can be excited, and background fluorescence from the silica is small. New technologies for producing waveguides have been evaluated in the context of their usefulness in optical sensors, with the intention of producing devices with as few fabrication steps as possible to reduce fabrication time and cost. The design, fabrication and testing of a number of sensor configurations is described, in which optical waveguides were interfaced with microfluidic chambers to provide excitation of a fiuorophore in solution. New waveguide fabrication technologies were used for the first time in sensor systems with integrated microfluidic circuits. Waveguides, written by electron beam densification were evaluated in terms of their performance in splitting an excitation signal into several different components, as would be appropriate for excitation of multiple microfluidic chambers - an 'array sensor'. Both Y-branch waveguides and multimode interference (MMI) splitters were successfully used to split the excitation signal. In addition to electron beam densification, UV irradiation at a wavelength of 157 nm was used to write waveguides in FHD silica. The application of a metal surface mask to define the waveguide structures is described. To allow sensitive detection and identification of fluorophores from FHD silica sensor chips, a single chamber device was successfully interfaced to a system to make time resolved fluorescence measurements, a technique known as time correlated single photon counting (TCSPC). The use of TCSPC allowed measurement of the decay time of the fluorescent dye, by which different fluorescent molecules could be identified, as well as the possibility of low concentration measurements. The research has allowed new technologies for creating waveguides in FHD silica to be adapted for sensing purposes, leading to a platform for creating devices in a number of different configurations.
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Kreidly, Fikrie, Abdikadar Aden e Adnan Tvrtkovic. "Integrated Marketing Communications : A quantitative study of the perceptions of integrated marketing communications in the Swedish market". Thesis, Linnéuniversitetet, Institutionen för marknadsföring (MF), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-35476.
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When planning to implement a marketing tool such as Integrated Marketing Communication (IMC) into ones company, marketers need to know what IMC means or is perceived to be in their environment. The definition of IMC is shown in the background chapter of this study and more definitions are stated in the theoretical frame chapter as well. Months of research lead to the conduction of a study, that is to test the perception of IMC in the Swedish market by sampling and sending questionnaires to Swedish marketers. Five Hypotheses were formed to test if each factor has a positive or negative relation with IMC. A questionnaire was formulated that tested all of the five main success factors (customer focus, targeted communication, customer-brand relationship, synergy and communication channels) in relation to IMC and how the Swedish marketers perceived each one of the factor’s connection to IMC. The marketers were chosen due to the fact that they would know most about IMC since it’s within the field of marketing. It was found that Swedish marketers support 2 out of the 5 hypotheses. This means that the results showed that Swedish marketers perceive that there is a positive relationship between both channels of communication and IMC, and customer brand relationship and IMC, while targeted communication, customer focus and synergy were denied to be as positively related to IMC. This study would be of great help to a Swedish company trying to implement IMC because it gives directions to the Swedish perception of it, thereby making it more clear to know exactly what they are implementing, which help them find out in what way they should implement IMC, in order to avoid failures that could be very expensive.
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Capdevila, Cascante Santiago. "RFID multiantenna systems for wireless communications and sensing". Doctoral thesis, Universitat Politècnica de Catalunya, 2013. http://hdl.handle.net/10803/116854.
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Many scientific, industrial and medical applications require the measurement of different physical parameters in order to collect information about the spatially distributed status of some process. Very often this information needs to be collected remotely, either due to the spatial dispersion of the measurement points or due to their inaccessibility. A wireless embedded self-powered sensor may be a convenient solution to be placed at these inaccessible locations. This thesis is devoted to study the analytical relation governing the electromagnetic coupling between a reader and a embeddable self-powered sensor, based on radio frequency identification (RFID) technology, which is capable of wirelessly retrieving the status of physical parameters at a remote and inaccessible location. The physical parameter to be sensed may be the electromagnetic (EM) field existing at that location (primary measurement) or the indirect measurement of other parameters such as the temperature, humidity, etc. (secondary measurement). Given the simplicity of the RFID solution (highly embeddable properties, scavenging capabilities, penetration and radio coverage characteristics, etc.) the measurement can be done at a single location, or it can be extended to a set of measuring locations (an array or grid of sensors). The analytical relation is based on a reciprocity formulation studying the modulation of the scattered field by the embedded sensor in relation with the incident field, and allows to define a set of quality parameters of interest for the optimum design of the sensors. Particular attention is given to the scavenging circuitry as well as to the antenna design relevant to the sensing objective. In RFID tags, the existence of an RF harvesting section is an improvement with respect to conventional scattering field probes since it removes the need of DC biasing lines or optical fibers to modulate the sensor. However, this harvesting section introduces non-linearities in the response of the sensor, which requires a proper correction to use them as EM-field probes, although the characterization of the non-linearities of the RFID tag cannot be directly done using a conventional vector network analyzer (VNA), due to the requirements of an RFID protocol excitation. Due to this, this thesis proposes an alternative measurement approach that allows to characterize the different scattering states used for the modulation, in particular its non-linear behavior. In addittion, and taking this characterization as the starting point, this thesis proposes a new measurement setup for EM-field measurements based on the use of multiple tones to enlarge the available dynamic range, which is experimentally demonstrated in the measurement of a radiation pattern, as well as in imaging applications.
The RFID-based sensor response is electromagnetically sensitive to the dielectric properties of its close environment. However, the governing formulation for the response of the probe mixes together a set of different contributions, the path-loss, the antenna impedance, the loads impedance, etc. As a consequence, it is not possible to isolate each contribution from the others using the information available with a conventional RFID sensor. This thesis mathematically proposes and experimentally develops a modification of the modulation scheme to introduce a new set of multi-load scattering states that increases the information available in the response and properly isolate each term. Moreover, this thesis goes a step forward and introduces a new scattering state of the probe sensitive to temperature variations that do not depend on the environment characteristics. This new configuration enables robust environmental sensing in addition to EM-field measurements, and sensing variations of the dielectric properties of the environment.
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Giza, Patryk J. Giza. "Fusion of Sensing and Backscatter Communications via OFDM". Miami University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=miami1470337743.
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Nair, Girish. "Communications within a computer integrated manufacturing environment". Master's thesis, This resource online, 1990. http://scholar.lib.vt.edu/theses/available/etd-01262010-020049/.
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Chamberlain, Adam W. "Integrated Surface-Plasmon Waveguides for Optical Communications". UKnowledge, 2005. http://uknowledge.uky.edu/gradschool_theses/258.
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Integrated optics present a potentially low cost and higher performance alternative to electronics in optical communication systems. Surface plasmon waveguides (SPWGs) offer a new approach for manipulating light in integrated optical chips. SPWGs provide several advantages over dielectric waveguides. In this study, a fabrication process for SPWGs is developed. SPWGs are fabricated with various lengths and bend radii to allow for study of absorption and bending losses in the waveguides at telecommunications wavelengths (~1550nm). Finite-element method models of straight, bent, and optically coupled waveguides are developed and analyzed.
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Bennecer, Abdeldjalil. "Low cost integrated lasers for data communications". Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609254.
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Schaaf, Kristin Leigh. "Composite materials with integrated embedded sensing networks". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3307537.
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Thesis (Ph. D.)--University of California, San Diego, 2008.Title from first page of PDF file (viewed July 23, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 116-120).
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Ma, Hanbin. "Impedance based integrated circuits for biological sensing". Thesis, University of Cambridge, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648847.
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Kelly, Devin WW. "A Practical Distributed Spectrum Sensing System". Digital WPI, 2011. https://digitalcommons.wpi.edu/etd-theses/378.
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As the demand for wireless communication systems grows, the need for spectrum grows accordingly. However, a large portion of the usable spectrum has already been exclusively licensed to various entities. This exclusive allocation method encourages spectrum to be left unused if the licensee has no need for that spectrum. In order to better utilize spectrum and formulate new approaches for greater spectrum use efficiency, it is imperative to possess a thorough understanding about how wireless spectrum behaves over time, frequency, and space. In this thesis, a practical, scalable, and low-cost wideband distributed spectrum sensing system is designed, implemented, and tested. The proposed system is made up of a collection of nodes that use general purpose, off-the-shelf computer hardware as well as a collection of inexpensive software-defined radio (SDR) equipment in order to collect and analyze spectrum data that varies across time, frequency, and space. The spectrum data the proposed system collects is the power present at a given frequency. The tools needed to analyze the gathered data are also created, including a periodogram and spectrogram function, which visualize average spectrum use over a period of time and as spectrum use varies with time, respectively. The proposed system also facilitates the testing of a spatio-spectrum characterization method using real data. This method has only been simulated up to this point. The characterization technique allows for spatially varying spectrum measurements to be visualized using heat maps.
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Jin, Xian. "Integrated optical devices for free-space optical communications". Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/17406.
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Optical wireless communication technologies for free-space optical (FSO) transmission, distribution, and reception have numerous potential benefits. Such systems offer incredibly high data communication rates (in the same way that fibre optic technologies have revolutionized long-haul Terabit/second data transmission) together with the distributive benefits of multi-user wireless networking. Communication devices for these FSO technologies are presented in this thesis. A macroscopic passive retroreflective structure is introduced first for signal retroreflection over the full 4π steradians solid angle. Modulation is demonstrated with this structure through the use of liquid crystal switching elements. The FSO device work is then extended with an active retroreflective structure incorporating corner-cube-based retro-detection with integrated and orthogonal photodiodes. An actively-controlled differential triangulation process is demonstrated with this novel device to optimize the optical channel alignment in the FSO communication system. The proposed integrated retroreflective structures are ideally-suited to bi-directional (uplink and downlink) multi-nodal systems and have potential to be extended to ultrafast (picosecond) optical modulation in future work.
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Metcalfe, Christian Todd 1974. "MediaJacket : an integrated clothing based personal communications system". Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/62093.
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Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 1999.Includes bibliographical references (leaves 46-47).
Recent developments in fabric based conductive embroidered input devices has created the opportunity for the next generation of wearable computing. This thesis presents a preliminary attempt to develop a wearable, multi-purpose, extensible, IP device that uses flexible fabric based circuitry for its user interface. It integrates a suite of advanced communications devices into a standard PolarTecTMjacket using an embedded personal computer for its controller. Users wear the MediaJacket similarly to normal clothing, and can use a diverse set of applications that include IP telephony, two-way pager-like email, an MP3 audio player, and a contactless "interface pocket" for handling input data streams from external devices. By embedding advanced electronics into clothing using an RF connection for tetherless internet connectivity, this research aims to reduce the stigma of using technology by creating a more personalized user experience. It is our hope, that as the size and cost of the MediaJacket's components come down, this research will help people better to better integrate technology into their lives.
by Christian Todd Metcalfe.
S.M.
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Marriott, A. P. "An integrated approach to image sensing and processing". Thesis, University of Manchester, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293261.
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Hannel, Thaddaeus S. "PATTERN RECOGNITION INTEGRATED SENSING METHODOLOGIES (PRISMS) IN PHARMACEUTICAL PROCESS VALIDATION, REMOTE SENSING AND ASTROBIOLOGY". UKnowledge, 2009. http://uknowledge.uky.edu/gradschool_diss/751.
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Modern analytical instrumentation is capable of creating enormous and complex volumes of data. Analysis of large data volumes are complicated by lengthy analysis time and high computational demand. Incorporating real-time analysis methods that are computationally efficient are desirable for modern analytical methods to be fully utilized. The use of modern instrumentation in on-line pharmaceutical process validation, remote sensing, and astrobiology applications requires real-time analysis methods that are computationally efficient.
Integrated sensing and processing (ISP) is a method for minimizing the data burden and sensing time of a system. ISP is accomplished through implementation of chemometric calculations in the physics of the spectroscopic sensor itself. In ISP, the measurements collected at the detector are weighted to directly correlate to the sample properties of interest. This method is especially useful for large and complex data sets. In this research, ISP is applied to acoustic resonance spectroscopy, near-infrared hyperspectral imaging and a novel solid state spectral imager. In each application ISP produced a clear advantage over the traditional sensing method.
The limitations of ISP must be addressed before it can become widely used. ISP is essentially a pattern recognition algorithm. Problems arise in pattern recognition when the pattern-recognition algorithm encounters a sample unlike any in the original calibration set. This is termed the false sample problem. To address the false sample problem the Bootstrap Error-Adjusted Single-Sample Technique (BEST, a nonparametric classification technique) was investigated. The BEST-ISP method utilizes a hashtable of normalized BEST points along an asymmetric probability density contour to estimate the BEST multidimensional standard deviation of a sample. The on-line application of the BEST method requires significantly less computation than the full algorithm allowing it to be utilized in real time as sample data is obtained. This research tests the hypothesis that a BEST-ISP metric can be used to detect false samples with sensitivity > 90% and specificity > 90% on categorical data.
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Pruessner, Marcel Werner. "Indium phosphide based optical waveguide MEMS for communications and sensing". College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2731.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Electrical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Delvecchio, Matthew David. "Enhancing Communications Aware Evasion Attacks on RFML Spectrum Sensing Systems". Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/99792.
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Recent innovations in machine learning have paved the way for new capabilities in the field of radio frequency (RF) communications. Machine learning techniques such as reinforcement learning and deep neural networks (DNN) can be leveraged to improve upon traditional wireless communications methods so that they no longer require expertly-defined features. Simultaneously, cybersecurity and electronic warfare are growing areas of focus and concern in an increasingly technology-driven world. Privacy and confidentiality of communication links are both more important and more difficult than ever in the current high threat environment. RF machine learning (RFML) systems contribute to this threat as they have been shown to be successful in gleaning information from intercepted signals, through the use of learning-enabled eavesdroppers. This thesis focuses on a method of defense against such communications threats termed an adversarial evasion attack in which intelligently crafted perturbations of the RF signal are used to fool a DNN-enabled classifier, therefore securing the communications channel.
One often overlooked aspect of evasion attacks is the concept of maintaining intended use. In other words, while an adversarial signal, or more generally an adversarial example, should fool the DNN it is attacking, this should not come at the detriment to it's primary application. In RF communications, this manifests in the idea that the communications link must be successfully maintained with friendly receivers, even when executing an evasion attack against malicious receivers. This is a difficult scenario, made even more so by the nature of channel effects present in
over-the-air (OTA) communications, as is assumed in this work.
Previous work in this field has introduced a form of evasion attack for RFML systems called a communications aware attack that explicitly addresses the reliable communications aspect of the attack by training a separate DNN to craft adversarial signals; however, this work did not utilize the full RF processing chain and left residual indicators of the attack that could be leveraged for defensive capabilities. First, this thesis focuses on implementing forward error correction (FEC), an aspect present in most communications systems, in the training process of the attack. It is shown that introducing this into the training stage allows the communications aware attack to implicitly use the structure of the coding to create smarter and more efficient adversarial signals. Secondly, this thesis then addresses the fact that in previous work, the resulting adversarial signal exhibiting significant out-of-band frequency content, a limitation that can be used to render the attack ineffective if preprocessing at the attacked DNN is assumed. This thesis presents two novel approaches to solve this problem and eliminate the majority of side content in the attack. By doing so, the communications aware attack is more readily applicable to real-world scenarios.Master of Science
Deep learning has started infiltrating many aspects of society from the military, to academia, to commercial vendors. Additionally, with the recent deployment of 5G technology, connectivity is more readily accessible than ever and an increasingly large number of systems will communicate with one another across the globe. However, cybersecurity and electronic warfare call into question the very notion of privacy and confidentiality of data and communication streams. Deep learning has further improved these intercepting capabilities. However, these deep learning systems have also been shown to be vulnerable to attack. This thesis exists at the nexus of these two problems, both machine learning and communication security. This work expands upon adversarial evasion attacks meant to help elude signal classification at a deep learning-enabled eavesdropper while still providing reliable communications to a friendly receiver. By doing so, this work both provides a new methodology that can be used to conceal communication information from unwanted parties while also highlighting the glaring vulnerabilities present in machine learning systems.
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Oliveira, Ricardo Jorge Figueiredo. "Novel techniques and devices for optical communications and sensing technologies". Doctoral thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/23653.
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Doutoramento em Engenharia FísicaHoje em dia, a tecnologia de fibra óptica está a ser amplamente usada nas áreas de telecomunicações e sensores. Historicamente, as qualidades das fibras ópticas poliméricas (POFs) têm sido menosprezadas devido à popularidade das fibras óticas de vidro. Tal facto advém maioritariamente da sua elevada atenuação. No entanto, os materiais que compõem as POFs têm vindo a melhorar significativamente nestes últimos anos. Nesse sentido, a emergência de novas técnicas e dispositivos têm vindo a ser demonstradas/os. Considerando o campo das telecomunicações, as POFs estão a crescer rapidamente em aplicações de redes de acesso. Além disso, o advento da operação monomodo e das redes de Bragg em POF estão a ser amplamente explorados em aplicações de sensores e portanto, este tipo de tecnologia tenderá a ser uma realidade num futuro próximo. Devido à necessidade de criar uma conexão de baixa perda entre fibra óptica de vidro e polimérica, será demonstrada uma nova técnica capaz de produzir terminais de POF de alta qualidade, num processo rápido, fácil e semiautomático. A conectorização destes tipos de fibras será também analisada nesta dissertação. No seguimento desta tese serão desenvolvidos dois sistemas de gravação de redes de Bragg em POF. Num dos sistemas será usado o tradicional laser de HeCd com operação nos 325 nm, sendo que noutro será usado o laser de KrF com operação nos 248 nm. Os resultados mostrarão a capacidade de gravar redes de Bragg em POF em apenas alguns segundos, contrariamente às várias dezenas de minutos necessários com o laser de 325 nm. Com base no sucesso dos resultados, o sistema de gravação que opera nos 248 nm será usado para fabricar redes de Bragg noutros tipos de fibras, incluindo as de índice em degrau, micro-estruturadas e sem bainha. A gravação de redes de Bragg de excelente qualidade em POFs de elevada birrefringência também será apresentada. A separação entre picos de ressonância irá ser usada para estimar a birrefringência de fase, que será então comparada com a obtida por simulações numéricas e com recurso ao método de varredura de comprimento de onda. As redes de Bragg produzidas pelos métodos anteriores serão então caracterizadas à deformação, temperatura, pressão, humidade e índice de refracção. Os resultados serão comparados com a literatura e com aqueles encontrados teoricamente. Um dispositivo de interferência multimodal feito pela conexão de duas fibras ópticas monomodo de vidro a uma fibra óptica multimodo de polímero, será usado para demonstrar a medição de deformação e temperatura. As capacidades de absorção de água, oferecidas pelo material à base de polimetilmetacrilato serão usadas para medir humidade. No final desta dissertação, um sensor híbrido composto por um dispositivo de interferência multimodal, baseado em POF e contendo uma rede de Bragg, demonstrará a capacidade de medir deformação, temperatura e índice de refracção. A propriedades de baixa absorção de água por parte do material que compõe a fibra polimérica será usada para demonstrar insensibilidade à humidade por parte do sensor.
Nowadays, fiber optic technology is being widely employed in communication and sensing areas. Historically, the qualities of polymer optical fibers (POFs) have been overwhelmed by the popularity of the silica optical fibers. This has been mainly due to the POFs higher transmission loss. However, in last years, POF materials are improving their performance. Therefore, the emergence of new devices and techniques have been demonstrated. Considering the communications field, POFs are growing rapidly in fiber to the home applications. Additionally, the advent of single mode operation and fiber Bragg gratings in POFs are being widely explored in several sensing applications. Consequently, this technology will tend to be a reality in a near future. Due to the need of a low loss connection between silica and polymer optical fibers, it will be demonstrated a new technique capable to produce POF terminals of high quality in an easy, fast and semi-automated process. The connectorization of these types of fibers will be then analysed in this dissertation. The development of two Bragg grating inscription systems for POFs will also be explored in this thesis. One of the systems will employ the traditional HeCd laser operating at 325 nm, while the other will use the KrF laser operating at 248 nm. Results will show the capability to write Bragg gratings in a POF in few seconds, contrary to the several tens of minutes reported for the 325 nm radiation. Based on the success of the results, the 248 nm inscription setup will be used to inscribe Bragg gratings in other types of POFs, including step-index, microstructured, and unclad POFs. The inscription of a high quality Bragg grating in a high-birefringence POF will also be presented and the phase birefringence arising from the Bragg peak separation will be compared with the numerical simulations togheter with the wavelength scanning method. The fiber Bragg gratings produced through the previous methods will be characterized to strain temperature, pressure, humidity and refractive index. Results will be compared with literature and with the ones found theoretically. A multimode interference device made by sandwiching a multimode POF between two single mode silica fibers will be used to demonstrate the ability to measure strain and temperature. The water absorption capabilities offered by the polymethylmethacrylate material will be used to measure humidity. At the end of this dissertation, a hybrid sensor composed of a POF based multimode interference device, comprising a fiber Bragg grating, will demonstrate the capability to measure strain, temperature and refractive index. The low water absorption properties of the material that composes the POF will be used to demonstrate a POF sensor with humidity insensitiveness.
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Lu, Guojun. "Graphics and video communications over an integrated services network". Thesis, Loughborough University, 1989. https://dspace.lboro.ac.uk/2134/28220.
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There is currently much interest in Integrated Services Systems which handle within one network or architecture a mixture of data, graphics, video and voice, although most of the work to date has concentrated on the voice and data services. This thesis is concerned with the provision of graphics and video services alongside the voice and data services over a Wide Area Network (WAN). The network concerned in this thesis is the Unison network, which comprises several Local Area Networks (LANs) interconnected by a primary rate (2 Mb/s) Integrated Service Digital Link.
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Yin, Dongliang. "Integrated hollow core waveguide devices for optical sensing applications /". Diss., Digital Dissertations Database. Restricted to UC campuses, 2006. http://uclibs.org/PID/11984.
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Szajda, Kenneth S. (Kenneth Stanley). "A high resolution integrated circuit biomedical temperature sensing system". Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11846.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Vita.
Includes bibliographical references (p. 226-235).
by Kenneth S. Szajda.
Ph.D.
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Hauke, Adam J. "An Integrated System for Sweat Stimulation, Sampling and Sensing". University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535371796736114.
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Messenger, Robert K. "Integrated Piezoresistive Sensing for Feedback Control of Compliant MEMS". Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2115.pdf.
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Liu, Qiankun. "SiGe photonic integrated circuits for mid-infrared sensing applications". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS166/document.
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La spectroscopie dans le moyen-infrarouge est une méthode universelle pour identifier les substances chimiques et biologiques, car la plupart des molécules ont leurs résonances de vibration et de rotation dans cette plage de longueurs d'onde. Les systèmes moyen infrarouge disponibles dans le commerce reposent sur des équipements volumineux et coûteux, tandis que de nombreux efforts sont maintenant consacrés à la réduction de leur taille et leur intégration sur circuits intégrés. L’utilisation de la technologie silicium pour la réalisation de circuits photoniques dans le moyen-infrarouge présente de nombreux avantages: fabrication fiable, à grand volume, et réalisation de circuits photoniques à hautes performances, compacts, légers et à faible consommation énergétique. Ces avantages sont particulièrement intéressant pour les systèmes de détection spectroscopique moyen infrarouge, qui besoin d'être portable et à faible coût. Parmi les différents matériaux disponibles en photonique silicium, les alliages silicium-germanium (SiGe) à forte concentration en Ge sont particulièrement intéressants en raison de la grande fenêtre de transparence du Ge, pouvant atteindre 15 µm. Dans ce contexte, l'objectif de cette thèse est d'étudier une nouvelle plate-forme SiGe à forte concentration en Ge, pour la démonstration de circuits photoniques moyen infra rouge. Cette nouvelle plate-forme devrait bénéficier d'une large gamme de transparence en longueurs d'onde de transparence et de la possibilité d’ajuster les propriétés des guides optiques (indice effectif, dispersion,…). Au cours de cette thèse, différentes plates-formes basées sur différents profils graduels du guide d’onde ont été étudiées. Tout d'abord, il a été démontré qu’il était possible d’obtenir des guides présentant de faibles pertes optiques inférieures à 3 dB/cm dans une large plage de longueurs d'onde, de 5,5 à 8,5 µm. Une preuve de concept de détection de molécules, basée sur l'absorption de la partie évanescent du mode optique a ensuite été démontrée. Ensuite, les composants formant les briques de base classiques de la photonique intégrée ont été étudiés. Les premières cavités intégrées ont été réalisées à 8 µm. Deux configurations ont été étudiées : des cavité Fabry-Perot utilisant des miroirs de Bragg intégrés dans les guides d’onde et des résonateurs en anneau. Un spectromètre à transformée de Fourier fonctionnant sur une large bande spectrale, et pour les deux polarisations de la lumière a également été démontré. Tous ces résultats reposent sur la conception des matériaux et des composants, la fabrication en salle blanche et la caractérisation expérimentale. Ce travail a été effectué dans le cadre du projet européen INsPIRE en collaboration avec le Pr. Giovanni Isella de Politecnico Di MilanoMid-infrared (mid-IR) spectroscopy is a nearly universal way to identify chemical and biological substances, as most of the molecules have their vibrational and rotational resonances in the mid-IR wavelength range. Commercially available mid-IR systems are based on bulky and expensive equipment, while lots of efforts are now devoted to the reduction of their size down to chip-scale dimensions. The use of silicon photonics for the demonstration of mid-IR photonic circuits will benefit from reliable and high-volume fabrication to offer high performance, low cost, compact, lightweight and power consumption photonic circuits, which is particularly interesting for mid-IR spectroscopic sensing systems that need to be portable and low cost. Among the different materials available in silicon photonics, Germanium (Ge) and Silicon-Germanium (SiGe) alloys with a high Ge concentration are particularly interesting because of the wide transparency window of Ge up to 15 µm. In this context, the objective of this thesis is to investigate a new Ge-rich graded SiGe platform for mid-IR photonic circuits. Such new plateform was expected to benefit from a wide transparency wavelength range and a high versatility in terms of optical engineering (effective index, dispersion, …). During this thesis, different waveguides platforms based on different graded profiles have been investigated. First it has been shown that waveguides with low optical losses of less than 3 dB/cm can be obtained in a wide wavelength range, from 5.5 to 8.5 µm. A proof of concept of sensing based on the absorption of the evanescent component of the optical mode has then been demonstrated. Finally, elementary building blocs have been investigated. The first Bragg mirror-based Fabry Perot cavities and racetrack resonators have been demonstrated around 8 µm wavelength. A broadband dual-polarization MIR integrated spatial heterodyne Fourier-Transform spectrometer has also been obtained. All these results rely on material and device design, clean-room fabrication and experimental characterization. This work was done in the Framework of EU project INsPIRE in collaboration with Pr. Giovanni Isella from Politecnico Di Milano
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DEMATTEIS, NICCOLÒ. "Integrated ground-based remote sensing sensors for glaciological monitoring". Doctoral thesis, Università degli studi di Pavia, 2020. http://hdl.handle.net/11571/1317327.
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Glaciological processes, such as glacier break-offs, snow/ice avalanches, can threaten the population, urban areas and infrastructures. For their potential hazard, it is necessary to study their activity in order to understand their possible geophysical dynamics evolution and to develop strategies of preventive alert and mitigation actions.
Therefore, the first step of this observation-alert-mitigation framework is the monitoring of such phenomena. One of the most relevant parameters to be investigated is the surface deformation, as it provides a direct measurement of the process activity.
The gravitational slope processes are common in mountain environment and hence they are often placed in harsh and remote areas. Therefore, a practical approach for their monitoring is the adoption of remote-sensing apparatuses, which allow at not accessing into possible perilous investigated areas, with consequent reduction of human resources and risks.
The remote sensing systems can be classified into two main categories: i) systems installed on aerospace platforms and ii) ground-based sensors. The first group provides data at global scale and the recent free availability of satellite constellations such as Sentinel 1 e Sentinel 2 is making their use widely studied. However, such systems suffer limitation of low temporal resolution, with revisiting time of days or weeks. The data availability of specific and localised areas is not always guaranteed and/or it can require high financial costs (e.g., airborne surveys, private satellite constellations). Moreover, complex geometries, typical of gravitational processes located in mountain areas, can affect the data acquisition.
By contrast, ground-based apparatuses are able to acquire data in environments with complex geometry. Furthermore, they can often operate in continuous, therefore providing data with high spatio-temporal resolution.
In general, a single monitoring system is able to measure specific parameters that can partially describe the state and the evolution of the investigated phenomenon. Therefore, a common approach consists in adopt different sensors and to collect separately their measurements to obtain a more comprehensive outline of the process. However, the independent analysis of the data of each sensor might not be sufficient to exploit all the available information. Rather, merging the different data in a coupled model can provide more informative results. Moreover, the data coupling allows at exploiting the qualities and potentialities of each sensor and to minimise their limits.
However, the realisation of an integrated system requires an accurate assessment of the instrument capacities. Therefore, the first step of such realisation involves the characterisation of the monitoring devices. Moreover, the development of specific and innovative processing techniques might be necessary to optimise the coupling process.
The methodologies developed for processing data of single and coupled sensors can be applied to practical case studies where the monitoring of gravitational slope phenomena can yield results about their present geophysical state, their dynamics and their possible evolution.
This text presents a collection of articles published in international scientific journals. The papers represent the work conducted during the PhD whose focus was the development of methodologies for coupling data collected by different sensors to monitor glaciological processes.
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Koch, Thomas Bertold. "Computation of wave propagation in integrated optical devices". Thesis, University College London (University of London), 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338284.
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Ghasemi, Farshid. "Multiplexed label-free integrated photonic biosensors". Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53633.
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Optics and photonics enable important technological solutions for critical areas such as health, communications, energy, and manufacturing. Novel nanofabrication techniques, on the other hand, have enabled the realization of ever shirking devices. On-chip photonic micro-resonators, the fabrication of which was made possible in the recent decade thanks to the progress in nanofabrication, provide a sensitive and scalable transduction mechanism that can be used for biochemical sensing applications. The recognition and quantification of biological molecules is of great interest for a wide range of applications from environmental monitoring and hazard detection to early diagnosis of diseases such as cancer and heart failure. A sensitive and scalable biosensor platform based on an optimized array of silicon nitride microring resonators is proposed for multiplexed, rapid, and label-free detection of biomolecules. The miniature dimension of the proposed sensor allows for the realization of handheld detection devices for limited-resource and point-of-care applications. To realize these sensors, the design, fabrication, stabilization, and integration challenges are addressed. Especially, the focus is placed on solving a major problem in using resonancebased integrated photonic sensors (i.e., the insufficiency of wavelength scan accuracy in typical tunable lasers available) by using an interferometric referencing technique for accurate resonance tracking. This technique can improve the limit of detection of the proposed sensor by more than one order of magnitude. The method does not require any temperature control or cooling, and the biosensor platform does not require narrow linewidths necessary for the biosensors based on ultrahigh quality factor resonators, thus enabling low-cost and reliable integration on the biosensor platform.
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Alghamdi, Owayed A. "Spectrum sensing and cooperation in cognitive-OFDM based wireless communications networks". Thesis, University of Plymouth, 2012. http://hdl.handle.net/10026.1/1090.
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The world has witnessed the development of many wireless systems and applications. In addition to the large number of existing devices, such development of new and advanced wireless systems increases rapidly the demand for more radio spectrum. The radio spectrum is a limited natural resource; however, it has been observed that it is not efficiently utilized. Consequently, different dynamic spectrum access techniques have been proposed as solutions for such an inefficient use of the spectrum. Cognitive Radio (CR) is a promising intelligent technology that can identify the unoccupied portions of spectrum and opportunistically uses those portions with satisfyingly high capacity and low interference to the primary users (i.e., licensed users). The CR can be distinguished from the classical radio systems mainly by its awareness about its surrounding radio frequency environment. The spectrum sensing task is the main key for such awareness. Due to many advantages, Orthogonal Frequency Division Multiplexing system (OFDM) has been proposed as a potential candidate for the CR‟s physical layer. Additionally, the Fast Fourier Transform (FFT) in an OFDM receiver supports the performance of a wide band spectrum analysis. Multitaper spectrum estimation method (MTM) is a non-coherent promising spectrum sensing technique. It tolerates problems related to bad biasing and large variance of power estimates. This thesis focuses, generally, on the local, multi antenna based, and global cooperative spectrum sensing techniques at physical layer in OFDM-based CR systems. It starts with an investigation on the performance of using MTM and MTM with singular value decomposition in CR networks using simulation. The Optimal MTM parameters are then found. The optimal MTM based detector theoretical formulae are derived. Different optimal and suboptimal multi antenna based spectrum sensing techniques are proposed to improve the local spectrum sensing performance. Finally, a new concept of cooperative spectrum sensing is introduced, and new strategies are proposed to optimize the hard cooperative spectrum sensing in CR networks. The MTM performance is controlled by the half time bandwidth product and number of tapers. In this thesis, such parameters have been optimized using Monte Carlo simulation. The binary hypothesis test, here, is developed to ensure that the effect of choosing optimum MTM parameters is based upon performance evaluation. The results show how these optimal parameters give the highest performance with minimum complexity when MTM is used locally at CR. The optimal MTM based detector has been derived using Neyman-Pearson criterion. That includes probabilities of detection, false alarm and misses detection approximate derivations in different wireless environments. The threshold and number of sensed samples controlling is based on this theoretical work. In order to improve the local spectrum sensing performance at each CR, in the CR network, multi antenna spectrum sensing techniques are proposed using MTM and MTM with singular value decomposition in this thesis. The statistical theoretical formulae of the proposed techniques are derived including the different probabilities. The proposed techniques include optimal, that requires prior information about the primary user signal, and two suboptimal multi antenna spectrum sensing techniques having similar performances with different computation complexity; these do not need prior information about the primary user signalling. The work here includes derivations for the periodogram multi antenna case. Finally, in hard cooperative spectrum sensing, the cooperation optimization is necessary to improve the overall performance, and/or minimize the number of data to be sent to the main CR-base station. In this thesis, a new optimization method based on optimizing the number of locally sensed samples at each CR is proposed with two different strategies. Furthermore, the different factors that affect the hard cooperative spectrum sensing optimization are investigated and analysed and a new cooperation scheme in spectrum sensing, the master node, is proposed.
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Tang, Xinyao. "Privacy-preserving Sensing and Wireless Communications for IoT-enabled Smart Environments". Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1607713752973587.
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Sparrer, Susanne [Verfasser]. "Algorithms for (discrete) compressed sensing : a communications engineering perspective / Susanne Sparrer". Ulm : Universität Ulm, 2020. http://d-nb.info/1216949271/34.
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DI, NATALE ANTONIO. "Modeling and Experimentation of short range communications for sensing and IoT". Doctoral thesis, Università degli Studi dell'Aquila, 2021. http://hdl.handle.net/11697/168385.
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The thesis reports the mathematical models, experimental results and related activities for the development of wireless devices in short-range communication systems aimed at sensing and the Internet of Things. The work originates from the idea of Wireless Body Area Network where low-cost sensors and communicarion systems can be worn or integrated into clothes. Subsequently, the investigation was extended to devices external to the body to be used as laboratory sensors or as a communication device.
The first part of the work dealt with the design and construction of wearable, fully textile and reconfigurable Ultra Wide Band (UWB) antennas for Wireless Body Area Network (WBAN) applications. These antennas have the ability to be used in two different configurations (monopole, microstrip), in order to change the topology of the short-range network and the type of communication (on-body communication and off-body communication). The obtained antennas are then used in the realization of a wearable radio-localization system on the principle of harmonic RADAR. A completely passive device, which allows to replicate the received signal in second harmonic, has been designed and built in order to be integrated into wearable UWB antennas. One envisaged use concerns the radio-localization of people whitin post-disaster scenarios or by connecting it to a transducer (for example of temperature) it can be used as a sensor.
For the development of textile antennas, it has been envisaged the use of non-conventional dielectric materials, such as fabrics, paper, plastic and organic materials with the aim to use them in the design and construction of low cost and low environmental impact sensors and antennas in the microwave band. For that purpose, their dielectric characterization has been necessary. A permittivity measurement system has been designed based on the ring resonator principle which has elements of versatility and can also be used for the characterization of some types of liquid material. In this context, the research has been extended to the design and construction of low-cost microwave microfluidic sensors for the characterization of acqueous solutions and liquids in general.
For what concerns the development of sensors to be used in laboratory, a completely passive RFId (Radio Frequency Identification) tag at 867 MHz has been designed and realized, in order to use it as a sensor in breaking test activities in the laboratory. The designed sensor exploits the variation of the input impedance of a twin line with variable parameters (tapered).
Finally, in the context of reconfigurable beam antennas, a Low Noise Amplifier was designed and built to be replicated on the branches of the beam forming network of an antenna array operating at 5 GHz for Wi-Fi (Wi-Fi5) applications. The developed LNA has the peculiarity to work not only as a low-noise amplifier but also as a microwave switch which, when properly piloted, allows the reconfiguration of the antenna beam. This solution avoids the use of microwave switches or circulators and thus reduces the noise of the receiving chain and the overall dimensions.
46
Smartt, Christopher James. "Fourier methods for the analysis of integrated optics devices". Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294708.
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47
Javed, Gaggatur Syed. "Integrated Interfaces for Sensing Applications". Thesis, 2016. http://etd.iisc.ac.in/handle/2005/2914.
Texto completo da fonteResumo:
Sensor interfaces are needed to communicate the measured real-world analog values to the base¬band digital processor. They are dominated by the presence of high accuracy, high resolution analog to digital converters (ADC) in the backend. On most occasions, sensing is limited to small range measurements and low-modulation sensors where the complete dynamic range of ADC is not utilized. Designing a subsystem that integrates the sensor and the interface circuit and that works with a low resolution ADC requiring a small die-area is a challenge. In this work, we present a CMOS based area efficient, integrated sensor interface for applications like capacitance, temperature and dielectric-constant measurement. In addition, potential applica-tions for this work are in Cognitive Radios, Software Defined Radios, Capacitance Sensors, and location monitoring.
The key contributions in the thesis are:
1 High Sensitivity Frequency-domain CMOS Capacitance Interface: A frequency domain capacitance interface system is proposed for a femto-farad capacitance measurement. In this technique, a ring oscillator circuit is used to generate a change in time period, due to a change in the sensor capacitance. The time-period difference of two such oscillators is compared and is read-out using a phase frequency detector and a charge pump. The output voltage of the system, is proportional to the change in the input sensor capacitance. It exhibits a maximum sensitivity of 8.1 mV/fF across a 300 fF capacitance range.
2 Sensitivity Enhancement for capacitance sensor: The sensitivity of an oscillator-based differential capacitance sensor has been improved by proposing a novel frequency domain capacitance-to-voltage (FDC) measurement technique. The capacitance sensor interface system is fabricated in a 130-nm CMOS technology with an active area of 0.17mm2 . It exhibits a maximum sensitivity of 244.8 mV/fF and a measurement resolution of 13 aF in a 10-100 fF measurement range, with a 10 pF nominal sensor capacitance and an 8-bit ADC.
3 Frequency to Digital Converter for Time/Distance measurement: A new architecture for a Vernier-based frequency-to-digital converter (VFDC) for location monitoring is pre¬sented, in which, a time interval measurement is performed with a frequency domain approach. Location monitoring is a common problem for many mobile robotic applica¬tions covering various domains, such as industrial automation, manipulation in difficult areas, rescue operations, environment exploration and monitoring, smart environments and buildings, robotic home appliances, space exploration and probing. The proposed architecture employs a new injection-locked ring oscillator (ILR) as the clock source. The proposed ILR oscillator does not need complex calibration procedures, usually required by Phase Locked Loop (PLL) based oscillators in Vernier-based time-to-digital convert¬ers. It consumes 14.4 µW and 1.15 mW from 0.4 V and 1.2 V supplies, respectively. The proposed VFDC thus achieves a large detectable range, fine time resolution, small die size and low power consumption simultaneously. The measured time-difference error is less than 50 ps at 1.2 V, enabling a resolution of 3 mm/kHz frequency shift.
4 A bio-sensor array for dielectric constant measurement: A CMOS on-chip sensor is presented to measure the dielectric constant of organic chemicals. The dielectric constant of these chemicals is measured using the oscillation frequency shift of a current controlled os¬cillator (CCO) upon the change of the sensor capacitance when exposed to the liquid. The CCO is embedded in an open-loop frequency synthesizer to convert the frequency change into voltage, which can be digitized using an off-chip analog-to-digital converter. The dielectric constant is then estimated using a detection procedure including the calibration of the sensor.
5 Integrated Temperature Sensor for thermal management: An integrated analog temper¬ature sensor which operates with simple, low-cost one-point calibration is proposed. A frequency domain technique to measure the on-chip silicon surface temperature, was used to measure the effects of temperature on the stability of a frequency synthesizer. The temperature to voltage conversion is achieved in two steps i.e. temperature to frequency, followed by frequency to voltage conversion. The output voltage can be used to com¬pensate the temperature dependent errors in the high frequency circuits, thereby reduc¬ing the performance degradation due to thermal gradient. Furthermore, a temperature measurement-based on-chip self test technique to measure the 3 dB bandwidth and the central frequency of common radio frequency circuits, was developed. This technique shows promise in performing online monitoring and temperature compensation of RF circuits.
48
Javed, Gaggatur Syed. "Integrated Interfaces for Sensing Applications". Thesis, 2016. http://hdl.handle.net/2005/2914.
Texto completo da fonteResumo:
Sensor interfaces are needed to communicate the measured real-world analog values to the base¬band digital processor. They are dominated by the presence of high accuracy, high resolution analog to digital converters (ADC) in the backend. On most occasions, sensing is limited to small range measurements and low-modulation sensors where the complete dynamic range of ADC is not utilized. Designing a subsystem that integrates the sensor and the interface circuit and that works with a low resolution ADC requiring a small die-area is a challenge. In this work, we present a CMOS based area efficient, integrated sensor interface for applications like capacitance, temperature and dielectric-constant measurement. In addition, potential applica-tions for this work are in Cognitive Radios, Software Defined Radios, Capacitance Sensors, and location monitoring.
The key contributions in the thesis are:
1 High Sensitivity Frequency-domain CMOS Capacitance Interface: A frequency domain capacitance interface system is proposed for a femto-farad capacitance measurement. In this technique, a ring oscillator circuit is used to generate a change in time period, due to a change in the sensor capacitance. The time-period difference of two such oscillators is compared and is read-out using a phase frequency detector and a charge pump. The output voltage of the system, is proportional to the change in the input sensor capacitance. It exhibits a maximum sensitivity of 8.1 mV/fF across a 300 fF capacitance range.
2 Sensitivity Enhancement for capacitance sensor: The sensitivity of an oscillator-based differential capacitance sensor has been improved by proposing a novel frequency domain capacitance-to-voltage (FDC) measurement technique. The capacitance sensor interface system is fabricated in a 130-nm CMOS technology with an active area of 0.17mm2 . It exhibits a maximum sensitivity of 244.8 mV/fF and a measurement resolution of 13 aF in a 10-100 fF measurement range, with a 10 pF nominal sensor capacitance and an 8-bit ADC.
3 Frequency to Digital Converter for Time/Distance measurement: A new architecture for a Vernier-based frequency-to-digital converter (VFDC) for location monitoring is pre¬sented, in which, a time interval measurement is performed with a frequency domain approach. Location monitoring is a common problem for many mobile robotic applica¬tions covering various domains, such as industrial automation, manipulation in difficult areas, rescue operations, environment exploration and monitoring, smart environments and buildings, robotic home appliances, space exploration and probing. The proposed architecture employs a new injection-locked ring oscillator (ILR) as the clock source. The proposed ILR oscillator does not need complex calibration procedures, usually required by Phase Locked Loop (PLL) based oscillators in Vernier-based time-to-digital convert¬ers. It consumes 14.4 µW and 1.15 mW from 0.4 V and 1.2 V supplies, respectively. The proposed VFDC thus achieves a large detectable range, fine time resolution, small die size and low power consumption simultaneously. The measured time-difference error is less than 50 ps at 1.2 V, enabling a resolution of 3 mm/kHz frequency shift.
4 A bio-sensor array for dielectric constant measurement: A CMOS on-chip sensor is presented to measure the dielectric constant of organic chemicals. The dielectric constant of these chemicals is measured using the oscillation frequency shift of a current controlled os¬cillator (CCO) upon the change of the sensor capacitance when exposed to the liquid. The CCO is embedded in an open-loop frequency synthesizer to convert the frequency change into voltage, which can be digitized using an off-chip analog-to-digital converter. The dielectric constant is then estimated using a detection procedure including the calibration of the sensor.
5 Integrated Temperature Sensor for thermal management: An integrated analog temper¬ature sensor which operates with simple, low-cost one-point calibration is proposed. A frequency domain technique to measure the on-chip silicon surface temperature, was used to measure the effects of temperature on the stability of a frequency synthesizer. The temperature to voltage conversion is achieved in two steps i.e. temperature to frequency, followed by frequency to voltage conversion. The output voltage can be used to com¬pensate the temperature dependent errors in the high frequency circuits, thereby reduc¬ing the performance degradation due to thermal gradient. Furthermore, a temperature measurement-based on-chip self test technique to measure the 3 dB bandwidth and the central frequency of common radio frequency circuits, was developed. This technique shows promise in performing online monitoring and temperature compensation of RF circuits.
49
Bastos, Ana Rita Naia. "Green photonics: photonic integrated circuits for optical communications and sensing based on organic-inorganic hybrids". Doctoral thesis, 2018. http://hdl.handle.net/10773/25027.
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The present work aims the production and characterization of cost-effective photonic integrated circuits (PICs) to encounter green photonics goals, namely in the optical communications and sensing fields. Therefore, organic-inorganic hybrids (di-ureasil and tri-ureasil), doped with zirconium propoxide stabilized with methacrylic acid, were synthesized by the versatile sol-gel methodology, at room temperature, as planar waveguides processed in the form of monoliths, with controlled shape and size, and films with variable thickness (10−5-10−6 m) in vitreous or silicon oxide substrates. They exhibit stable and tunable properties, mechanical and thermal stability resulting from the synergy between the organic and inorganic counterparts. Their main feature is the heavily facilitated control of the surface optical properties by the inherent flexibility offered by these materials that are easily self-patterned by direct UV laser writing, and the refractive index tuning through chemical doping.
The influence of different concentrations of zirconia-based clusters (20-60 mol%) in the local structure of di-ureasils and tri-ureasils was studied through X-ray diffraction, nuclear magnetic resonance of 13C and 29Si atoms, infrared spectroscopy by Fourier transform, Raman spectroscopy by Fourier transform and thermogravimetry analysis. The relevant optical features for applications in PICs were determined, showing acceptable attenuation values (∼1-5 dB·cm−1) for low dimension circuits, and reduced insertion losses arising from the fibre-device similar refractive index (1.49-1.52). Taking advantage of the material photosensibility, direct UV laser writing was used to pattern the desired optical architecture on the surface of organic-inorganic hybrids.
In what concerns optical communications, passive and active devices were produced: a thermo-optic integrated variable wave plate device to control the state of polarization of an optical signal, showing a linear retardation coefficient of 17±1 °/°C; a 90° hybrid coupler to demodulate a 20 Gb/s quadrature phase shift keying transmission over 40 km of fibre, yielding a 2.5 dB power penalty, relatively to back-to-back; an electro-optic phase modulator based on a Mach-Zehnder interferometer (MZI) with a voltage shift required for a π phase change of 2.9±0.3 V; an optical amplifier in the blue spectral region for visible light communications with a maximum optical gain efficiency of 1.62±0.02 cm∙μJ−1.
In the sensing field, the development of portable low-cost PICs based biosensors for lab-on-a-chip devices are of great interest. Thus, a biosensor based on an MZI was produced to monitor the growing concentration of bacteria in a liquid medium, presenting a sensitivity of 2×10−4 RIU and limit of detection of 2.0 pg·mm−3.O presente trabalho tem como objetivos a produção e caracterização de circuitos de ótica integrada (OI) eficientes e de baixo custo, no contexto dos requisitos de fotónica sustentável, nomeadamente na área das comunicações óticas e dos sensores. Para isso, híbridos orgânico-inorgânicos (di-ureiasil e tri-ureiasil), dopados com propóxido de zircónio estabilizado com ácido metracrílico, foram sintetizados pela metodologia sol-gel, à temperatura ambiente, como guias de onda planares processados na forma de monólitos, com forma e tamanho controlados, ou filmes de espessura variável (10−5-10−6 m), em substratos vítreos e de silício oxidado. Estes materiais exibem propriedades óticas estáveis e ajustáveis, estabilidade mecânica e térmica resultantes da sinergia entre os componentes orgânicos e inorgânicos. A sua principal propriedade é o fácil controlo das propriedades óticas devido à inerente flexibilidade dos materiais que são auto-padronizados pela escrita direta por radiação ultravioleta (UV), e o controlo do índice de refração por dopagem química. A influência de diferentes concentrações de aglomerados de zircónio (20-60 mol%) na estrutura local dos di-ureails e tri-ureasils foi analisada através de difração de raio-X, ressonância magnética nuclear dos átomos de 13C e 29Si, espectroscopia de infravermelho por transformada de Fourier, espectroscopia Raman por transformada de Fourier e análise termogravimétrica. As características óticas relevantes para aplicações em OI foram determinadas, revelando coeficientes de atenuação aceitáveis (∼1-5 dB·cm−1) para circuitos de baixas dimensões, e baixas perdas de inserção devido à similaridade entre os índices de refração do dispositivo-fibra (1,49-1,52). Tomando partido da fotossensibilidade do material, foi utilizada a escrita direta por radiação UV para padronizar a arquitetura ótica desejada na superfície de híbridos orgânico-inorgânicos. No que respeita às comunicações óticas, foram produzidos dispositivos passivos e ativos: controlador de polarização termo-ótico para monitorizar o estado de polarização de um sinal ótico, apresentando um coeficiente de retardamento linear de 17±1 °/°C; um acoplador híbrido de 90° para demodular uma transmissão de quadratura de chaveamento de fase com 20 Gb/s em 40 km de fibra, resultando numa penalidade de potência de 2,5 dB comparativamente à configuração sem fibra; um modulador de fase eletro-ótico baseado num interferómetro Mach-Zehnder (MZI) com uma diferença de potencial para uma variação de fase de π de 2,9±0,3 V; amplificador ótico na região espectral do azul para comunicações óticas no visível com uma eficiência máxima de ganho ótico de 1,62±0,02 cm∙μJ–1. Na área dos sensores, o desenvolvimento de biosensores portáteis de baixo custo baseados em OI para dispositivos é de grande interesse. Sendo assim, um biosensor baseado na arquitetura de um MZI foi produzido para monitorizar a concentração de bactérias num meio líquido, apresentando uma sensibilidade de 2×10−4 RIU e um limite de deteção de 2,0 pg·mm−3.
Programa Doutoral em Telecomunicações
50
Lin, Yu-Rou, e 林毓柔. "On-Interposer Data Communication for 2.5D Heterogeneously Integrated Bio-Sensing Microsystems". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/95703399464979168233.
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碩士國立交通大學
電子工程學系 電子研究所
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2.5D integration allow to inter-chip communication between multiple chips with intra-chip interconnects. The interposer provides fast and low power chip-to-chip communication. In this thesis, an on-interposer bus (μ-SPI, serial peripheral interface) is presented for providing low power data communication in 2.5D heterogeneous integrations. The protocol of μ-SPI is designed by a hierarchical packetization technique based on the physical layer of SPI. The data width of μ-SPI is from 1-bit to 8-bit. To reduce the overhead of the header, the header of a packet is divided into two levels by the hierarchical packetization technique. The length of 1st level header is fixed for indicating the functionality of this packet. Based on the information of 1st level header, the 2nd level header is variable for providing wide range of the burst length, broadcasting selection and variable address. Moreover, a pseudo multi-master is proposed to replace the arbitration circuits via master passing. Only 1 master can exist by controlling MS_Flag in master/slave modules. The proposedμ-SPI is utilized in a 2.5D heterogeneously integrated bio-sensing microsystem. The average power of this on-interposer bus is only 23.2 µW at 1.8V and 100 KHz.