Active Backscattering Positioning System Using Innovative Harmonic Oscillator Tags for Future Internet of Things: Theory and Experiments

RÉSUMÉ D'ici 2020, l'Internet des objets (IoT) permettra probablement de créer 25 milliards d'objets connectés, 44 ZB de données et de débloquer 11 000 milliards de dollars d’opportunités commerciales. Par conséquent, ce sujet a suscité d’énormes intérêts de recherche dans le monde académique entier. L'une des technologies clés pour l'IoT concerne le positionnement physique intérieur précis. Le principal objectif dans ce domaine est le développement d'un système de positionnement intérieur avec une grande précision, une haute résolution, un fonctionnement à plusieurs cibles, un faible coût, un faible encombrement et une faible consommation d'énergie. Le système de positionnement intérieur conventionnel basé sur les technologies de Wi-Fi ou d'identification par radiofréquence (RFID) ne peut répondre à ces exigences. Principalement parce que leur appareil et leur signal ne sont pas conçus spécialement pour atteindre les objectifs visés. Les chercheurs ont découvert qu'en mettant en oeuvre de différents types de modulation sur les étiquettes, le radar à onde continue (CW) et ses dérivés deviennent des solutions prometteuses. Les activités de recherche présentées dans cette thèse sont menées dans le but de développer des systèmes de positionnement en intérieur bidimensionnel (2-D) à plusieurs cibles basées sur des étiquettes actives à rétrodiffusion harmonique avec une technique à onde continue modulée en fréquence (FMCW). Les contributions de cette thèse peuvent être résumées comme suit: Tout d'abord, la conception d'un circuit actif harmonique, plus spécifiquement une classe d'oscillateurs harmoniques innovants utilisée comme composant central des étiquettes actives dans notre système, implique une méthodologie de conception de signal de grande taille et des installations de caractérisation. L’analyseur de réseau à grand signal (LSNA) est un instrument émergent basé sur les fondements théoriques du cadre de distorsion polyharmonique (PHD). Bien qu'ils soient disponibles dans le commerce depuis 2008, des organismes de normalisation et de recherche tels que l’Institut national des normes et de la technologie (NIST) des États-Unis travaillent toujours à la mise au point d'un standard largement reconnu permettant d'évaluer et de comparer leurs performances. Dans ce travail, un artefact de génération multi-harmonique pour la vérification LSNA est développé. C'est un dispositif actif capable de générer les 5 premières harmoniques d'un signal d'entrée avec une réponse ultra-stables en amplitude et en phase, quelle que soit la variation de l'impédance de la charge.----------ABSTRACT By 2020, the internet of things (IoT) will probably enable 25 billion connected objects, create 44 ZB data and unlock 11 trillion US dollar business opportunities. Therefore, this topic has been attracting tremendous research interests in the entire academic world. One of the key enabling technologies for IoT is concerned with accurate indoor physical positioning. The development of such an indoor positioning system with high accuracy, high resolution, multitarget operation, low cost, small footprint, and low power consumption is the major objective in this area. The conventional indoor positioning system based on WiFi or radiofrequency identification (RFID) technology cannot fulfill these requirements mainly because their device and signal are not purposely designed for achieving the targeted goals. Researchers have found that by implementing different types of modulation on the tags, continuous-wave (CW) radar and its derivatives become promising solutions. The research activities presented in this Ph.D. thesis are carried out towards the goal of developing multitarget two-dimensional (2-D) indoor positioning systems based on harmonic backscattering active tags together with a frequency-modulated continuous-wave (FMCW) technique. Research contributions of this thesis can be summarized as follows: First of all, the design of a harmonic active circuit, more specifically, a class of innovative harmonic oscillators used as the core component of active tags in our system, involves a large signal design methodology and characterization facilities. The large signal network analyzer (LSNA) is an emerging instrument based on the theoretical foundation for the Poly-Harmonic Distortion (PHD) framework. Although they have been commercially available since 2008, standard and research organizations such as the National Institute of Standards and Technology (NIST) of the US are still working towards a widely-recognized standard to evaluate and cross-reference their performances. In this work, a multi-harmonic generation artifact for LSNA verification is developed. It is an active device that can generate the first 5 harmonics of an input signal with ultra-stable amplitude and phase response regardless of the load impedance variation

1-D broadside-radiating leaky-wave antenna based on a numerically synthesized impedance surface

A newly-developed deterministic numerical technique for the automated design of metasurface antennas is applied here for the first time to the design of a 1-D printed Leaky-Wave Antenna (LWA) for broadside radiation. The surface impedance synthesis process does not require any a priori knowledge on the impedance pattern, and starts from a mask constraint on the desired far-field and practical bounds on the unit cell impedance values. The designed reactance surface for broadside radiation exhibits a non conventional patterning; this highlights the merit of using an automated design process for a design well known to be challenging for analytical methods. The antenna is physically implemented with an array of metal strips with varying gap widths and simulation results show very good agreement with the predicted performance

Beam scanning by liquid-crystal biasing in a modified SIW structure

A fixed-frequency beam-scanning 1D antenna based on Liquid Crystals (LCs) is designed for application in 2D scanning with lateral alignment. The 2D array environment imposes full decoupling of adjacent 1D antennas, which often conflicts with the LC requirement of DC biasing: the proposed design accommodates both. The LC medium is placed inside a Substrate Integrated Waveguide (SIW) modified to work as a Groove Gap Waveguide, with radiating slots etched on the upper broad wall, that radiates as a Leaky-Wave Antenna (LWA). This allows effective application of the DC bias voltage needed for tuning the LCs. At the same time, the RF field remains laterally confined, enabling the possibility to lay several antennas in parallel and achieve 2D beam scanning. The design is validated by simulation employing the actual properties of a commercial LC medium

Bibliography of Lewis Research Center technical publications announced in 1993

This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1993. All the publications were announced in the 1993 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses