Measurement and Evaluation of Tx/ Rx Antennas for X-Band Radar System

This paper presents the performance evaluation of antennas for microwave transmission and reception in X-band radar systems. The transmitter (Tx) and receiver (Rx) antennas are fabricated on microstrip array structures. The antennas are connected to microwave circuits with transmission lines, coaxial cables, and microwave combiners and splitters. The designed antennas in X-band microwave operation for Tx and Rx parts were fabricated identically by 4x64 microstrip patch antennasin an array structure. The fabricated antennas were measured for return loss (S11), VSWR, radiation pattern, and Gain. The detail methods for the measurements are reported and their results are also discussed. The measured antenna gain of ~20dBi, and beam-width of ~20degreecan be obtained using the fabricated antennas at 9.4GHz microwave operation

Microwave Photonic Applications - From Chip Level to System Level

Die Vermischung von Mikrowellen- und optischen Technologien – Mikrowellenphotonik – ist ein neu aufkommendes Feld mit hohem Potential. Durch die Nutzung der Vorzüge beider Welten hat die Mikrowellenphotonik viele Anwendungsfälle und ist gerade erst am Beginn ihrer Erfolgsgeschichte. Der Weg für neue Konzepte, neue Komponenten und neue Anwendungen wird dadurch geebnet, dass ein höherer Grad an Integration sowie neue Technologien wie Silicon Photonics verfügbar sind. In diesem Werk werden zuerst die notwendigen grundlegenden Basiskomponenten – optische Quelle, elektro-optische Wandlung, Übertragungsmedium und opto-elektrische Wandlung – eingeführt. Mithilfe spezifischer Anwendungsbeispiele, die von Chipebene bis hin zur Systemebene reichen, wird der elektrooptische Codesign-Prozess veranschaulicht. Schließlich werden zukünftige Ausrichtungen wie die Unterstützung von elektrischen Trägern im Millimeterwellen- und THz-Bereich sowie Realisierungsoptionen in integrierter Optik und Nanophotonik diskutiert.The hybridization between microwave and optical technologies – microwave photonics – is an emerging field with high potential. Benefitting from the best of both worlds, microwave photonics has many use cases and is just at the beginning of its success story. The availability of a higher degree of integration and new technologies such as silicon photonics paves the way for new concepts, new components and new applications. In this work, first, the necessary basic building blocks – optical source, electro-optical conversion, transmission medium and opto-electrical conversion – are introduced. With the help of specific application examples ranging from chip level to system level, the electro-optical co-design process for microwave photonic systems is illustrated. Finally, future directions such as the support of electrical carriers in the millimeter wave and THz range and realization options in integrated optics and nanophotonics are discussed

Laminat-Basierte Integrationsplattformen für Millimeterwellen-RoF-Photodioden-Module

This thesis investigates the potential offered by cost-effective printed circuit technology (PCT) for the packaging of mm-wave photodiode (PD) modules, as an alternative to the commonly used integration approaches based on thin/ thick-films or co-fired ceramics. We will therefore analyze the limitations imposed by this technology, focusing on the loss mechanisms and the theoretical frequency limits due to the material properties of the laminates and the RF circuitry concepts, as well as limitations imposed by the resolution and tolerances achievable in the printed circuit board (PCB) manufacturing processes. For the RF circuitry design, we will investigate characteristics and performances of traditional planar transmission lines (PTL), in particular microstrips and grounded coplanar waveguides (GCPW), and innovative substrate integrated waveguides (SIW). We will show that via holes play a fundamental role in the RF circuitry design, as they ultimately decide the highest possible frequency, independently of other parameters like conductor and dielectric loss, or etching inaccuracies. In fact, it is found that they are vital to guarantee a correct functioning of both GCPW and SIW, by avoiding board resonances and interferences between different lines. We will show that the current PCB via-hole technology allows the development of circuits working up to at least the upper limit of the W-band. As conventional microstrips are subject to higher radiation in the mm-wave region, GCPWs will be preferred for practical applications, also by virtue of their other practical advantages, such as easily accessible ground planes, increased design freedom, and extended impedance range. We will thus introduce the first concept of mm-wave PD modules with rectangular waveguide (WR) output for E-band Radio-over-Fiber (RoF) applications based on PCT integration boards. A particular feature of the proposed integration approach, is that a photonic transmitter can conveniently be assembled without any mechanical modifications of the WR, using standard off-the-shelf WR components, therefore simplifying the assembly process and reducing the cost of the module. We will also show that the availability of laminates with low moisture absorption as dielectric carrier furthermore opens up the possibility to develop quasi-hermetic packages without the need of dedicated radomes to seal the WR opening. The developed PD module will be used in mm-wave RoF demonstrators in order to prove the suitability of our approach for the development of commercial communication systems: We will be able to show a successful, error-free, 1-Gb/s, wireless connectivity in the 70-GHz communication band, with a power penalty limited to 1.5 dB. We will also present several additional prototypes, which include dedicated, on-board, biasing circuits, to allow integration of in-house-developed PDs and commercial amplifiers, and other solutions to reduce the loss of the signal power. In order to overcome the shortcomings of microstrips and GCPWs, such as unwanted radiation and increased power dissipation due to high current densities, we will then introduce for the first time the PCB SIW in the packaging of mm-wave photonic transmitters. The properties and advantages of this innovative transmission line in terms of low loss and high integration will be investigated and assessed, showing that its unique configuration allows a superior control of radiation and interferences, and drastically reduces losses. This suggests its use in all mm-wave systems where long on-board interconnects are required. A new integration approach for the development of quasi-hermetic PD modules with in-package antennas based on PCB SIW will thus be presented, focusing in particular on non-directive data distribution systems. It will be shown that compact, low-loss, and quasi-hermetic packaging solutions can conveniently be designed making use of the PCB SIW. We will furthermore introduce innovative GCPW-to-SIW transitions necessary for the integration of PDs on SIW platforms. Theoretically predicted performances will be compared with experimentally determined performances for a specifically optimized 60-GHz band GCPW-to-SIW transition. Also, the design and optimization of mm-wave antennas for indoor 60 GHz RoF systems will be presented, testing their performance against PCB manufacture inaccuracies. Finally, we will show an example of a fully characterized integration platform for PD modules, confirming the suitability of PCB SIW for the development of future, low-loss, and cost-effective photonic RoF transmitters.Diese Arbeit untersucht das Potenzial kostengünstige Leiterplattentechnik (PCT) für das Packaging von Millimeter-Wellen-Photodioden (PD) als Alternative zu den üblicherweise verwendeten Dünn-/ Dickschicht-Substraten oder co-fired Keramiken einzusetzen. Zunächst werden die physikalischen Grenzen dieser PCT-Technologie hinsichtlich eines Einsatzes bei höchsten Frequenzen untersucht. Die materialbedingten Verlustwinkel im Millimeter-Wellen-Bereich aber auch Abstrahlverluste im Zusammenhang mit verschiedenen planaren Schaltungs¬konzepten werden sowohl theoretisch als auch experimentell untersucht. Zum Einsatz kommen hierbei neben konventionellen planaren Übertragungsleitungen (PTL), wie Mikrostreifen und Grounded-Coplanar-Waveguides (GCPW), auch innovative Substrat-Integrierte-Wellenleiter (SIW). Weiterhin wird der Einfluss prozessbedingter Parameter, wie die minimal erreichbare Strukturgröße sowie Fertigungs¬toleranzen, auf das Hochfrequenzverhalten analysiert. Die Arbeit wird zeigen, dass Durchkontaktierungen (engl. Via Holes) eine fundamentale Rolle spielen. Unabhängig von anderen Einflussgrößen wie den dielektrischen Verlusten, den Abstrahlverlusten oder Fertigungstoleranzen begrenzt die minimal erreichbare Strukturgröße der Vias das Hochfrequenz¬verhalten der PCT-Technologie. Es wird theoretisch und experimentell nachgewiesen, dass die Vias für GCPW und SIW auf PCT-Technologie erforderlich sind, um geringe Ausbreitungsverluste zu gewährleisten, sowie um Resonanzen im Übertragungsverhalten und elektrischen Überkoppeln zwischen benachbarten Leitungen zu unterdrücken. Die Arbeit zeigt, dass die aktuelle PCB-Technologie die Entwicklung von planaren Hochfrequenz-Schaltungen erlaubt, die bis zur oberen Grenze des W-Bands (ca. 110 GHz) anwendbar sind. Da Mikrostreifenleitungen bekanntermaßen erhöhte Abstrahlverluste im Millimeterwellen-Bereich aufweisen, werden für technologische Realisierungen GCPWs vorgezogen. GCPW bieten gegenüber Mikrostreifenleitungen auch weitere Vorteile, wie leicht zugängliche Erdungsebenen, eine erhöhte Gestaltungsfreiheit und einen deutlich erweiterten Abstimmbereich der Leitungs-Impedanz. Basierend auf der PCT-Technologie und einer planaren GCPW-Schaltung wird im Folgenden ein neuartiger Ansatz für die Anbindung von hochfrequenten InP-basierten Photodioden-Chips an einen Rechteckhohlleiter entwickelt. Ein besonderes Merkmal des in dieser Arbeit vorgeschlagenen Integrationsansatzes besteht darin, dass sich das Photodioden-Modul ohne eine mechanische Modifikation des Hohlleiters realisieren lässt, was hinsichtlich Montageprozess und -kosten einen deutlichen Vorteil darstellt. Die Arbeit zeigt auch, dass die Verwendung von Laminaten mit geringer Feuchtigkeitsaufnahme weiterhin die Möglichkeit eröffnet, quasi-hermetische Module ohne die sonst erforderlichen Radome zu realisieren. Da eine wesentliche Anwendung für solche hochfrequenten Photodioden-Module im Bereich der Funkkommunikation und speziell für die Entwicklung von Punkt-zu-Punkt-Funkverbindungen im E-Band (60-90 GHz) liegt, konzentriert sich diese Arbeit auf die Entwicklung einer PCT-Integrationstechnologie für E-Band-Photodioden-Module mit WR-12 Hohlleiter. Die Arbeit beschreibt das Design und die Herstellung der GCPW-PCT-Schaltung. Die theoretisch simulierten Streuparameter der GCPW-PCT-Schaltung werden mit experimentellen Werten verglichen, bevor im Anschluss näher auf die erfolgreiche technologische Realisierung eines Prototyp-Photodioden-Moduls mit WR-12-Hohlleiterausgang eingegangen wird. Die Funktionalität des entwickelten PD-Moduls wird durch Einsatz in einer 70-GHz-Funkstrecke nachgewiesen. Es gelingt die Funkübertragung eines 1-Gbit/s-Datensignals im regulierten 70-GHz-Frequenzbereich (71-76 GHz). Die Arbeit zeigt im Anschluss weitere Prototypen, welche die Integration von hausintern entwickelten Photodioden und kommerziellen RF-Verstärkern erlauben, sowie Lösungen zur Reduzierung des Signalleistungsverlusts. Obwohl die verwendeten GCPW im Vergleich zu Mikrostreifenleitungen geringere Abstrahlverluste aufweisen, kommt es bei hohen Frequenzen doch zu einer unerwünschten Dämpfung durch Strahlungs- und ohmsche Verluste aufgrund der hohen Stromdichten in der GCPW-Schaltung. Zur weiteren Reduzierung dieser Verluste werden in dieser Arbeit daher erstmalig SIW-PCB-Schaltungen für die Integration von Millimeterwellen-Photodioden vorgeschlagen und entwickelt. Die Vorteile dieser innovativen Leitungsstruktur hinsichtlich der elektrischen Dämpfung im Millimeterwellen-Bereich werden theoretisch und experimentell untersucht. Es kann gezeigt werden, dass die SIW-PCT gegenüber den GCPW-PCT signifikant geringere Verluste aufweisen, was insbesondere für den Einsatz in planaren Hochfrequenz-Schaltungen mit vergleichsweise langen Verbindungsleitungen vorteilhaft ist. Die Arbeit präsentiert eine neue Integrationstechnologie auf Basis planarer SIW-PCB-Schaltungen für quasi-hermetische PD-Module mit In-Package-Antennen. Es werden kompakte, verlustarme und quasi-hermetische SIW-basierte Lösungen für 60-GHz-PD-Module hergestellt und experimentell untersucht. Abschließend wird die Eignung der SIW-PCB-Technologie für die Entwicklung zukünftiger, verlustarmer und kostengünstiger photonischer Millimeter-Wellen-Funktransmitter diskutiert

Modern Applications in Optics and Photonics: From Sensing and Analytics to Communication

Optics and photonics are among the key technologies of the 21st century, and offer potential for novel applications in areas such as sensing and spectroscopy, analytics, monitoring, biomedical imaging/diagnostics, and optical communication technology. The high degree of control over light fields, together with the capabilities of modern processing and integration technology, enables new optical measurement systems with enhanced functionality and sensitivity. They are attractive for a range of applications that were previously inaccessible. This Special Issue aims to provide an overview of some of the most advanced application areas in optics and photonics and indicate the broad potential for the future

Non-Invasive Near-Field Measurement Setup Based on Modulated Scatterer Technique Applied to Microwave Tomographhy

Résumé L’objectif principal de cette thèse est d’aborder la conception et le développement d’un montage d’imagerie en champ proche (CP) basé sur la technique de diffusion modulé (TDM). La TDM est une approche bien connue et utilisée pour des applications où des mesures précises et sans perturbations sont nécessaire. Parmi les applications possibles disponibles pour la fabrication d’une sonde TDM, que ce soit électrique, optique, mécanique, le diffuseur optique modulé DOM a été pris en considération afin de fournir des mesures quasi sans-perturbations en raison de l’invisibilité des fibres optiques face aux champs radiofréquence électromagnétiques. La sonde est composée d’une puce photodiode commerciale “off-the-shelf” (dispositif non-linéaire), d’une antenne dipôle courte agissant comme diffuseur et un réseau d’adaptation (cir¬cuit passif). Cet dernieér améliore les propriétés de diffusion et augmente également la sensibilité de la sonde DOM dans la bande de fréquence pour laquelle le réseau correspondant est optimisé. Les caractéristiques de rayonnement de la sonde, y compris sa réponse de polarisation croisée et sa sensibilité omnidirectionnelle, ont été théoriquement et expérimentalement étudiés. Enfin, la performance et la fia¬bilité de la sonde a été étudiée en comparant des mesures de distribution de champs proche avec une distribution de champs simulé. Une vitesse d’imagerie accrue a été obtenue utilisant un réseau de sondes DOM, ce qui réduit les mouvements mécaniques résultant ansi en une amélioration remarquable de la vitesse de mesure. Le couplage mutuel, le temps de commutation et l’effet d’obscurité, des effets qui peuvent affecter les performances du réseau ont été explorés. Ensuite, les résultats obtenus par le réseau ont été validé par une imagerie CP en mesurant la distribution des champs E d’une antenne sous test (AST) et la comparant à des résultats de simulation. Une calibration et un calcul de moyenne ont été appliqués à des données brutes pour com¬penser pour les incertitudes dans la fabrication et l’interaction entre réseau/AST et réseau/antenne de réception. La plage dynamique et la linéarité de la réponse de l’imagerie CP ont été améliorées en ajoutant un circuit suppresseur de porteuse en avant de l’antenne. Le suppresseur élimine la porteuse sur laquelle aucune information n’est transmise et laisse les bandes latérales intactes.----------Abstract The main focus of this thesis is to address the design and development of a near-field (NF) imaging setup based on the modulated scatterer technique (MST). MST is a well-known approach used in applications where accurate and perturbation-free mea¬surement results are necessary. Of the possible implementations available for making an MST probe, including electrical, optical and mechanical, the optically modulated scatterer OMS was considered in order to provide nearly perturbation-free measure¬ment due to the invisibility of optical fiber to the radio-frequency electromagnetic fields. The OMS probe consists of a commercial, off-the-shelf (COTS) photodiode chip (nonlinear device), a short-dipole antenna acting as a scatterer and a match¬ing network (passive circuit). The latter improves the scattering properties and also increases the sensitivity of the OMS probe within the frequency range in which the matching network is optimized. The radiation characteristics of the probe, includ-ing cross-polarization response and omnidirectional sensitivity, were both theoreti¬cally and experimentally investigated. Finally, the performance and reliability of the probe was studied by comparing measured near-field distributions on a known field distribution with simulations. Increased imaging speed was obtained using an array of OMS probes, which re¬duces mechanical movements. Mutual-coupling, switching time and shadowing effect, which all may affect the performance of the array, were investigated. Then, the re¬sults obtained by the array were validated in a NF imager by measuring the E-field distribution of an antenna under test (AUT) and comparing it with a simulation. Cal¬ibration and data averaging were applied to raw data to compensate the probes for uncertainties in fabrication and interaction between array/AUT and array/receiving antenna. Dynamic range and linearity of the developed NF imager was improved by adding a carrier canceller circuit to the front-end of the receiver. The canceller eliminates the carrier on which no information is transmitted and leaves the sidebands intact. This enables us to increase the amplification gain to achieve better signal-to-noise ratio (SNR) and more importantly to expand the imager’s dynamic range

NASA Tech Briefs, April 2011

Topics covered include: Amperometric Solid Electrolyte Oxygen Microsensors with Easy Batch Fabrication; Two-Axis Direct Fluid Shear Stress Sensor for Aerodynamic Applications; Target Assembly to Check Boresight Alignment of Active Sensors; Virtual Sensor Test Instrumentation; Evaluation of the Reflection Coefficient of Microstrip Elements for Reflectarray Antennas; Miniaturized Ka-Band Dual-Channel Radar; Continuous-Integration Laser Energy Lidar Monitor; Miniaturized Airborne Imaging Central Server System; Radiation-Tolerant, SpaceWire-Compatible Switching Fabric; Small Microprocessor for ASIC or FPGA Implementation; Source-Coupled, N-Channel, JFET-Based Digital Logic Gate Structure Using Resistive Level Shifters; High-Voltage-Input Level Translator Using Standard CMOS; Monitoring Digital Closed-Loop Feedback Systems; MASCOT - MATLAB Stability and Control Toolbox; MIRO Continuum Calibration for Asteroid Mode; GOATS Image Projection Component; Coded Modulation in C and MATLAB; Low-Dead-Volume Inlet for Vacuum Chamber; Thermal Control Method for High-Current Wire Bundles by Injecting a Thermally Conductive Filler; Method for Selective Cleaning of Mold Release from Composite Honeycomb Surfaces; Infrared-Bolometer Arrays with Reflective Backshorts; Commercialization of LARC (trade mark) -SI Polyimide Technology; Novel Low-Density Ablators Containing Hyperbranched Poly(azomethine)s; Carbon Nanotubes on Titanium Substrates for Stray Light Suppression; Monolithic, High-Speed Fiber-Optic Switching Array for Lidar; Grid-Tied Photovoltaic Power System; Spectroelectrochemical Instrument Measures TOC; A Miniaturized Video System for Monitoring Drosophila Behavior; Hydrofocusing Bioreactor Produces Anti-Cancer Alkaloids; Creep Measurement Video Extensometer; Radius of Curvature Measurement of Large Optics Using Interferometry and Laser Tracker n-B-pi-p Superlattice Infrared Detector; Safe Onboard Guidance and Control Under Probabilistic Uncertainty; General Tool for Evaluating High-Contrast Coronagraphic Telescope Performance Error Budgets; Hidden Statistics of Schroedinger Equation; Optimal Padding for the Two-Dimensional Fast Fourier Transform; Spatial Query for Planetary Data; Higher Order Mode Coupling in Feed Waveguide of a Planar Slot Array Antenna; Evolutionary Computational Methods for Identifying Emergent Behavior in Autonomous Systems; Sampling Theorem in Terms of the Bandwidth and Sampling Interval; Meteoroid/Orbital Debris Shield Engineering Development Practice and Procedure; Self-Balancing, Optical-Center-Pivot, Fast-Steering Mirror; Wireless Orbiter Hang-Angle Inclinometer System; and Internal Electrostatic Discharge Monitor - IESDM

New photonic architectures and devices for generation and detection of sub-THz and THz waves

The development of high-quality and reliable devices in the THz frequency region to fill the existing technological gap has become a major concern. This is chiefly motivated by the need of a widespread exploitation of the extensive variety of identified applications in this frequency region by a wide range of users, including the non-scientific community. The photonic approaches used for these purposes offer important and exclusive advantages over other existing alternatives, which have as a main representative the all-electronic technology, especially in terms of frequency range coverage, possibility of photonic distribution using optical fibers, weight and Electromagnetic Interference (EMI) immunity. Nevertheless, the optical techniques have traditionally provided with worse performance in terms of phase noise, tunability and dynamic range (in generation), and conversion ratio (in detection) when compared to state-of-theart all-electronic THz technology. The work accomplished in this thesis focuses on the design, development and validation of new photonic architectures and devices for both generation and detection of sub-THz and THz waves which overcome the drawbacks of optical techniques at this frequency region while maintaining all their advantages. In this thesis, several photonic sub-THz and THz generation systems have been developed using Difference Frequency Generation (DFG) architectures in which the DFG source is provided by an Optical Frequency Comb Generator (OFCG) and optical mode selection. Different devices and techniques are investigated for each part of the system before arriving to the final high performance synthesizer. Passively Mode-Locked Laser Diodes (PMMLDs) are firstly evaluated as integrated OFCG. An improved design of the OFCG is achieved with a scheme based on a Discrete Mode (DM) laser under Gain- Switching (GS) regime and optical span expansion by the use of a single Electro- Optical (EO) phase modulator. As optical mode selection, both high selective optical filtering and Optical Injection Locking (OIL) are used and evaluated. A commercial 50 GHz photodiode (PD) and an n-i-pn-i-p superlattice THz photomixer are employed as photodetector for Optical to THz conversion. The final reported system consists on an OFCG based on GS, OIL as mode selection strategy and an n-i-pn-i-p superlattice photomixer. This synthesizer offers a wide frequency range (60-140 GHz), readily scalable to a range between 10 GHz and values well above 1 THz. Quasi-continuous tunability is offered in the whole frequency range, with a frequency resolution of 0.1 Hz at 100 GHz that can be straightforwardly improved to 0.01 Hz at 100 GHz and 0.1 Hz at 1 THz. The measured FWHM at 120 GHz is <10 Hz, only limited by the measurement instrumentation. The system offers excellent frequency and power stability with frequency and power deviations over 1 hour of 5 Hz and 1.5 dB, respectively. These values are also limited by both the accuracy and uncertainty of the measurement setup. The performance achieved by this photonic sub-THz and THz synthesizer for most figures of merit matches or even surpasses those of commercial stateof- the-art all-electronic systems, and overcomes some of their characteristics in more than one million times when compared to commercial state-of-the-art photonic solutions. The detection part of this thesis explores the use of photonic architectures based on EO heterodyne receivers and the key devices that encompass these architectures: photonic Local Oscillators (LOs) and EO mixers. First results are developed at microwave frequencies (<15 GHz) using an Ultra-Nonlinear Semiconductor Amplifier (XN-SOA) as EO mixer and a GS based photonic LO. It is demonstrated how this LO device based on GS provides with a significant improvement in the performance of the overall EO receiver when compared to a traditional linearly modulated LO. Furthermore, this detection architecture is validated in an actual application (photonic imaging array), featuring scalability, flexibility and reasonable conversion ratios. After this, an EO heterodyne receiver is demonstrated up to frequencies of 110 GHz. The photonic LO employed is the abovementioned photonic sub- THz synthesizer developed in this thesis, while the EO mixer is an np-i-pn quasi ballistic THz detector. The first fabricated sample of this novel device is used, which is optimized for homodyne/heterodyne detection. The resulting sub-THz EO heterodyne receiver has conversion ratios around -75 dB. It works under zero-bias conditions, which together with the photonic distribution of the LO offers a high potential for remote detection of sub-THz and THz waves. In summary, new photonic architectures and devices are able to provide with state-of-the-art performance for generation of sub-THz and THz waves. In the case of EO heterodyne detection at sub-THz and THz frequency regions, photonic techniques are improving their performance and are closer to offer an alternative to all-electronic detectors. ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------El desarrollo de dispositivos fiables y de alta calidad en el rango frecuencial de Terahercios (THz) con el fin de cubrir el actual vacío tecnológico se ha convertido en una importante inquietud científica. Esto está principalmente motivado por la necesidad de explotar el gran número de aplicaciones identificadas en esta región frecuencial por un gran número de usuarios, incluyendo a usuarios no científicos. El enfoque fotónico empleado para estos propósitos ofrece importantes y exclusivas ventajas sobre otras alternativas existentes, que tienen como principal representante a la tecnología electrónica, especialmente en términos de rango de frecuencia de funcionamiento, posibilidad de distribución fotónica con fibras ópticas, peso, e inmunidad electromagnética. No obstante, las técnicas fotónicas tradicionalmente han ofrecido peores prestaciones en términos de ruido de fase, sintonía y rango dinámico (en generación) y ratio de conversión (en detección) con respecto a la tecnología electrónica de THz en el estado del arte. El trabajo realizado en esta tesis se centra en el diseño, desarrollo y validación de nuevas arquitecturas y componentes fotónicos tanto para generación como detección de ondas de sub-THz y THz que permitan solucionar las desventajas de las técnicas ópticas manteniendo todas sus ventajas. En esta tesis, varios sistemas de generación de sub-THz y THz han sido desarrollados utilizando arquitecturas Difference Frequency Generation (DFG) en las que la fuente DFG es proveída por un Optical Frequency Comb Generator (OFCG) y selección de modos ópticos. Diferentes dispositivos y técnicas son investigados para cada parte del sistema hasta conseguir un sintetizador de altas prestaciones. Passively Mode-Locked Laser Diodes (PMMLDs) son inicialmente evaluados como OFCG integrados. Un diseño mejorado del OFCG es conseguido mediante el uso de un esquema basado en un láser Discrete Mode (DM) bajo régimen Gain Switching (GS) y expansión del ancho de banda óptico mediante el uso de un modulador de fase Electro-Óptico (EO). Como estrategia de selección de modos ópticos, tanto filtrado óptico altamente selectivo como Optical Injection Locking (OIL) son usados y evaluados. Un fotodiodo comercial de ancho de banda 50 GHz y un fotomezclador de THz de superred n-i-pn-i-p son empleados. El sistema de generación final que se presenta en esta tesis consiste en un OFCG basado en GS, OIL como técnica de selección de modos ópticos y un fotomezclador de THz de superred n-i-pn-i-p. Este sintetizador ofrece un rango de funcionamiento de 60 a 140 GHz, directamente escalable a un rango entre 10 GHz y valores más allá de un THz. Sintonía cuasi-continua es ofrecida en todo el rango de frecuencia de operación, con una resolución en frecuencia de 0.1 Hz a 100 GHz que puede ser directamente escalable a 0.01 Hz a 100 GHz y 0.1 Hz a 1 THz. El ancho de línea a 3-dB de la señal a 120 GHz es menor de 10 Hz, solo limitada por la instrumentación de medida. El sistema ofrece una excelente estabilidad en potencia y frecuencia, con desviaciones sobre una hora de operación de 1.5 dB y 5 Hz, respectivamente. Estos valores también están limitados por la precisión e incertidumbre de la instrumentación de medida. Las prestaciones conseguidas por este sintetizador fotónico de sub-THz y THz para la mayoría de figuras de mérito, igualan o superan aquellas de las mejores soluciones comerciales electrónicas en el estado del arte, y supera algunas de estas características en más de un millón de veces en el caso de soluciones fotónicas comerciales en el estado del arte. La parte de detección de esta tesis explora el uso de arquitecturas fotónicas basadas en receptores EO heterodinos y los componentes clave que forman estas arquitecturas: Oscilador Local (OL) fotónico y mezcladores EO. Los primeros resultados son desarrollados en el entorno de microondas (<15 GHz) usando un amplificador de semiconductor óptico ultra no lineal (XN-SOA) como mezclador EO y un OL fotónico basado en GS. Se demuestra como este OL basado en GS ofrece una mejora significativa de las prestaciones del receptor con respecto al uso de OL fotónicos tradicionales basados en modulación lineal. Además, esta arquitectura de detección es validada en una aplicación real (imaging array fotónico), ofreciendo escalabilidad, flexibilidad y ratios de conversión razonables. Tras esto, un receptor EO heterodino es demostrado hasta frecuencias de 110 GHz. El OL fotónico empleado es el sintetizador de altas prestaciones presentado en esta tesis, mientras que el mezclador EO es un nuevo detector de THz: el np-i-pn cuasi-balístico. La primera muestra fabricada de estos nuevos dispositivos, especialmente diseñados y optimizados para detección homodina y heterodina, es empleada. El receptor EO heterodino resultante ofrece ratios de conversión de -75 dB. Este dispositivo es capaz de trabajar sin alimentación, lo que unido a la distribución fotónica del OL, ofrece un gran potencial para detección remota de ondas de sub-THz y THz. En resumen, las nuevas arquitecturas y dispositivos fotónicos presentados en esta tesis son capaces de ofrecer prestaciones en el estado del arte para generación de ondas de sub-THz y THz. En el caso de detectores EO heterodinos en frecuencias de sub-THz y THz, las técnicas fotónicas están mejorando sus prestaciones significativamente y están cada vez más cerca de ofrecer una alternativa a detectores electrónicos en el estado del arte

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion