No description available.

No description available.

Yes / A novel dual-polarized patch antenna for ultra-wideband (UWB) applications is presented. The antenna consists of a square patch and four capacitively coupled feeds to enhance the impedance bandwidth. Each feed is formed by a vertical isosceles trapezoidal patch and a horizontal isosceles triangular patch. The four feeds are connected to the microstrip lines that are printed on the bottom layer of the grounded FR4 substrate. Two tapered baluns are utilized to excite the antenna to achieve high isolation between the ports and reduce the cross-polarization levels. In order to increase the antenna gain and reduce the backward radiation, a compact surface mounted cavity is integrated with the antenna. The antenna prototype has achieved an impedance bandwidth of 112% at (|S11| ≤ -10 dB) whereas the coupling between the two ports is below -28 dB across the operating frequency range. The measured antenna gain varies from 3.91 to 10.2 dBi for port 1 and from 3.38 to 9.21 dBi for port 2, with a 3-dB gain bandwidth of 107%. / IEEE Antennas and Propagation Society

Impulse Ultra Wideband (UWB) communications is an emerging technology that promises a number of benefits over traditional narrowband or broadband signals: extremely high data rates, extremely robust operation in dense multipath environments, low probability of intercept/detection, and the ability to operate concurrently with existing users. Unfortunately, most currently available UWB systems are based on dedicated hardware, preventing researchers from investigating algorithms or architectures that take advantage of some of the unique properties of UWB signals. This dissertation outlines the development of a general purpose software radio transceiver testbed for UWB signals. The testbed is an enabling technology that provides a development platform for investigating ultra wideband communication algorithms (e.g., acquisition, synchronization, modulation, multiple access), ranging or radar (e.g., precision position location, intrusion detection, heart and respiration rate monitoring), and could potentially be used in the area of ultra wideband based medical imaging or vital signs monitoring. As research into impulse ultra wideband expands, the need is greater now than ever for a platform that will allow researchers to collect real-world performance data to corroborate theoretical and simulation results. Additionally, this dissertation outlines the development of the Time-Interleaved Analog to Digital Converter array which served as the core of the testbed, along with a comprehensive theoretical and simulation-based analysis on the effects of Analog to Digital Converter mismatches in a Time-Interleaved Sampling array when the input signal is an ultra wideband Gaussian Monocycle. Included in the discussion is a thorough overview of the implementation of both a scaled-down prototype as well as the final version of the testbed. This dissertation concludes by evaluating the of the transceiver testbed in terms of the narrowband dynamic range, the accuracy with which it can sample and reconstruct a UWB pulse, and the bit error rate performance of the overall system. / Ph. D.

Las señales arbitrarias de microondas son ampliamente utilizadas en distintos campos de aplicacón como radar, comunicaciones, captura de imágenes e instrumentación moderna. La limitación de los sistemas eléctricos para la generación de formas de onda a frecuencias elevadas y con grandes anchos de banda ha hecho que a lo largo de la última década se realicen numerosas propuestas de generación en el dominio óptico. Tras una revisión de todas las propuestas, se ha podido realizar una clasificación en función de las técnicas de generación más relevantes. El principal objetivo de esta tesis doctoral consiste en la propuesta, análisis y validación experimental de una técnica que permite la generación de señales de microondas haciendo uso de estructuras de filtrado fotónico. En concreto, los filtros utilizados en este trabajo se fundamentan en el procesado de señales ópticas incoherentes mediante un elemento dispersivo. A través del desarrollo teórico, se ha obtenido la función de transferencia del filtro fotónico equivalente que permite calcular la señal generada a partir de la densidad espectral de potencia de la fuente óptica, la dispersión y la señal eléctrica de entrada. De este modo, ha sido posible extender algunas de las ventajas del filtrado fotónico a la generación de formas de onda. Así mismo, para la técnica propuesta se distinguen dos regímines de operación, no lineal y lineal, según sea necesario o no considerar la dispersión de segundo orden del elemento dispersivo. En el régimen lineal, se presentan varias estructruas que utilizan distintos tipos de señal óptica como un conjunto de láseres y una fuente ancha ranurada empleando diferentes tipos de filtrado óptico. Además, también se presenta una estructura adicional incorporando detección defierencial a través de un interferómetro. Con el fin de mostrar las distintas capacidades de estas propuestas se ha demostrado la generación de señales correspondientes a la tecnología UWB de impulsos de radio y multib / Bolea Boluda, M. (2012). Sistemas ópticos incoherentes para la generación de señales arbitrarias basados en filtros fotónicos de microondas [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/16810

Dielectric resonator antenna (DRA) technologies are applicable to a wide variety of mobile wireless communication systems. The principal energy loss mechanism for this type of antenna is the dielectric loss, and then using modern ceramic materials, this may be very low. These antennas are typically of small size, with a high radiation efficiency, often above 95%; they deliver wide bandwidths, and possess a high power handling capability. The principal objectives of this thesis are to investigate and design DRA for low profile personal and nomadic communications applications for a wide variety of spectrum requirements: including DCS, PCS, UMTS, WLAN, UWB applications. X-band and part of Ku band applications are also considered. General and specific techniques for bandwidth expansion, diversity performance and balanced operation have been investigated through detailed simulation models, and physical prototyping. The first major design to be realized is a new broadband DRA operating from 1.15GHz to 6GHz, which has the potential to cover most of the existing mobile service bands. This antenna design employs a printed crescent shaped monopole, and a defected cylindrical DRA. The broad impedance bandwidth of this antenna is achieved by loading the crescent shaped radiator of the monopole with a ceramic material with a permittivity of 81. The antenna volume is 57.0  37.5  5.8 mm3, which in conjunction with the general performance parameters makes this antenna a potential candidate for mobile handset applications. The next class of antenna to be discussed is a novel offset slot-fed broadband DRA assembly. The optimised structure consists of two asymmetrically located cylindrical DRA, with a rectangular slot feed mechanism. Initially, designed for the frequency range from 9GHz to 12GHz, it was found that further spectral improvements were possible, leading to coverage from 8.5GHz to 17GHz. Finally, a new low cost dual-segmented S-slot coupled dielectric resonator antenna design is proposed for wideband applications in the X-band region, covering 7.66GHz to 11.2GHz bandwidth. The effective antenna volume is 30.0 x 25.0 x 0.8 mm3. The DR segments may be located on the same side, or on opposite sides, of the substrate. The end of these configurations results in an improved diversity performance. / General Secretariat of Education and Scientific Research Libya

Among the low-power wireless technologies that have emerged in recent years, ultra-wideband (UWB) has successfully established itself as the reference for accurate ranging and localization, both outdoors and indoors. Due to its unprecedented performance, paired with relatively low energy consumption, UWB is going to play a central role in the next wave of location-based applications. As the trend of integration in smartphones continues, UWB is also expected to reach ordinary users, revolutionizing our lives the same way GPS and similar technologies have done. But the impact of UWB may not be limited to ranging and localization. Because of its considerable data rate, and its robustness to obstacles and interference, UWB communication may hold untapped potential for sensing and control applications. Nevertheless, several research questions still need to be answered to assess whether UWB can be adopted widely in the communication and localization landscapes. On one hand, the rapid evolution of UWB radios and the release of ever more efficient chips is a clear indication of the growing market for this technology. However, for it to become pervasive, full-fledged communication and localization systems must be developed and evaluated, tackling the shortcomings affecting current prototypes. UWB systems are typically single-hop networks designed for small areas, making them impractical for large-scale coverage. This limitation is found in communication and localization systems alike. Specifically for communication systems, energy-efficient multi-hop protocols are hitherto unexplored. As for localization systems, they rely on mains-powered anchors to circumvent the issue of energy consumption, in addition to only supporting small areas. Very few options are available for light, easy to deploy infrastructures using battery-powered anchors. Nonetheless, large-scale systems are required in common settings like industrial facilities and agricultural fields, but also office spaces and museums. The general goal of enabling UWB in spaces like these entails a number of issues. Large multi-hop infrastructures exacerbate the known limitations of small, single-hop, networks; notably, reliability and latency requirements clash with the need to reduce energy consumption. Finally, when device mobility is a factor, continuity of operations across the covered area is a challenge in itself. In this thesis, we design energy-efficient UWB systems for large-scale areas, supporting device mobility across multi-hop infrastructures. As our opening contribution, we study the unique interference rejection properties of the radio to inform our design. This analysis yields a number of findings on the impact of interference in communication and distance estimation, that are directly usable by developers to improve UWB solutions. These findings also suggest that concurrent transmissions in the same frequency channel are a practical option in UWB. While the overlapping of frames is typically avoided to prevent collisions, concurrent transmissions have counter-intuitively been used to provide highly reliable communication primitives for a variety of traffic patterns in narrowband radios. In our first effort to use concurrent transmissions in a full system, we introduce the UWB version of Glossy, a renowned protocol for efficient network-wide synchronization and data dissemination. Inspired by the success of concurrency-based protocols in narrowband, we then apply the same principles to define a novel data collection protocol, Weaver. Instead of relying on independent Glossy floods like state-of-the-art systems, we weave multiple data flows together to make our collection engine faster, more reliable and more energy-efficient. With Glossy and Weaver supporting the communication aspect in large-scale networks, we then propose techniques for large-scale localization systems. We introduce TALLA, a TDoA solution for continuous position estimation based on wireless synchronization. We evaluate TALLA in an UWB testbed and in simulations, for which we replicate accurately the behavior of the clocks in our real-world platforms. We then offer a glimpse of what TALLA can be employed for, deploying an infrastructure in a science museum to track visitors. The collected movement traces allow us to analyze fine-grained stop-move mobility patterns and infer the sequence of visited exhibits, which is only possible because of the high spatio-temporal granularity offered by TALLA. Finally, with SONAR, we tackle the issue of large-scale ranging and localization when the infrastructure cannot be mains-powered. By blending synchronization and scheduling operations into neighbor discovery and ranging, we drastically reduce energy consumption and ensure years-long system lifetime. Overall, this thesis enhances UWB applicability in scenarios that were previously precluded to the technology, by providing the missing communication and localization support for large areas and battery-powered devices. Throughout the thesis, we follow an experiment-driven approach to validate our protocol models and simulations. Based on the evidence collected during this research endeavor, we develop full systems that operate in a large testbed at our premises, showing that our solutions are immediately applicable in real settings.

[ES] La cápsula inalámbrica de endoscopia (WCE) es una tecnología notable y atractiva adoptada en el sector biomédico hace varios años. WCE proporciona una tecnología de imagen inalámbrica no invasiva que permite a los especialistas reconocer y diagnosticar enfermedades que afectan todo el tracto gastrointestinal. Aunque los médicos pueden recibir imágenes claras de anomalías en el tracto gastrointestinal, no tienen información sobre sus exacta ubicación. La localización precisa de los trastornos detectados es crucial para el posterior procedimiento de extracción mediante cirugía. Actualmente, la banda de frecuencia asignada para aplicaciones de cápsula endoscópica es la banda MICS (402-405 MHz) que ofrece una velocidad de datos de hasta 500 kbps, insuciente para transmitir imágenes de alta calidad. Recientemente, la tecnología de banda ultra ancha (UWB) ha estado atrayendo atención como posible candidato para la próxima generación de cápsula endoscópica. Las ventajas de UWB incluyen arquitecturas de transceptor simples que permiten bajo consumo de potencia, baja interferencia a otros sistemas y amplio ancho de banda que resulta en comunicaciones a una velocidad de datos más alta. En esta disertación, el rendimiento de las técnicas de localización de WCE basadas en radiofrecuencia (RF) se investiga a través de simulaciones software, medidas experimentales de laboratorio que involucran fantomas homogéneos y heterogéneos y a través de experimentos in vivo que constituyen el escenario de prueba más realista. La tecnología UWB (3.1-10.6 GHz) se considera como interfaz de comunicación para aplicaciones de cápsula endoscópica. En tal escenario, el transmisor inalámbrico está ubicado en el tracto gastrointestinal, mientras que uno o más receptores inalámbricos están ubicados sobre la supercie del cuerpo. El enfoque basado en la potencia recibida (RSS) se investiga principalmente debido a su simplicidad de implementación y menos sensibilidad a las limitaciones de ancho de banda. Se analiza el impacto de la posición y del número de receptores seleccionados en la precisión de la localización. Finalmente, se desarrolla una interfaz gráfica de usuario (GUI) para visualizar los resultados de la localización en tres dimensiones (3D) obtenidos mediante las medidas in vivo. / [CA] La càpsula sense fil d'endoscòpia (WCE) és una tecnologia notable i atractiva adoptada en el sector biomèdic fa diversos anys. La WCE proporciona una tecnologia d'imatge sense fil no invasiva que permet als especialistes reconéixer i diagnosticar malalties que afecten tot el tracte gastrointestinal. Encara que els metges poden rebre imatges clares d'anomalies en el tracte gastrointestinal, no tenen informació sobre les seues exacta ubicació. La localització precisa dels trastorns detectats és crucial per al posterior procediment d'extracció mitjançant cirurgia. Actualment, la banda de freqüència assignada per a aplicacions de càpsula endoscòpica és la banda MICS (402-405 MHz) que ofereix una velocitat de dades de fins a 500 kbps, insucient per a transmetre imatges d'alta qualitat. Recentment, la tecnologia de banda ultra ampla (UWB) ha estat atraient atenció com a possible candidata per a la pròxima generació de càpsula endoscòpica. Els avantatges d' UWB inclouen arquitectures de transceptor simples que permeten un baix consum de potència, baixa interferència amb altres sistemes i una gran amplada de banda que resulta en comunicacions a una velocitat de dades més alta. En aquesta dissertació, el rendiment de les tècniques de localització de WCE basades en radiofrequència (RF) s'investiga a través de simulacions amb programari, mesures experimentals de laboratori que involucren fantomes homogenis i heterogenis i a través d'experiments in vivo que constitueixen l'escenari de prova més realista. La tecnologia UWB (3.1-10.6 GHz) es considera com a interfície de comunicació per a aplicacions de càpsula endoscòpica. En tal escenari, el transmissor sense fil està situat en el tracte gastrointestinal, mentre que un o més receptors sense fils estan situats sobre la superfície del cos. L'enfocament basat en la potència rebuda (RSS) s'investiga principalment a causa de la seua simplicitat d'implementació i menys sensibilitat a les limitacions d'amplada de banda. S'analitza l'impacte de la posició i del numere de receptors seleccionats en la precisió de la localització. Finalment, es desenvolupa una interfície gràca d'usuari (GUI) per a visualitzar els resultats de la localització en tres dimensions (3D) obtinguts mitjançant les mesures in vivo. / [EN] Wireless Capsule Endoscopy (WCE) is a remarkable and attractive technology adopted in the biomedical sector several years ago. It provides a non-invasive wireless imaging technology for the entire gastrointestinal (GI) tract. WCE allows specialists to recognize and diagnose diseases affecting the whole GI tract. Although physicians can receive clear pictures of abnormalities in the GI tract, they have no information about their exact location. Precise localization of the detected disorders is crucial for the subsequent removal procedure by surgery. Currently, the frequency band allocated for capsule endoscopy applications is the MICS band (402-405 MHz). This band offers data rate up to 500 kbps, which is insufficient to transmit high quality images. Recently, Ultrawideband (UWB) technology has been attracting attention as potential candidate for next-generation WCE systems. The advantages of UWB include simple transceiver architectures enabling low power consumption, low interference to other systems and wide bandwidth resulting in communications at higher data rate. In this dissertation, performance of WCE localization techniques based on Radio Frequency (RF) information are investigated through software simulations, experimental laboratory measurements involving homogeneous and heterogeneous phantom models and in vivo experiments which constitute the most realistic testing scenario. Ultra-Wideband technology (3.1-10.6 GHz) is considered as communication interface in Wireless Capsule Endoscopy. In such scenario, the wireless transmitter is located in the gastrointestinal track while one or more wireless receivers are located over the surface of the body. Received Signal Strength (RSS)-based approach is mainly explored due to its implementation simplicity and less sensitivity to bandwidth limitations. Impact of the position and the number of selected receivers on the localization accuracy is analyzed. Finally, a graphical user interface (GUI) is developed to visualize the three-dimensional (3D) localization results obtained through in vivo measurements. / Barbi, M. (2019). Location and Tracking for Ultra-WideBand In-Body Communications in Medical Applications [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/132874

This thesis investigates applicable indoor navigation systems for the next generation of hand-held shopping scanners, on behalf of the company Virtual Stores. The thesis research and review applicable indoor localization methods and ways to combine and evaluate received localization data in order to provide accurate navigation without introducing any other worn equipment for a potential user. Prototype navigation systems was proposed, developed and evaluated using a combination of carefully placed radio transmitters that was used to provide radio based localization methods using Bluetooth or UltraWide Band (UWB) and inertial sensors combined with a particle filter. The Bluetooth solution was deemed incapable of providing any accurate localization method while the prototype using a combination of UWB and inertial sensors proved promising solution with below 1m average error under optimal conditions or 2.0m average localization error in a more realistic environment. However, the system requires the surveyed area to provide 3 or more UWB transmitters in the line of sight of the UWB receiver of the user at every location facing any direction to provide accurate localization. The prototype also requires to be scaled up to provide localization to more than 1 radio transmitters at the time before being introduced to the Fast moving consumer goods market. / Denna avhandling undersöker tillämpliga inomhusnavigationssystem för nästa generations handhållna shopping terminaler, på uppdrag av företaget Virtual Stores. Avhandlingen undersöker och granskar tillämpliga inomhuslokaliseringsmetoder och sätt att kombinera och utvärdera mottagna lokaliseringsdata för att bistå med ackurat navigering utan att introducera någon ytterligare utrustning för en potentiell användare. Prototypnavigationssystem föreslogs, utvecklades och utvärderades användandes en kombination av väl utplacerade radiosändare användandes Bluetooth eller UltraWide Band (UWB) och tröghetssensorer i kombination med ett partikelfilter. Bluetooth-lösningen ansågs oförmögen att tillhandahålla någon exakt lokalisering medan prototypen som använde en kombination av UWB och tröghetssensorer visade sig vara en lovande lösnings med under 1m genomsnittligt fel under optimala förhållanden eller 2,0m genomsnittligt lokaliseringsfel i mer realistisk miljö. Systemet kräver emellertid att det undersökta området tillhandahåller 3 eller fler UWB-sändare inom synfältet för UWB-mottagaren hos användaren vid varje plats och riktning för att tillhandahålla ackurat lokalisering. Prototypen behöver skalas upp för att kunna bistå med lokalisering till mer än 1 radiomottagare innan den introduceras till detaljhandlen.

Approved for public release, distribution is unlimited / This thesis analyzes the feasibility, functionality, and usability of Ultra Wideband technology as an alternative to 802.11 in wireless mesh networks for multiple DoD contexts. Ultra wideband and wireless mesh network technologies and applications are researched and analyzed through multiple field and lab experiments for usability in current, real-world situations. Hardware and software investigations are conducted to determine any implementation issues between ultra wideband and wireless mesh networks. A detailed assessment is conducted of the various elements and operational constraints for developing an ultra wideband mesh network that can be utilized to improve situational awareness in network-centric operations. Through joint research with Lawrence Livermore National Laboratories, various hardware and software components are developed to create a test bed for tactical level ultra wideband and mesh networking experimentation in a highly mobile environment. This thesis also lays the groundwork into future ultra wideband and mesh networking applications. / Lieutenant, United States Navy