Rozprawy doktorskie na temat „Antennae”

Switched and adaptive parasitic monopole array radiating structures are investigated. Antenna design is orientated toward increasing practicability for implementation in terrestrial wireless communication systems. A number of antennas are designed with the aid of optimization and commercial simulation software. Simulation procedure was verified with the experimental manufacture and measurement of the arrays. The antennas presented in this thesis comprise an active monopole surrounded by a ring of parasitic monopoles. Parasitic radiators are constructed with static loading to enable simple experimental realization. Beam positions of an electrically steered equivalent antenna are thus simulated. Antenna symmetry ensures the beam can be reproduced throughout the azimuth. Complex antenna geometries require antenna design through optimization. A genetic algorithm is employed with HFSS and NEC for electromagnetic analysis. The robust optimization method couples with simulation software flexibility to provide an effective design tool for arbitrary structures. The genetic algorithm is employed strictly for design and not complete structural optimization. Dual band, five and six element switched parasitic antennas are presented. Lumped elemental loading along the radiators provide resonance and directed radiation at two GSM frequencies. Load value, radiator dimension and spacing are incorporated as design parameters. Experimentally built, 10dB return loss bandwidths of 17.2% and 9.6% and front to back ratios of 12.6dB and 8.4dB at 900MHz and 1900MHz respectively are measured. To reduce the ground requirements of monopole arrays, a skirted ground structure for switched parasitic antennas is analyzed. A six element switched parasitic monopole array with conductive ground skirt exhibits a front to back ratio of 10.7dB and main lobe gain of 6.4dBi at 1.575GHz. Radiation is not elevated despite lateral ground terminating at the parasitic elements. Skirt height is observed to linearly control radiation elevation, depressing the principal lobe through 40 degrees from 23 degrees above the horizontal. The Electronically Steerable Passive Array Radiator or ESPAR antenna is an adaptive parasitic monopole array. An ESPAR radiating structure incorporating a conductive ground skirt is designed for operation at 2.4GHz. Utility is confirmed with a frequency sensitivity analysis showing consistent electrical characteristics over an 8.1% bandwidth. The antenna design is improved with optimization to reduce average principal lobe elevation from 25 degrees to 9.7 degrees.

Switched and adaptive parasitic monopole array radiating structures are investigated. Antenna design is orientated toward increasing practicability for implementation in terrestrial wireless communication systems. A number of antennas are designed with the aid of optimization and commercial simulation software. Simulation procedure was verified with the experimental manufacture and measurement of the arrays. The antennas presented in this thesis comprise an active monopole surrounded by a ring of parasitic monopoles. Parasitic radiators are constructed with static loading to enable simple experimental realization. Beam positions of an electrically steered equivalent antenna are thus simulated. Antenna symmetry ensures the beam can be reproduced throughout the azimuth. Complex antenna geometries require antenna design through optimization. A genetic algorithm is employed with HFSS and NEC for electromagnetic analysis. The robust optimization method couples with simulation software flexibility to provide an effective design tool for arbitrary structures. The genetic algorithm is employed strictly for design and not complete structural optimization. Dual band, five and six element switched parasitic antennas are presented. Lumped elemental loading along the radiators provide resonance and directed radiation at two GSM frequencies. Load value, radiator dimension and spacing are incorporated as design parameters. Experimentally built, 10dB return loss bandwidths of 17.2% and 9.6% and front to back ratios of 12.6dB and 8.4dB at 900MHz and 1900MHz respectively are measured. To reduce the ground requirements of monopole arrays, a skirted ground structure for switched parasitic antennas is analyzed. A six element switched parasitic monopole array with conductive ground skirt exhibits a front to back ratio of 10.7dB and main lobe gain of 6.4dBi at 1.575GHz. Radiation is not elevated despite lateral ground terminating at the parasitic elements. Skirt height is observed to linearly control radiation elevation, depressing the principal lobe through 40 degrees from 23 degrees above the horizontal. The Electronically Steerable Passive Array Radiator or ESPAR antenna is an adaptive parasitic monopole array. An ESPAR radiating structure incorporating a conductive ground skirt is designed for operation at 2.4GHz. Utility is confirmed with a frequency sensitivity analysis showing consistent electrical characteristics over an 8.1% bandwidth. The antenna design is improved with optimization to reduce average principal lobe elevation from 25 degrees to 9.7 degrees.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Microelectronic Engineering
Full Text

Chez de nombreuses espèces de papillons, les adultes femelles relâchent d’infimes quantités de phéromones sexuelles pour attirer les mâles. Ces quantités sont de l’ordre de la dizaine de nanogrammes et les mâles peuvent les détecter à plusieurs centaines de mètres. Les mâles doivent donc être capables de sentir des concentrations de phéromone très faibles. Cette fonction olfactive est réalisée par les antennes et une des étapes critiques est la capture des molécules dans l’air. C’est un problème de transport de masse qui dépend étroitement de la forme de l’antenne. Une des formes les plus spectaculaires est l’antenne pectinée qui se retrouve dans plusieurs familles de papillons. Ce type d’antenne est aussi considéré plus efficace que les antennes cylindriques pour détecter les phéromones. Nous avons étudié comment la forme des antennes pectinées influence leur efficacité pour capturer les phéromones et nous nous sommes concentrés sur une espèce, Samia cynthia.Une antenne pectinée est un objet multi-échelle. Elle fait 1cm de long et est composée d’une branche principale, le flagellum, qui porte des branches secondaires, les ramis. Chaque rami porte de nombreux poils, les sensilles, qui font 150µm de long et 3µm de diamètre. Les dimensions caractéristiques de l’antenne couvrent donc 4 ordres de grandeur, ce qui rend l’étude des antennes difficile.Pour simplifier le problème, nous avons décomposé l’antenne en deux niveaux : la macrostructure, composée du flagellum et des ramis, et la microstructure, composée d’un rami et de sensilles qu’il porte. Chaque structure a été agrandie et construite par impression 3D. La construction des ramis et des sensilles, qui sont de longs et fins cylindres, a été un challenge.Les antennes pectinées sont des objets perméables, ainsi que les macro- et micro- structures. Ainsi, le flux d’air passe en partie à travers de tels objets et est en partie dévié. La perméabilité est la proportion du flux passant à travers l’objet. Ce paramètre est important car il détermine un limite haute de ce que peut capture l’antenne : les molécules du flux d’air dévié ne peuvent pas être capturées. Nous avons expérimentalement mesuré, par Vélocimétrie à Image de Particule, la perméabilité des macro- et micro- structures à différentes vitesses rencontrées par le papillon dans la nature.Nous avons ensuite calculé la capture de phéromone et l’efficacité de la microstructure en adaptant un modèle de transfert de chaleur à notre problème de transfert de masse. Nous avons montré que l’orientation longitudinale des sensilles est suffisante pour expliquer le phénomène de lentille olfactive qui dit que la partie distale de la sensille capture plus de molécules que la partie basale. Nous avons montré que l’efficacité de l’antenne est limitée par la perméabilité, qui augmente avec la vitesse de l’air, et par la capture locale, qui est la proportion de molécules capturée dans le flux passant à travers l’antenne et qui décroît avec la vitesse. Au final, la microstructure n’a pas un maximum d’efficacité autour d’une valeur de vitesse d’air mais elle est plutôt modérément efficace sur la large plage de vitesses d’air rencontrées par le papillon.Nous avons développé une méthode par le biais de simulations FEM pour combiner les deux niveaux (la macro- et la micro- structures). Cette méthode est basée sur la relation entre le traînée et la perméabilité et nous a permis de déterminer la perméabilité de l’antenne entière. Nous avons ensuite calculé l’efficacité d’une antenne pectinée et l’avons comparée à celle d’une antenne cylindrique. Nous avons trouvé que l’antenne pectinée est une bonne solution pour fortement augmenter la surface de contact entre l’air et l’antenne tout en maintenant une bonne efficacité de capture aux vitesses d’air rencontrées par le papillon
In many moth species, female adults release tiny amounts of sexual pheromone in order to attract male mates and reproduce. The quantity of released pheromone is around a few dozens of nanograms and male moths can detect it a few hundred meters away from females. As a consequence, they must be able to smell very low concentrations of pheromone. This olfactory function is carried out by the antennae. A critical step in the olfactory process is the capture of molecules from the air. This is a mass transport problem which depends heavily on the shape of the antenna. One of the most spectacular shapes, which occurs in several moth families, is the pectinate antenna. This type of antenna is also thought to be more effective at detecting pheromones than cylindrical-shaped ones. In this work, we investigated whether and how the shape of the pectinate antenna influences its efficiency at capturing pheromone molecules. We focused on one species, Samia cynthia.A pectinate antenna is a complex and multi-scale object. It has a length of 1cm and is composed of one main branch, the flagellum, which carries secondary branches, the rami. Each rami supports numerous hairs, the sensilla, which are 150µm long and have a diameter of only 3µm. Thus, the characteristic dimensions of the antenna span over four orders of magnitude, which makes the study of such objects difficult.To simplify our problem, we decided to split the pectinate antenna in two levels: the macrostructure, composed of the flagellum and the rami, and the microstructure, composed of a rami and the sensilla it bears. Both structures were scaled up and fabricated by Additive Manufacturing. The building of the rami and sensilla, which are long and thin cylinders, was a challenge as we reached the limits of the 3D-printers we used.Pectinate antenna are permeable objects, as are the macro-and microstructures. Thus, air flowing in the direction of such objects either passes through the antenna or is deflected around it. Leakiness if the proportion of flow passing through the permeable object. This parameter is important as it sets an upper limit on the pheromone captured by the antenna: molecules carried by the deflected part of the flow cannot be captured. We experimentally determined the leakiness of the macro- and microstructures at several air velocities encountered by a moth in nature using Particle Image Velocimetry.We then calculated the pheromone capture and efficiency of the microstructure by adapting a model of heat transfer to our mass transport problem. We showed that the longitudinal orientation of the sensilla is sufficient to explain the phenomenon of olfactory lens, stating that the tip of the sensilla captures more molecules than the base. We also found that the efficiency of the antenna is limited by both the leakiness of the antenna, which increases with air velocity, and the local capture, which is the proportion of molecules captured in the part of the airflow passing through the antenna and which decreases with air velocity. Eventually, the microstructure does not have a strong maximum efficiency at a specific air velocity but, instead, is moderately efficient over the large range of air velocity encountered by a moth.We developed a method with the help of FEM simulations to combine the two levels (the macrostructure and the microstructure). This method is based on the relation between drag and leakiness and allowed us to determine the leakiness of the entire antenna. We then could calculate the efficiency of the pectinate antenna and compared it with the one of a cylindrical-shaped one. We found that a pectinate design is a good solution to increase the surface contact between the air and the antenna strongly while maintaining a good capture efficiency at the velocities encountered by the moth

This dissertation evaluates the artificial neural technique for evolving a smart antenna system. The AI techniques pose a challenging research in the field of communication. As such the antennas help to communicate with the digital processor to choose the desired signals and reject the others. It makes its own decision even to find the level of interferences and noises to be discarded by amplitude elimination process through the use of perceptron optimization algorithms like LMS (Least Mean Squares). This method helps to enhance the performance of signal processing efficiently. The design of hardware and software are quite complex. This is due to the fact, that the behaviour of the system is not fully understood being a real-time dependent system. This research work is carried only on software with certain simulated activity on beam-formation algorithm and as well, the system responses before and after using the adaptive algorithm. In this report, we try to concentrate to work on the method of adaptivity to make antenna adaptable to a virtual form of real-time environment. For, this reason a two-element antenna is used for simulation testing, as it is the most commonly used antenna for all purposes in communication. It is also tested on various scanning levels of rotation to determine the learning rate (a parameter that has no effect on the radiation output after using LMS) mean-square error rates and convergence analysis. For the purpose of above mentioned tests, three hypotheses are framed in relation to side-lobe reduction level above 5 decibels, the narrowing of the beam after adaptivity and finally the response of the main beam output for varying values of learning rate, respectivelty. The given research work, may comprehend good practical use of this LMS algorithm and also to indicate antenna patterns and the responses to adaptivity conditions through clarity in graphical format.

The method is influenced to reduce computational complexity and bring simplicity to the functionality of the antenna with more efficient and effective adaptivness. An effort to test theoretical concepts in practice is also been made in this thesis work. The results show that the antenna system can be made to evolve itself through the process of adaptation with simple behaviour by relying on artificial intelligence technique which ensures little supervision and human intereference. Eventually, it is understood that the reader should have possessed prior concepts, related to antennas, digital signal processing and its practical usage in artificially intelligent systems and as well the exceptions in it, since the work is explained in the direct level assuming so.

Semiconductor based micro- and nano-structures grown in a systematic and controlled way using selective area growth are emerging as a promising route toward devices for integrated optical circuitry in optoelectronics and photonics field. This dissertation focuses on the experimental investigation of the nonlinear optical effects in selectively grown gallium nitride micro-pyramids that act as optical cavities, zinc oxide submicron rods and indium gallium nitride multiple quantum well core shell submicron tubes on the apex of GaN micro pyramids that act as optical antennae. Localized spatial excitation of these low dimensional semiconductor structures was optimized for nonlinear optical light (NLO) generation due to second harmonic generation (SHG) and multi-photon luminescence (MPL). The evolution of both processes are mapped along the symmetric axis of the individual structures for multiple fundamental input frequencies of light. Effects such as cavity formation of generated light, electron-hole plasma generation and coherent emission are observed. The efficiency and tunability of the frequency conversion that can be achieved in the individual structures of various geometries are estimated. By controlling the local excitation cross-section within the structures along with modulation of optical excitation intensity, the nonlinear optical process generated in these structures can be manipulated to generate coherent light in the UV-Blue region via SHG process or green emission via MPL process. The results show that these unique structures hold the potential to convert red input pulsed light into blue output pulsed light which is highly directional.

This contribution describes design, preparation and physico-chemical characterization of a new photo-stable hybrid antenna based on mesoporous SBA-15 silica. Concepts of host-guest chemistry are applied in such a way that one or more photoactive guest molecules are incorporated into the silica channels and on the outer surface, acting as energy harvesting and transferring units. The presented composite system be-haves as efficient Förster resonance energy transfer (FRET) pair and shows high photoluminescence and stability towards photodegradation, representing an important step forward in the search for new efficient materials with opto-electronic applications. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35498

Electroporation is a technique that employs electrical pulses to open pores in a cells membrane to allow DNA to enter and be transcribed using the cells machinery. A Bombyx mori odorant receptor (BmOr) promoter will be introduced to the antennae of Manduca sexta pupa using this technique. Vectors containing a BmOr promoter and TagRFP were constructed using pUC19 as the base plasmid by sequential ligations of first the promoter and then TagRFP using common restriction sites. After ligation the vectors were checked by restriction digest to extract and check the size of the insert and by sequencing the insert and comparing to the expected sequence. Vectors BmOR46-TagRFP-pUC19, BmOR41-TagRFP-pUC19, BmOR27-TagRFP-pUC19 were successfully created and are usable in electroporation experiments as demonstrated by successful electroporation of explanted antennal tissue. Future directions include use of GFP instead of TagRFP as the reporter gene and addition of RNAi to the vector to affect development through loss-of-function of a protein for the purpose of identifying some of the roles specific proteins play in olfactory development. Electroporation will be performed in live stage 4 pupa antenna instead of explants to allow for development of the antenna after introduction of the vector.

Im Rahmen der Dichtematrixtheorie wurde die dissipative Exzitonendynamik in photosynthetischen Pigment--Protein-- Komplexen untersucht. Es konnten zwei verschiedene Modelle entwickelt werden. In einem ersten Effektivmoden--Modell wird eine Kopplung der Pigmente an eine effektive Proteinmode pro Pigment behandelt. Die volle Quantendynamik der effektiven Moden findet Ber\"ucksichtigung. Auf diese Weise ist das Modell in der Lage, koh\"arente Kerndynamik und Ged\"achtnisseffek te in der Exziton--Schwingungswechselwirkung zu beschreiben. Diese Effekte treten in einer st\"ohrungstheoretischen Beschreibung in Form von Ged\"achtnisintegralen in den Bewegungsgleichungen f\"ur die dynamischen Variablen auf und werden oft im Rahmen einer {\it Markov} N\"aherung vernachl\"assigt. In einer nichtst\"ohrungstheoretischen Behandlung der Exziton--Schwingungswechselwirkung sind {\it nicht--Markov} Effekte nat\"urlicherweise enthalten. Die restlichen niederfrequenten Schwingungsmoden der Proteine und h\"oherfrequenten intramolekularen Moden der Pigmente werden als W\"armebad behandelt. Die Kopplung der Pigmente und effektiven Proteinmoden an das W\"armebad wird st\"ohrungstheoretisch (in zweiter Ordnung)beschrieben. Diese Wechselwirkung umfa\ss t(i) eine D\"ampfung der Dynamik der effektiven Moden, (ii) die Modulation der {\it Coulomb}--Wechselwirkung zwischen den Pigmenten und (iii) interne Konversion zwischen den h\"oherangeregten $S_n$--Zust\"anden und den ersten angeregten Singlet $S_1$--Zust\"anden der Pigmente. In einem zweiten sogenannten Multimoden--Modell wurde die gesamte Exziton-- Schwingungswechselwirkung st\"ohrungstheoretisch behandelt, und die Standard {\it Redfield}--Theorie fand Anwendung in der Darstellung der Multiexzitoneneigenzust\ "ande. In diesem Modell l\"a\ss t sich Exzitonenrelaxation durch die kopplungsgewichtete Zustandsdichte (sogenannte Spektraldichte) der niederfrequenten Proteinmoden, welche ein W\"armebad bilden, beschreiben. Die Standard {\it Redfield}--Theorie wurde bereits in \cite{Kueh97} auf einen anderen Pigment--Protein Komplex (LH-2) angewendet. Das Neue an dem hiergew\"ahlten Zugang besteht in der Formulierung eines Korrelationsradius der Proteinschwingungen. Dieser gibt an wie die Kopplungen unterschiedlicher Pigmente an ihre lokalen Proteinumgebungen korreliert sind. Die Multiexzitonenspektraldichte der Proteine kann mittels des Korrelationsradius auf molekulare Spektraldichten der lokalen Kopplungen der Pigmente zur\"uckgef\"uhrt werden. Diese wurden f\"ur alle Pigmente als gleich angenommen, und die Theorie wurde so formuliert, da\ss{} Exzitonenrelaxation zu einer Globalanalyse der Spektraldichte der Proteinschwingungen benutzt werden kann. F\"ur die numerische Behandlung konnte eine effiziente Propagationsmethode der Dichte\-matrix entwickelt werden. Diese gestattet eine nichtst\"ohrungstheoretische Behandlung externer Felder und eine Unterscheidung der verschiedenen r\"aumlichen Anteile der lichtinduzierten Polarisationswelle. Dies wurde durch eine Entwicklung der Dichtematrix nach den Tr\"agerwellen der externen Felder erreicht. Die hohe Effizienz dieser Methode beruht auf der Abwesenheit der hochfrequenten Anteile der externen Felder. Lediglich die Einh\"ullenden der Lichtfelder treten in den Bewegungsgleichungen f\"ur die Entwicklungskoeffizienten der Dichtematrix auf. Diese Methode gestattete es bis zu 9 elektronische Zust\"ande gekoppelt an zwei effektive Moden zu ber\"ucksichtigen. Bislang konnten in der Literatur lediglich Modelle mit bis zu 3 elektronischen Zust\"anden und zwei effektiven Moden behandelt werden \cite{Matr95}. Die ultraschnelle Exziton--Schwingungs--Dynamik in einem Chl{\it a/b} Heterodimer des Lichtsammelkomplexes LHC-II gr\"uner Pflanzen wurde im Effektivmoden--Modell untersucht. Aus der Simulation der zweifarbigen Pump--Test--Spektren von \cite{Bitt94} konnten Schlu\ss folgerungen zur Lage der optischen \"Ubergangsdipolmomente des Chl{\it a} und des Chl{\it b} Pigments (welche bei 680 nm und 650 nm absorbieren) getroffen werden. Die Dipole sind eher in {\it in line} als in {\it sandwich} Geometrie angeordnet. Die gemessene Femtosekunden Komponente im Pump--Test--Signal kann auf die, durch die {\it Coulomb}--Wechselwirkung induzierte, Umverteilung der Oszillatorst\"arke innerhalb der Ein-- und Zwei--Exzitonen\"uberg\"ange zur\"uchgef\"uhrt werden. Durch die Einbeziehung h\"oherangeregter Singlet $S_n$--Zust\"ande der Pigmente und interner--Konversionsproz esse zwischen diesen und den $S_1$--Zust\"anden war eine mikroskopische Beschreibung von Exziton--Exziton Annihilation m\"oglich. Im Rahmen dieser Beschreibung konnten die intensit\"atsabh\"angigen zweifarbigen Pump--Test--Spektren von \cite{Bitt94} simuliert werden. Die Simulation ergab eine interne Konversionsrate $1/R^{(\rm IC)}_{S_n\rightarrow S_1}=2.2$ ps und ein Verh\"altnis der Dipolmomente der Pigmente $\mu_{S_1\rightarrow S_n}/\mu_{S_0 \rightarrow S_1}=$1.19. Mit einem einheitlichen Parametersatz konnten neben den zweifarbigen Pump--Test--Spektren auch die 77 K einfarbigen Pump--Test--Spektren von \cite{Viss96}erfolgreich simuliert werden.Wiederum erkl\"art die Umverteilung der Oszillatorst\"arke durch die {\it Coulomb}--Wechselwirkung den Verlauf des gemessenen Signals. Nach etwa 2 ps \"andert dieses sein Vorzeichen. In dieser Zeit findet die Exzitonenrelaxation zwischen dem hochenergetischen und dem niederenergetischen Ein--Exzitonenniveau des Dimers statt und von diesem wird ein Zwei--Exzitonen\"ubergang mit hoher Oszillatorst\"arke m\"oglich.Um den Einflu\ss{} von intramolekularer angeregter Zustandsabsorption zu untersuchen, wurde der h\"oherangeregte $S_n$--Zustand von Chl{\it a} energetisch in Resonanz zum Testpuls gebracht. Eine zus\"atzliche Umverteilung von Oszillatorst\"arke unter den Zwei--Exzitonen\"uberg\"angen wurde gefunden. Der Haupteffekt tritt jedoch schon bei Ber\"ucksichtigung von zwei elektronische Zust\"anden pro Pigment auf. Schlie\ss lich konnte gezeigt werden, da\ss{}, falls die effektiven Moden ebenfalls st\"ohrungstheoretisch (im Rahmen des W\"armebades) behandelt werden, die Berechnung der Pump--Test--Signale signifikant schlechtere \"Ubereinstimmung mit den gemessenen Daten ergibt. Es konnte lediglich \"Ubereinstimmung auf einer Femtosekunden-- oder einer Pikosekundenzeitskala erreicht werden. F\"ur eine konsistente Beschreibung \"uber den gesamten Zeitverlauf hinweg, m\"ussen Ged\"achtniseffekte in der Exziton--Schwingungswechselwirkung Ber\"ucksichtigung finden. Es gilt jedoch zu beachten, da\ss{} die Wechselwirkung des Chl{\it a/b} Dimers mit den restlichen Pigmenten des LHC-II Monomers vernachl\"assigt wurde. Deshalb w\"are es sehr aufschlu\ss reich die im Rahmen des Effektivmoden--Modells erzielten Resultate, mit einem Multimodenzugang unter Ber\"ucksichtigung aller 12 Pigmente des LHC-II Monomers zu vergleichen. Eine Hauptschwierigkeit bei diesem Vorgehen stellt die Unkenntnis der genauen Geometrie der optischen \"Ubergangsdipolmomente der Pigmente im LHC-II dar. Deshalb ist es schwierig die {\it Coulomb}--Wechselwirkung zwischen den Pigmenten abzusch\"atzen. Erste Absch\"atzungen der Dipolgeometrien der Chl{\it a} Pigmente wurden k\"urzlich in \cite{Guel97} ver\"offentlicht. Man k\"onnte diese Absch\"atzungen, mit den hier erzielten Ergebnissen kombinieren. Die Chl{\it b} Dipole m\"u\ss ten demnach so orientiert werden, da\ss{} in den Chl{\it a/b} Dimeren {\it inline} Geometrie vorliegt. Jedoch k\"onnen erste Simulationen im Multimoden-Modell diesen Ansatz bis jetzt nicht best\"atigen. F\"ur den bakteriellen FMO--Komplex erlaubte die Strukturanalyse die Angabe der optischen \"Ubergangsdipolmomente der 7 Bakteriochlorophylle \cite{Tron85,Li97}. Im Standardzugang der Simulation linearer Spektren von FMO-Komplexen wurden die homogenen Linienbreiten der Exzitonen\"uberg\"ange stets vernachl\"assigt \cite{Pear92,Pear93,guelen97,Louw97}. Im Rahmen der vorliegenden Arbeit konnte ein mikroskopisches Modell der Exzitonenrelaxation, formuliert im Multimoden--Modell, zur Berechnung realistischer homogener Exzitonen--Linienbreiten benutzt werden. Die verwendete Dichtematrixtheorie erlaubte dar\"uberhinaus auch die Simulation der Temperaturabh\"angigkeit optischer Spektren.So war ein simultaner Fit der linearen Absorption, gemessen in \cite{Frei97}, bei zwei verschiedenen Temperaturen essentiell, um den richtigen mikroskopischen Parametersatz zu finden. Dieser Parametersatz, welcher nachher in der Simulation von nichtlinearen zeitaufgel\"osten Pump--Test--Signalen verifiziert werden konnte, umfa\ss t die lokalen sogenannten {\it site} Energien der 7 BChl Molek\"ule, die globale Form der Spektraldichte der Proteinschwingungen und den Korrelationsradius der Exziton--Schwingungswechselwirkung. F\"ur letzteren wurde der Wert $R_c=21 \AA$ bestimmt, welcher zwischen kleinsten (11\AA) und gr\"o\ss ten (30 \AA) Pigmentabst\"anden im FMO--Monomer liegt. Somit kann die Kopplung der Proteinschwingungen an verschiedene Pigmente als teilkorreliert bezeichnet werden. Die Abh\"angigkeit der Exzitonenrelaxation und der linearen Absorptionsspektren von $R_c$ wurde untersucht. Als genereller Trend zeigte sich, da\ss{} die Exzitonenrelaxation umso schneller verl\"auft, je kleiner der Korrelationsradius ist. Mit demselben Zugang und denselben Parametern konnten in der Folge ultraschnelle zweifarbige Pump--Test--Experimente, durchgef\"uhrt von \cite{Frei97} bei 20 K, erfolgreich simuliert werden. Die gute \"Ubereinstimmung mit den gemessenen Daten bei den verschiedenen Testwellenl\"angen erlaubt es, die St\"arke der intramolekularen angeregten Zustandsabsorption der Pigmente im FMO--Protein abzusch\"atzen. Ein Verh\"altnis $\mu_{S_1\rightarrow S_n}/\mu_{S_0\rightarrow S_1}=0.5$ der optischen \"Ubergangsdipolmomente ergab den besten Fit. Dieser Parameter war der einzigste, der nicht aus den linearen Spektren ermittelt werden konnte, da er lediglich in nichtlinearen optischen Experimenten auftritt. Eine genauere Pr\"ufung der Pump--Test--Simulationen ergibt Abweichungen von den gemessenen Daten f\"ur kleine Verz\"ogerungszeiten ($
The dissipative dynamics of excitons in photosynthetic pigment--protein--complexes has been investigated in the framework of the density matrix theory. Two different model pigment--protein--complex Hamiltonians could be developed. In a first so called effective mode model the local coupling of the pigments to one effective protein mode per pigment has been considered. The full quantum motion of these effective modes was taken into account. In this way the model is capable to describe coherent nuclear motion and also memory effects in the exciton--vibrational interaction. The latter usually appear in a perturbation theory with respect to the exciton--vibrational interaction as memory integrals in the equation of motion for the dynamic variables. And often, a Markov approximation is applied, i.e. memory effects are neglected. In a non--pertubative treatment of the coupling between excitons and effective protein modes non-Markovian effects are of course included. The remaining low frequency modes of the protein and high frequency intramolecular modes of the pigments were treated as a heat bath. The coupling of pigments and effective protein modes to the heat bath was described in second order perturbation theory. This coupling includes (i) a damping of the motion of the effective modes, (ii) a modulating of the inter pigment {\it Coulomb} interactions, and (iii) internal conversion transitions between the higher excited singlet $S_n$--states and the first excited $S_1$--states of the pigments. The coupling to external light fields as well as the inter--pigment Coulomb interaction are included non--pertubatively. A microscopic description of exciton--exciton annihilation processes could be offered, which together with the non--pertubative inclusion of external fields allows to simulate the intensity dependence of non--linear optical spectra. In a second so called multi--mode model the whole exciton--vibrational interaction was described in second order perturbation theory, and the standard Redfield theory was applied in the representation of multi--exciton eigenstates of the pigment--protein--complex. Exciton relaxation in this model is characterized by the coupling weighted density of states (so called spectral density) of the low frequency protein vibrations, which form a multi--mode heat bath. The standard multi--level Redfield theory has been applied also in \cite{Kueh97} on another pigment--protein complex (LH-2). However, what is new in the present approach is the formulation of a correlation radius of protein vibrations. It enables one to charaterize how the couplings of different pigments with their local protein environments are correlated. The multi--exciton spectral density of the protein vibrations can be discussed in terms of the correlation radius and molecular spectral densities characterizing the local coupling of pigments and proteins. These spectral densities have been taken equal for all pigments, and the theory was formulated in such a way that exciton relaxation could be used for a global shape analysis of the spectral density of protein vibrations. An efficient propagation scheme for the density matrix could be developed. It allows for an exact inclusion of external fields and for a distinction of the different spatial contributions of the light induced polarization wave. An expansion of the density matrix with respect to the carrier waves of the external light fields has been carried out. The high efficiency of this method is due to the absence of the high frequency part of the external fields. Instead only the envelopes of the external fields enter the equation of motion for the expansion coefficients of the reduced density matrix. This efficient propagation scheme allowed for the treatment of up to 9 electronic states including two effective modes. Up to now in the literature a 3 electronic state system with two effective modes could be investigated \cite{Matr95}. The ultrafast exciton--vibrational dynamic in a Chla/b hetero dimer of the light--harvesting complex LHC-II of green plants has been studied within the effective mode model. From the simulation of the two--color pump--probe spectra of \cite{Bitt94} evidence could be obtained for the geometry of the optical transition dipoles of the Chla and Chlb pigments absorbing at 680 nm and 650 nm, respectively. They are arranged rather in line than like a sandwich. The measured femtosecond component in the pump--probe signal reflects the Coulomb interaction induced redistribution of oscillator strength among the one-- and the two--exciton transitions of the dimer. Changing the dipole geometry resulted in a qualitative change of the signal. The inclusion of higher excited singlet $S_n$--states of the pigments and internal conversion transitions to the first excited singlet $S_1$--states allowed for a microscopic description of exciton--exciton annihilation. Within this model the intensity dependence of the two--color pump--probe signal measured in \cite{Bitt94} could be simulated, revealing an inverse internal conversion rate of $1/R^{(\rm IC)}_{S_n\rightarrow S_1}=2.2$ ps, and a ratio of dipole moments $\mu_{S_1\rightarrow S_n}/\mu_{S_0\rightarrow S_1}=$1.19. The energy of the $S_n$--state has been taken twice the $S_1$--state energy for both pigments. Consistently to the simulation of the two--color pump--probe experiments also the 77 K one--color pump--probe experiment of \cite{Viss96} could be successfully simulated. It could be demonstrated that again the redistribution of oscillator strength by the {\it Coulomb}interaction can explain the observed switch of the sign of the signal after about 2 ps. In this time exciton relaxation between the high-- and the low energetic exciton states of the dimer occurs and a two exciton transition starting from the low energetic one exciton state becomes possible. To look for an influence of intramolecular excited state absorption of the pigments the higher excited $S_n$--state of Chl{\it a} has been shifted to reach resonance with the probe pulse. A further redistribution of oscillator strength among the two exciton states could be found. However, the principle effect is already included if only interacting two--level molecules are considered. Finally it could be demonstrated that if the effective modes are shifted into the heat bath, the simulation of the one-- and two--color pump--probe experiments gives significantly worse results. Such a simplified approach corresponds to the multi--mode model applied afterwards on the FMO--complex. Only the behavior on the femtosecond or the picosecond time scale could be understood within the simple model. For a consistent description over the whole time range memory effects in the exciton--vibrational interaction had to be taken into account. However the interaction of the Chl{\it a/b} dimer with the remaining pigments in the LHC-II monomer have been neglected. Therefore it would be interesting to compare the dimer results within the effective mode model with a multi --mode approach including all 12 pigments of the LHC-II monomer. A major difficulty arises from the fact that the geometry of the optical transition dipoles of the pigments in the LHC-II has not been resolved yet. Therefore it is difficult to estimate the mutual {\it Coulomb} interactions between the pigments. However, a promising result has been published recently in \cite{Guel97} giving estimates for the dipole geometries of the Chl{\it a} molecules. It is tempting to combine these results with the result of this work and arrange the remaining Chl{\it b} transition dipoles in such a way that within the Chl{\it a/b} dimers {\it in li ne} geometry is obtained. However first calculations up to now do not give such a consistent fit of the one-- and two-- color pump--probe experiments as it could be obtained within the effective mode model. Further work is in progress. For the bacterial light harvesting FMO complex a high resolution structural investigation allowed to give the geometry of the $Q_y$ transition dipoles of the 7 BChls \cite{Tron85,Li97}. In the standard approaches \cite{Pear92,Pear93,guelen97,Louw97} of the simulation of the linear response of FMO--complexes the homogeneous line width has been always neglected. In this work, a microscopic model of exciton relaxation formulated in the multi--mode model could be used to calculate realistic homogeneous exciton transition line shapes. Moreover, since temperature enters the density matrix theory, it was possible to simulate the temperature dependends of the spectra measured in \cite{Frei97}. A simultaneous fit of the linear absorption at two different temperatures was essential for getting the right microscopic parameter set which could be verified afterwards in the simulation of non--linear optical experiments in the time domain. These parameters include the site energies of the 7 BChl molecules, the global shape of the spectral density of protein vibrations, and the correlation radius of exciton--vibrational coupling. For the latter a value $R_c=$ 21 \AA{} could be obtained, which lies in the middle between smallest (11\AA) and largest (30\AA) center to center distances of pigments in the FMO monomer. Hence the coupling of the protein vibrations to different pigments can be characterized as partly correlated. The dependence of the exciton dynamics and linear absorption spectra on $R_c$ was investigated, and as a general trend it could be obtained that a small correlation radius enhances exciton relaxation. Using the same approach and the same parameters ultrafast pump--probe experiments of \cite{Frei97} performed at 20 K could be successfully simulated at three different probe wavelengths. The nice agreement with the measured data did allow for an estimation of the intramolecular excited state absorption of the pigments in the FMO protein. A ratio of dipole moments $\mu_{S_1\rightarrow S_n}/\mu_{S_0\rightarrow S_1}=0.5$ was obtained. This was the only parameter, which could not be determined from the linear absorption fit, since it appears only in the non--linear optical response. A closer examination of the pump--probe simulations revealed some deviations from the measured data for small delay times ($

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2012.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 135-143).
The detection of gravitational waves (GWs) from astrophysical sources shows promise as a new method to probe extremely energetic phenomena and test the strong field limit of the general theory of relativity. The era of the first generation of broadband interferometric GW antennae is now drawing to a close, and the construction of the second generation has begun. The Laser Interferometer Gravitational-wave Observatory (LIGO) in the United States is one component of a worldwide array of sites designed to collectively record and analyze these GW signals. In preparation for the next major phase of operation, named Advanced LIGO, an incremental upgrade and prototyping project known as Enhanced LIGO introduced several upgrades to the initial LIGO detectors. The addition of the output mode cleaner (OMC), a critically coupled optical cavity designed to filter undesired light from the output of the interferometer before the GW signal is sensed on a photodetector, was one of these upgrades. This work describes several lessons learned as a result of the installation and commissioning of the OMC in Enhanced LIGO. The techniques described in this thesis include the development of a novel OMC alignment system designed to maximally transmit the GW signal in the presence of contamination that would confound a typical automatic alignment system, a design for a remotely controllable automatic mode matching system for the OMC, and prescriptions for reducing the presence of beam jitter noise associated with the OMC. The designs of each of the future GW detectors include the use of an OMC, thus the techniques described in this thesis will be directly applicable to achieving the maximum sensitivity of these detectors.
by Nicolás de Mateo Smith-Lefebvre.
Ph.D.

Le travail de thèse a été réalisée dans le cadre du projet ANR «Stick’It» visant à développer de nouvelles technologies peu coûteuses et innovantes dédiées à la conception de composants radiofréquences (RF) 2D, 2,5D et 3D, notamment des antennes imprimées sur des matériaux conformes. Les applications ciblées sont principalement des appareils de réseaux domestique, tels que les décodeurs, dont les formes et les dimensions sont très variées. Par conséquent, il est nécessaire de concevoir des antennes sur des substrats souples.Selon nos besoins pour un matériau de substrat flexible, peu coûteux, avec de bonnes propriétés RF, la capacité de recyclage et en particulier la capacité à fabriquer des structures 3D, après avoir étudié différents matériaux diélectriques pour l’électronique flexible, le papier s'est trouvé le plus adapté.Les travaux de cette thèse se sont déroulés en trois phases.Dans la première phase, c'était l'étude des méthodes de caractérisation des matériaux pour obtenir leurs propriétés électromagnétiques. Après l'analyse, la méthode de perturbation utilisant une cavité cylindrique a été choisie pour la caractérisation du papier. Les premiers résultats de ce processus ont été vérifiés en réalisant et en testant des antennes simples telles que des monopoles alimentés par CPW sur du papier et du PET. Ensuite, la mesure du papier E4D a été effectuée avec 50 échantillons découpés dans différentes feuilles de papier E4D de trois épaisseurs différentes, 104 m, 210 m et 387 m. Les résultats ont été analysés statistiquement et ont donné r = 3.184, tan = 0.092. Les dispersions des résultats mesurés à 2,5 GHz sont 0.25% pour r et 0.26% pour tan. Ces résultats ont été utilisés pour la phase suivante.Au cours de la deuxième phase, les antennes différentes ont été conçues sur le papier E4D d'épaisseur 0,104 mm et 0,21 mm, notamment des IFA, des antennes SIW et des antennes monopoles alimentées par une ligne microruban. Les prototypes ont été réalisés à l'aide d'une technique de sérigraphie et testés pour déterminer les propriétés de l'adaptation et les diagrammes de rayonnement.Dans la troisième phase, les antennes proposées ont été étudiées dans des conditions d'emballage réalistes, où un boîtier décodeur était en plastique ABS avec différentes dimensions. Le premier cas concernait deux antennes MIMO placées orthogonalement dans des boîtiers ABS différents, avec un espace suffisant pour que les deux puissent rester plats. Le second cas était une boîte à hauteur limitée, de sorte qu’au moins une des antennes doit être pliée.Ainsi, une étude de l'effet de flexion a été réalisée, tout d'abord avec un simple dipôle droit et un monopole droit sur le papier E4D, puis avec une antenne à large bande proposée dans la seconde phase. L’étude a montré que la flexion n’affecte pas beaucoup l’adaptation de l’antenne sur une large bande de fréquences. Cependant, ses diagrammes de rayonnement tournent dans le plan E avec un angle de rotation dépendant de la position de pliage et de l'angle de flexion.Ensuite, le système MIMO de deux antennes placé orthogonalement dans un boîtier ABS de hauteur limitée, de sorte qu’une antenne doit être pliée et une autre reste plate. Dans tous les cas de système d'antenne MIMO, nous avons obtenu une bonne isolation (> 20 dB) et un coefficient de corrélation (ECC) inférieur à 0,05
The thesis was carried out within the ANR project « Stick’It » that aimed at developing new, low-cost and innovative technologies devoted to the design of 2D, 2,5D and 3D radiofrequency (RF) components including antennas printed on conformable materials. The targeted applications are primarily home-networking devices such as set-top boxes where their forms and dimensions are widely varied. Therefore, it is necessary to design antennas on flexible substrates.According to our needs for a substrate material that is flexible, low cost, with good RF properties, recycling ability, and especially ability to make 3D structures, after considering various dielectric materials for flexible electronics, paper substrate appeared to be the most suitable for our purpose.The work of this thesis conducted in three phases.In the first phase, it was the study of methods for characterization of materials to obtain their electromagnetic properties. After analysis, the method of perturbation using a cylindrical cavity was chosen for characterization of paper. The first results of this process were verified by realization and testing of simple antennas such as CPW-fed monopoles on paper and PET. Then, the measurement of E4D paper substrate was performed with 50 samples cut from various E4D paper sheets of three different thicknesses, 104 m, 210 m and 387 m. The results were analyzed statistically and gave r = 3.184, tan = 0.092.The dispersions of the results measured at 2.5 GHz are 0.25% for r and 0.26% for tan. These results were used for the next phase.In the second phase, different antennas were designed on 0.104-mm and 0.21-mm thick E4D paper including IFAs, SIW cavity-back antenna and microstrip-fed wideband monopole antennas. The prototypes were realized using screen printing technique and tested for matching property and radiation patterns.In the third phase the proposed antennas were studied in realistic package conditions, where a set-top box was made of ABS plastic with different dimensions. The first case was with two MIMO antennas orthogonally located in different ABS boxes with sufficient space, so that both of them can remain flat. The second case was a box with a restricted height, so that at least one of the antennas needs to be bent.Thus, a study of bending effect was carried out, first of all, with a simple straight dipole and a straight monopole on E4D paper, then with a wideband antenna proposed in the second phase. The study showed, that bending does not much affect the matching of the antenna over a wide frequency band. However, its radiation patterns rotate in the E-plane with a rotation angle depending on the bending location and bending angle.Then, the MIMO system of two antennas placed orthogonally in an ABS box with restricted height so that one antenna needed to be bent and another remained flat. In all cases of MIMO antenna system, we obtained good isolation (>20 dB) and Envelope Correlation Coefficient (ECC) less than 0.05

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2004.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (leaves 203-215).
Around the world, efforts are underway to commission several kilometer-scale laser interferometers to detect gravitational radiation. In the United States, there are two collocated interferometers in Hanford, Washington and one interferometer in Livingston, Louisiana. Together, these three interferometers form the Laser Interferometric Gravitational-wave Observatory (LIGO). The core of the work described in this thesis is the modeling and reduction of the noise in the interferometers which limits their ultimate sensitivity. A vital component of the noise reduction is the modeling, design, and implementation of [approximately]100 feedback control systems. The most critical of these systems are described and motivated. Although improvements are continuously being made to the stability and noise character of these detectors, several months of data have been collected. Various efforts are underway to search through these data for gravitational wave signals. Included here, is a description of a search made through the data for signals from the ringdown of the quasi-normal modes of Kerr black holes. In addition, several possible future improvements to the detectors are outlined.
by Rana Adhikari.
Ph.D.

Cette thèse porte sur des matériaux luminescents sulfurés, notamment des astérisques moléculaires persulfurés phosphorescents, basés sur l'hexakis(p-tolylthio)benzène (HTTB), et d'un thiosphérulène (balle moléculaire soufrée). Non émissif en solution, HTTB est un des émetteurs phosphorescents les plus puissants à l'état solide, avec une émission induite par agrégation (AIE). Un des objectifs est de synthétiser des dérivés portant des acides carboxyliques en périphérie pour augmenter la solubilité aqueuse et mettre à profit la coordination sélective d'ions Pb(II) et Cd(II) afin de former des édifices supramoléculaires rigides luminescents et des capteurs intelligents. Ces fonctions permettent d’ancrer les astérisques à l'intérieur de nanoparticules de silice (NPs) pour activer la phosphorescence. Ces nouvelles NPs, dont l’émission est sensible à l’oxygène, sont un colorant pour l'imagerie in vivo par microscopie à deux photons d'excitation
This thesis focuses on sulfurated luminescent materials, including phosphorescent persulfurated molecular asterisks, based on hexakis(p-tolylthio) benzene (HTTB), and a thiospherulene (a sulfurated molecular ball). Non-emissive in solution, HTTB is one of the most powerful phosphorescent emitters in the solid state, from an aggregation-induced emission (AIE). One of the objectives is to synthesize some asterisk derivatives bearing carboxylic acids at their periphery to increase their aqueous solubility, and to take advantage of the selective coordination of Pb (II) and Cd (II) ions in order to form luminescent rigid supramolecular edifices and intelligent sensors. These functions allow to anchor the asterisks inside some silica nanoparticles (NPs) to activate phosphorescence. These new NPs, whose emission is sensitive to oxygen, are dyes for in vivo imaging by two-photon excitation microscopy

Les antennes microruban et en particulier l’antenne microruban rectangulaire sont étudiées et utilisées depuis plusieurs dizaines d’années.

Comme pour toute antenne, il est important de disposer pour ces antennes d’un modèle analytique qui permette une bonne compréhension du fonctionnement et fournisse de manière rapide des valeurs pour les principaux paramètres (fréquence de travail, impédance, gain, rendement et bande passante).

Au fil des ans, deux modèles, chacun comprenant de nombreuses variantes, ont été développés :le modèle dit « de la ligne de transmission » et le modèle dit « de la cavité ». Ces modèles sont soit peu rigoureux, soit complexes et donnent souvent des résultats assez éloignés de la réalité.

L’objectif de ce travail est double :définir un modèle qui soit d’une part aussi simple et direct que possible et d’autre part aussi précis que possible.

Le premier objectif est atteint dans la mesure où on n’utilise que la loi fondamentale du rayonnement des courants réels (électriques) en excluant tout recours à des courants virtuels (magnétiques).

Concernant l’objectif de précision, des comparaisons nombreuses avec des résultats d’un simulateur purement numérique et des mesures indiquent une amélioration pour tous les paramètres mais en particulier pour l’impédance qui est le point faible de tous les modèles existants.

Microstrip antennas and the rectangular microstrip antenna in particular have been studied and used for several decades.

As every antenna, the microstrip antenna requires a good analytical model that provides physical insight and an easy prediction of the antenna parameters (resonance frequency, impedance, gain, efficiency and bandwidth).

Over the years, two families of models have been developed, each involving many variants: the “transmission line” and the “cavity” models. These models either lack accuracy or are very complex and produce results that may be far away from reality.

The objective of this work is double: defining a model as simple and direct as possible and on the other hand as accurate as possible.

The first objective has been reached as all our calculations rest on the fundamental radiation formula by real (electrical) currents excluding any virtual (magnetic) currents.

Regarding accuracy, comparisons to numerical simulations and measurements show an improvement, in particular with regard to the prediction of the impedance parameters, which is the weak point of all existing models.

Doctorat en Sciences de l'ingénieur
info:eu-repo/semantics/nonPublished

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada
An agile RF routing system has been developed which utilizes phasing techniques to direct signal power to any one of four orthogonally mounted antennae, or either set of two antennae mounted 180° apart on a launch vehicle. The system has been integrated into a telemetry transmitter and has shown superior performance to traditional methods of antennae switching. The unit is self-correcting to maintain maximum RF power at the desired antenna port(s) across a dynamic mission environment. Due to its low loss and high reliability, this method of antennae switching provides a robust RF link.

Afin de répondre à la demande croissante de nouveaux services, les objets que nous utilisons au quotidien (les smartphones, les voitures, les avions, etc.) tendent à intégrer de plus en plus de systèmes radio tandis que l’espace disponible pour l’intégration de ces éléments est de plus en plus réduit. Ces systèmes radio nécessitent l’utilisation de plusieurs antennes devant répondre à des critères de compacité, d’isolation, de coût, etc. À titre d’illustration, un smartphone contient plusieurs antennes pour assurer des fonctions telles que la téléphonie, la navigation, la connexion à internet par WiFi, les liaisons Bluetooth, la technologie NFC (Near-Field Communications) et ce nombre tend à s’accroitre considérablement avec l’émergence de nouveaux services. Le même phénomène se retrouve également au niveau des plateformes aéroportées où des fonctions telles que la communication, la navigation, le radar, etc. sont utilisées. Cela conduit donc à la nécessité de réduire le nombre d’antennes en regroupant par exemple plusieurs fonctions au sein d’une même et unique antenne. Dans de précédents travaux de recherches, J. Euzière a démontré la possibilité de combiner une fonction radar et une seconde fonction (ici de communication) en utilisant un réseau de 16 monopoles initialement dédié au seul radar, grâce au Time Modulated Array (TMA). De cette façon, les deux fonctions utilisaient la même fréquence et étaient alimentées par une seule source. L’objectif principal de cette thèse est de proposer une solution d’antenne multifonction pour radar et communication encore plus compacte (constituée d’une seule antenne). L’idée est de partir d’une solution antennaire déjà existante et d’y apporter les modifications nécessaires à l’ajout d’une seconde fonction, sans pour autant augmenter la surface de l’antenne ni la complexité du système
In order to respond to the increasingly demand of new services, the objects we use on a daily basis (such as mobile phones, cars, airplanes etc.), tend to integrate more and more radio systems while the space available is limited. These radio systems require the use of many antennas that must meet multiple requirements such as compactness, isolation, costs, etc. A smart-phone, for example, contains several antennas for global navigation satellite system (GNSS), WiFi, TV, FM radio, Bluetooth, near-field communications (NFC) and the number is expected to increase as new systems are added. Another example is in airborne platforms where multiple functions such as communication, navigation, radar, electronic warfare are used. This leads to the need of reducing the number of associated antennas by regrouping several radio functions into a single antenna. However, combining the functionality of several antennas into one shared radiating element while maintaining the functionality of the various radio systems presents a great challenge. During its Ph.D, J. Euzière demonstrated the possibility to combine a radar function and a secondary function from a 16-monopole array originally dedicated to radar operation by using Time Modulated Array (TMA) technique. By this way, the two functions were operating at the same frequency and the system was powered by a single source.The main objective of this thesis is to propose a more compact antenna (a single antenna) dedicated to radar and communication operations instead of using antenna array as J. Euzière did it. The idea is to start from an existing antenna solution and make the necessary modifications to add a second function without adding additional surface and complexity. As we are interested in radar applications, we will choose a directive antenna: a horn antenna. The goal is then to study the possibility to modify the radiation pattern of the horn antenna through controllable elements (slots) and to transmit a direct modulated signal at the antenna level for the communication function. Furthermore, polarization diversity is an attractive way to increase the isolation between two applications. Thus, this aspect will be taken into account in the design of the antenna solution

Les avions comportent plusieurs systèmes de navigation et de communication nécessitent des antennes VHF large bande. Réduire la taille de ses antennes est un enjeu majeur tout en gardant des bonnes performances. Cette thèse propose des nouvelles configurations d'antennes à profil bas utilisant des nouveaux matériaux nanocomposites non conducteurs constitués de nanoparticules magnétiques développés au Lab-STICC. Un monopole planaire large bande a été développé et optimisé avec un taux de miniaturisation de 60% grâce à l'utilisation d'un matériau magnéto-diélectrique de forte perméabilité et faible pertes couvrant seulement 5% de sa surface. Les résultats expérimentaux, en presque parfait accord avec les simulations, montrent que le diagramme de rayonnement est omnidirectionnel et que la polarisation est verticale, avec un bon niveau du gain. L'antenne monopole planaire insérée dans un MMD des dimensions limitées avec des pertes a été modélisée par un nouveau circuit équivalent multi résonant. Ce circuit est développé à partir de l'impédance d'entrée de l'antenne et des caractéristiques du MMD, et validé par les simulations avec un parfait accord entre les résultats
Airplanes with multiple navigation and communication systems require broadband VHF antennas. Reduce the size of these antennas is a major challenge while keeping good performances. This thesis proposes new configurations of low profile antennas using new nanocomposite non-conductive materials consisting of magnetic nanoparticles developed at Lab-STICC. A broadband planar monopole has been developed and optimized with a 60% miniaturization rate thanks to the use of a high permeability and low loss magneto-dielectric material covering only 5% of its surface. The experimental results, in almost perfect agreement with the simulations, show that the radiation pattern is omnidirectional and that the polarization is vertical, with a good level of gain. The planar monopole antenna inserted in a MMD of limited dimensions with losses was modeled by a new multi-resonant equivalent circuit. This circuit is developed from the input impedance of the antenna and the characteristics of the MMD. and validated by the simulations with a perfect agreement between the results

Abstract This dissertation presents wideband and multi-element antennas for mobile applications. It is divided into the following main parts: modal theory, wideband antennas, multi-element antennas, and wideband multi-element antennas. The radiating fields are first studied in terms of spherical scalar and vector modes, and it is shown how these modes correlate with the characteristic current modes on a planar mobile ground plane. The theory part shows how it is possible to excite the same modes on a conventional sphere and a rectangular planar mobile ground plane. The theory refers to the novel wideband antenna structures presented in this dissertation, in terms of current and radiating modes. After studying the modes, the dissertation shows how to excite a radiating antenna mode within a wide frequency bandwidth. To gain this, two main approaches are taken. First, a quasi-complementary antenna (QCA) structure with an electric conductor and magnetic slot is presented, and its characteristics are studied. A QCA UWB antenna, and a QCA element excited with a monopole or a dipole, is presented. The QCA structure compensates for the imaginary part of the input impedance on wide frequency bandwidth, when, at the same time, the fundamental mode is excited to ensure good radiating properties. The second approach uses a symmetrical feeding with two antenna elements to gain a wide frequency bandwidth, the relative -6 dB impedance bandwidth between 37.5–80%. When a field is symmetrically coupled to the conducting ground plane, the excitation avoids the awakening of higher order modes which might disturb the performance of the antenna. It is also shown, by using multiple feeding elements, that the excitation of orthogonal higher order modes on a small radiating ground plane is possible. As the modes are orthogonal to each other, they present a very low correlation. By using this kind of approach, radiation pattern diversity can be obtained in mobile applications within a small volume. On the other hand, when combining two QCA elements to a one multi-element antenna structure, a wideband diversity antenna with an 87.5% relative -6 dB impedance bandwidth, and a wideband MIMO antenna with a 95.0% relative -6 dB impedance bandwidth, are presented with excellent radiation and correlation properties. Also mutual coupling is need to be counted when multi-element antennas are designed. When designing an efficient radiator, it is important to consider an antenna feeding in terms of wideband impedance matching and wideband baluns, not to spoil the antenna performance. The efficient antenna structures and feeding mechanisms are obtained by using commercial 3D electromagnetic simulators to find the desired wideband antenna characteristics. Prototype antennas are measured in most of the presented structures to show their functionality in real. In general, the dissertation presents wideband antenna structures with radiating antenna modes excited on a planar conducting ground plane. The idea is to find structures and feeding mechanisms to excite the fundamental mode, or a certain radiating antenna mode, at a wide frequency bandwidth, by avoiding the excitation of higher order modes which might disturb the antenna performance. It is also shown that, by using multiple feeding elements, it is possible to excite higher order modes on a small antenna
Tiivistelmä Väitöskirjassa esitetään uusia laajakaistaisia ja monielementtiantenneja matkaviestimiin. Väitöskirja koostuu neljästä pääalueesta: pintavirtojen muototeoria, laajakaistaiset antennit, monielementtiantennit sekä laajakaistaiset monielementtiantennit. Teoriaosassa säteilykenttiä on aluksi tutkittu pallon pinnalla sekä skalaaripotentiaaleina että pintavirtavektoreina, jonka jälkeen niitä on verrattu mobiilin laitteen maatason ominaispintavirtojen synnyttämiin säteilykenttiin. Teoriaosassa osoitetaan, että pallon pinnalla sekä tasomaisella suorakaiteen muotoisella pinnalla on mahdollista herättää samat säteilykentät. Myöhemmin väitöskirjassa esitettävien uudenlaisten antennirakenteiden ominaisuuksia verrataan teoriaosassa esitettyihin pintavirtoihin ja säteilykenttiin. Teoriaosuuden jälkeen osoitetaan miten säteilevä sähkömagneettinen kenttä saadaan herätettyä laajalla taajuusalueella. Tähän on otettu kaksi eri lähestymistapaa, joista ensimmäisessä esitellään ja tutkitaan kvasikomplementaarista antennirakennetta (QCA). Kvasikomplementaarisessa antennirakenteessa sisääntuloimpedanssin imaginaariosa kompensoidaan yhdistämällä sähköinen johde ja magneettinen rako samaan antenniin. Samanaikaisesti perusmuoto herätetään laajalla taajuusalueella, jolla varmistetaan antennin hyvät säteilyominaisuudet koko toimintataajuusalueella. Toisessa lähestymistavassa käytetään kahta symmetrisesti asetettua antennielementtiä, joita syötetään symmetrisesti samalla amplitudilla ja vaiheella. Kun sähkömagneettinen kenttä herätetään symmetrisesti, korkeamman kertaluvun muotojen herättäminen voidaan välttää laajalla taajuusalueella. Symmetrisesti syötetyillä antennirakenteilla saavutettu -6 dB suhteellinen impedanssikaistanleveys on 37.5–80 %. Useita syöttöelementtejä käytettäessä voidaan mobiilin laitteen maatasossa herättää yhdellä pistetaajuudella monta toisistaan riippumatonta säteilykenttää. Koska herätetyt kentät ovat toisistaan riippumattomia, on niiden välinen korrelaatio myös pieni. Kyseisellä rakenteella on mahdollista toteuttaa säteilykuviodiversiteetti erittäin pienessä tilassa, kuten matkapuhelimessa. Toisaalta, kun yhdistetään kaksi QCA-elementtiä yhdeksi monielementtiratkaisuksi, voidaan toteuttaa laajakaistainen diversiteettiantenni, jonka suhteellinen -6 dB impedanssikaistanleveys on 87.5 %. Vastaavasti kahdella laajakaistaisella QCA-elementillä toteutetulla MIMO-ratkaisulla päästään 95 % suhteelliseen -6 dB impedanssikaistanleveyteen. Molemmilla ratkaisuilla on erittäin hyvät säteilyominaisuudet sekä alhainen korrelaatio ja pieni keskinäiskytkentä antennielementtien välillä. Suunniteltaessa toimivaa laajakaistaista antennirakennetta, on tärkeää ottaa huomioon antennisyötön impedanssisovitus, jotta antennin suorituskyky ei heikkenisi. Lisäksi balansoidussa rakenteissa tulee olla laajakaistainen baluni, jolla vältetään säteilykuvion vääristyminen. Väitöskirjan syöttöratkaisuissa on käytetty kaupallisia sähkömagneettisia simulaattoreita, joilla antennirakenne voidaan mallintaa kolmiulotteisesti, ja joilla laajakaistainen syöttö saadaan optimoitua haluttuun antenniin. Suurin osa esitellyistä antennirakenteista on simulointien lisäksi myös mitattu, jolloin niiden toimivuus käytännössä pystytään todentamaan rakentamalla prototyyppiantenni. Yleisesti väitöskirjassa esitellään tasomaisia antenniratkaisuja johtavassa maatasossa, joissa säteilevät pintavirrat herätetään mahdollisimman laajalla taajuusalueella. Ideana on löytää laajakaistaisia antenni- ja syöttörakenteita, joilla saadaan herätettyä perusmuoto tai jokin muu haluttu muoto. Ajatuksena on välttää korkeamman kertaluvun muotojen herättäminen, jotka voivat pilata antennin suorituskyvyn. Väitöskirjassa osoitetaan myös, että pienikokoisella antennilla on mahdollista herättää korkeamman kertaluvun muotoja pistetaajuudella käyttämällä useita heräte-elementtejä

De nos jours, les communications sans fil sont devenues un moyen incontournable et universel d'échange d'un large éventail d'informations entre différents systèmes, certains d'entre eux étant en mouvement comme des drones parmi tant d'autres. Dans le contexte de cette thèse nous considérons une liaison entre un projectile et une station de base. La géométrie de la structure ainsi que les contraintes aérodynamiques d'un tir balistique impliquent l'utilisation d'antennes patchs dans la partie conique à l'avant du projectile. Ce type d'antenne est facile à intégrer à une plate-forme en tant que réseau conformé tout en respectant les contraintes d'encombrement. Ces communications doivent être fiables et discrètes dans un environnement perturbé ou hostile. Les diagrammes de rayonnement du réseau d'antennes doivent présenter des caractéristiques spécifiques, notamment dans le cas particulier d'objets volants et possédant une rotation en roulis (rotation autour de son axe) qui impliquent l'utilisation d'un réseau phasé et commuté par rapport à sa position. Une antenne qui présenterait un rayonnement fixe assurerait une liaison avec un interlocuteur, mais rayonnerait également dans d'autres directions sensibles ce qui pourraient interférer avec la communication principale. La solution qui consiste à activer et désactiver des sous-réseaux verticaux afin d'orienter le lobe principal dans la plan orthogonal à la pointe semble être en accord avec les contraintes de la structure tournante. Un réseau conique a été étudié puis 2 prototypes ont été fabriqués, dont un à l'ISL. Les sous-réseaux sont répartis de manière égale autour de la pointe de façon à pouvoir rayonner dans toutes les directions. De plus, chaque sous-réseau est composé de trois éléments ce qui permet d'orienter également le lobe principal dans le plan longitudinal de la pointe (le long de l'axe du projectile) grâce à un dépointage électronique. Un système électronique de formation de faisceaux a été développé dans le but de contrôler 12 éléments rayonnants. Le réseau d'antennes ainsi que le circuit de répartition ont été caractérisés dans un premier temps de manière indépendante afin d'optimiser les lois de phase nécessaires à dépointer le lobe à partir des pondérations mesurées. Au final, le réseau de 12 éléments associé à son système d'alimentation dédié a été mesuré dans les chambres anéchoïques de DGA-MI et de l'ISL et les mesures sont en accord avec les simulations
Nowadays wireless communications have become a useful and universal mean to exchange a wide range of information between different systems, some of them being moving, as UAVs among others. In this context we consider here the link between a projectile and a base station. The shape of the structure and the aerodynamic constraints involve the use of patch antennas in the conical front part. This class of antenna is easy to be integrated into the platform as a conformal array, while respecting space constraint. Communications have to be reliable and discrete in disturbed or hostile environment. Antennas array radiation patterns must have some specific characteristics, in particular in the case of flying objects with spin which involves the use of a switched phased array considering its roll position. A fixed-radiation pattern antenna may presents a relevant level or gain toward the interlocutor, but also toward sensitive directions, in which may be located others systems, interfering with the current communication. The solution to switch on and off vertical sub-arrays to steer the beam in the azimuthal plane seem convenient ant fitting the requirements of rotating platform. A conical phased array was studied and two prototypes were manufactured, one at ISL. Sub-arrays are distributed around the conical shape in order to be able to radiate in each direction. Moreover, each sub-array are composed of three radiating elements allowing to steer the main antenna beam in many direction (along the projectile fuze axes). A beam forming network was developed to control the 12 radiating elements conical array. The antenna array and the feeding network were characterized independently in order to optimized the phase of each radiating element. Finally, measurements were done on the whole system in the DGA-MI and ISL anechoic chambers and are in good agreement with simulation results

FUNDAÇÃO DE APOIO À ESCOLA TÉCNICA
Com a implantação e disseminação de novos sistemas celulares,principalmente a partir dos anos 80, novas tecnologias foram desenvolvidas, o número de celulares cresceu de forma surpreendente, como conseqüência, o aumento de Estações Radio Base. É fato, também, que as pessoas, de modo geral, estão expostas às radiações emitidas pelas ERBs através de suas antenas. Como a população, a mais interessada na busca de respostas adequadas e convincentes, não tem qualquer controle sobre tais níveis, cabe as autoridades a preocupação maior em garantir que os níveis de exposição não sejam excedidos. A partir deste quadro preocupante a OMS estabeleceu em 1996 o International EMF Project para avaliar as evidências cientificas existentes sobre possíveis efeitos de campos eletromagnéticos à saúde,incluindo nestes os efeitos emitidos pelos próprios aparelhos celulares e por suas estações rádio-base. Este trabalho pretende contribuir no equacionamento desta questão, tão polemica e controversa. Iniciando com a evolução do número de celulares no Brasil, mostrando as funções básicas dos componentes de uma estrutura celular. No momento seguinte são mostrados alguns efeitos biológicos relacionados à radiação não-ionizante pesquisados na literatura. Tais efeitos, polêmicos e controversos, são amplamente discutidos por especialistas de diferentes linhas de pesquisa. O trabalho mostra, também, os resultados de uma campanha de medidas com as densidades de potência obtidas através de duas metodologias. Inclui, também, conceitos e características de percepção de risco e alguns resultados da pesquisa qualitativa de campo. Ao final são apresentadas as conclusões e sugestões para trabalhos futuros relacionados ao tema.
With the implantation and spread of new cellular systems, mainly starting from the eighties, new technologies were developed, the number of cellular grew in a surprising way, as consequence, the Base Stations increased, too. The people, in general, are exposed to the radiations emitted by ERBs antennae. As the population doesn't have any control on such levels, people are always looking for appropriate and convincing answers. So, the authorities are concerned in guaranteeing that the exposition levels are not exceeded. Based on preoccupying issue, the World Health Organization (WHO) established in 1996 International EMF Project to verify the scientific evidence of possible health effects of Electromagnetic Field. This work intends to contribute in the set out of this controversial subject. At first, the cellular number evolution in Brazil is presented. In addition, the basic cellular structure components functions are described. The following topic presents some biological effects related to the non-ionizing radiation are presented according to the literature. Such controversial effects are discussed thoroughly by specialists of different research lines. This work also shows the power densities results obtained through two methodologies. Afterwards, concepts, risk perception characteristics and some results from a qualitative research are presented. At the end, the conclusions and suggestions for future works related to the same theme are shown.

L'objectif de cette thèse est d'exploiter les phénomènes des ondes de fuite pour améliorer les performances des antennes classiques à ouverture pour les applications spatiales. Ici, nous considérons des configurations planaires où les ondes de fuite sont excitées entre un plan de masse et un superstrat partiellement réfléchissant. Des réseaux de petites ouvertures sur le plan de masse sont utilisés pour alimenter les antennes considérées. Les structures avec superstrat sont développées en configuration réseaux simples ou réseaux à commande de phase, considérées intéressantes en termes de flexibilité du système pour des liens satellitaires de nouvelle génération.Pour étudier efficacement ces antennes, nous avons développé un outil d'analyse basé sur une approche spectrale avec fonction de Green. Cet outil permet d'analyser les structures proposées en prenant en compte l'impact du couplage mutuel entre les éléments sur les performances de rayonnement avec une réduction du temps de calcul et d'utilisation de mémoire.L'augmentation du gain des structures à ondes de fuite peut ouvrir la voie à la réduction du nombre d'éléments des réseaux associés, et donc des commandes en amplitude et phase. Dans une configuration à ondes de fuite, chaque élément du réseau rayonne avec une ouverture équivalente plus grande, augmentant ainsi l'espacement entre les éléments sans affecter le gain global de la structure. Comme largement expliqué dans le manuscrit, les solutions à ondes de fuite représentent par conséquent un avantage majeur pour les antennes du segment utilisateur.En plus de l'amélioration du gain, la technologie à ondes de fuite peut être efficacement exploitée pour synthétiser le diagramme de rayonnement, en choisissant correctement les paramètres de conception de l'antenne. Cette caractéristique peut être utilisée dans les réseaux à commande de phase, pour produire un diagramme d'élément qui minimise les pertes par dépointage et qui filtre les lobes de réseaux. Une procédure de synthèse pour des antennes réseaux raréfiés à ondes de fuite est ainsi présentée dans le manuscrit, ainsi qu'une nouvelle configuration de réseaux avec superstrat irrégulier. Ce dernier permet de réduire les lobes secondaires de l'antenne en utilisant une excitation uniforme. Cette dernière configuration montre clairement que la capacité de modifier le diagramme de rayonnement est la caractéristique la plus attrayante des antennes planaires à ondes de fuite, pour être utilisée dans des solutions de réseaux à commande de phase
The objective of this thesis is to exploit the leaky-wave phenomena to enhance the performance of classical aperture antennas for space applications. Here, we consider planar configurations where the leaky modes are excited between a ground plane and a partially reflective superstrate. Arrangements of small apertures opening on the ground plane are used to feed the antennas under study. The superstrate-like leaky-wave structures are developed in array or phased array configurations, considered of interest in terms of flexibility of the system for next generation satellite links. In order to efficiently study planar leaky-wave arrays, we have developed an analysis tool based on a Green's function spectral approach. The developed tool allows to precisely analyze the proposed structure by taking into account the impact of the mutual coupling among the elements on the radiation performance of the whole antenna. In addition, it can handle extremely large structures in terms of wavelengths with a small computational effort with respect to commercial tools. In particular, the gain enhancement of leaky-based structures can pave the way to the reduction of the number of elements of the associated phased arrays. In a leaky-wave configuration each element of the array will radiate with a larger equivalent aperture allowing a larger spacing among elements without affecting the final gain of the whole structure. This aspect is particularly important in the case of phased arrays, where phase shifters and control cells are, typically, the most expensive components of the system. As extensively explained in the manuscript, antennas for user segment might find the highest benefit by using leaky-wave solutions. Besides the gain enhancement, the leaky-wave technology can be effectively exploited to conveniently shape the radiation pattern by properly engineering the design parameters of the antenna. This capability can be used in phased arrays to generate a convenient element pattern to minimize the scan losses and filter the grating lobes appearing in the visible space when dealing with periodicities larger than a wavelength. Therefore, a synthesis procedure for thinned leaky-wave arrays is presented in the manuscript. Also, a novel array configuration, the irregular superstrate array, is presented. The irregular superstrate allows the reduction of the side lobes of the antenna below -20 dB in the considered 2.5 % band, using a uniform excitation. This last configuration clearly shows that the shaping capability of leaky-wave antennas is the most appealing feature to be used in phased array solutions

The Antennae (22 Mpc) is one of the most well-known mergers in the nearby Universe. Its distance allow us to observe and study the gas at the scales of stellar cluster formation. It is an ideal source to understand how the galaxy dynamics in mergers trigger the formation of stars. Most of the stars in the Antennae are formed in compact and massive stellar clusters, dubbed super-star clusters (SSCs). The most massive (>106 M⊙) and youngest (<6 Myr) SSCs are located in the overlap region, where the two galaxies collide, and are associated with massive (several 108 M⊙) and super-giant (few hundred of pc) molecular complexes (SGMCs). The formation of SSCs must involve a complex interplay of merger-driven gas dynamics, turbulence fed by the galaxy interaction, and dissipation of the kinetic energy of the gas. Within SGMCs, a hierarchy of structures must be produced, including dense and compact concentrations of molecular gas massive enough to form SSCs, pre-cluster clouds (PCCs). For star formation to occur, the mechanical energy of PCCs must be radiated away to allow their self-gravity to locally win over their turbulent gas pressure. Specific tracers of turbulent dissipation are therefore key inputs to test the validity of this theoretical scenario. In my thesis, I studied the Antennae overlap region. My work is based on observations with the SINFONI spectro-imager at the VLT, which includes H2 rovibrational and Brγ line emission, and with ALMA, which includes the CO(3-2) line and dust continuum emission. Both data-sets have the needed sub-arcsecond angular resolution to resolve the scales of SSC formation. The spectral resolutions are enough to resolve motions within SGMCs. Combining CO and H2 line emission is key in my PhD work. I use CO as a tracer of the distribution and kinematics of the molecular gas, and H2 as a tracer of the rate at which the gas mechanical energy is dissipated.My thesis focuses on diverse sources in the Antennae overlap region which trace different stages of star formation: the gathering of mass necessary to form SGMCs, the formation of PCCs within SGMCs and the disruption of a parent cloud by a newly formed SSC. I show that at each stage turbulence plays a key role. I found that the kinetic energy of the galaxies is not thermalized in large scale shocks, it drives the turbulence in the molecular ISM at a much higher level than what is observed in the Milky Way. Near-IR spectral diagnostics show that, outside of SSCs embedded in their parent clouds, the H2 line emission is powered by shocks and traces the dissipation of the gas turbulent kinetic energy. I relate the H2 emission to the loss of kinetic energy required to form gravitationally bound clouds. This interpretation is supported by the discovery of a compact, bright H2 source not associated with any known SSC. It has the largest H2/CO emission ratio and is located where the data show the largest velocity gradient in the interaction region. To our knowledge, this is the first time that an extragalactic source with such characteristics is identified. We would be witnessing the formation of a cloud massive enough to form a SSC. The data also allow us to study the disruption of a parent molecular cloud by an embedded SSC. Its matter is loosely bound and its gravity would be supported by turbulence, which makes it easier for feedback to disrupt the parent cloud. I end my manuscript presenting two projects. I propose to establish additional energy dissipation tracers observable with ALMA, which gives us the high spatial and spectral resolution needed to isolate scales at which clusters form. This is a Cycle 1 proposal accepted in first priority. I also plan to expand my work to other nearby extragalactic sources by investigating the turbulence-driven formation of stars in different extragalactic sources by combining near-IR and submillimeter observations.

O presente trabalho trata do estudo, projeto, desenvolvimento, construção e medida de lentes discretas planares (DLAs). Estes dispositivos atuam como sistemas irradiantes, especialmente com características multi-feixes. A construção destas lentes utiliza tecnologias compatíveis com a fabricação de circuitos impressos, com alguns detalhes que são característicos da área de antenas e circuitos planares. O estudo aborda as equações de projeto e considerações gerais relativas ao atendimento de especificações técnicas preliminares. Foram desenvolvidas duas lentes discretas, uma na frequência de 8GHz (banda X) e outra na frequência de 40GHz (banda Ka- faixa de ondas milimétricas). São apresentados os resultados de medidas destas duas lentes, que comprovam a possibilidade de uso em aplicações multi-feixes, bem como seu efeito de foco, análogo ao observado em lentes óticas comuns.
The object of this work is the study, design, development, fabrication and measurement of discrete lens arrays (DLAs). These devices act as radiant systems, especially with multi-beam characteristics. Their construction follows the same procedures and techniques normally found in printed circuit fabrication, with some further details that are pertinent to the antenna and planar circuit field. This study contains the design equations and general remarks as to fulfill preliminary technical specifications. Two real designs were developed, one in the X-band (8GHz) and another in the millimeter range, Ka band (40GHz). Their respective measurement results are presented, which proved their possible application in multi-beam systems, as well as their focusing effect, which is analogous to that observed in common optical lenses.

L’Internet-of-Things désigne un développement en plein essor d’objets interconnectés et qui sont susceptibles de modifier nombre de services au sein de l’industrie comme pour la personne. Les développements actuels buttent sur plusieurs verrous dont celui de l’autonomie énergétique des objets ou encore des procédés de fabrication économiquement acceptables et respectueux de la planète. Dans ce contexte, la récupération d'énergie est une thématique largement répandue faisant appel à des sources très variées (mécanique, thermique, électromagnétique...). Cette thèse est notamment orientée vers la récupération d'énergie électromagnétique ambiante. Le second point caractéristique de cette thèse est de s'intéresser à des substrats souples et si possible recyclables. Le défi consiste à récupérer l’énergie provenant d’un champ électromagnétique ambiant extrêmement faible : ceci concerne l’antenne, qui doit par ailleurs répondre à une exigence de flexibilité pour son intégration future à un objet souple et déformable, et l’électronique de traitement de l’énergie.Le travail de thèse est articulé autour de trois phases principales :Dans la première phase, il s’agissait de l’étude des structures d’antennes compatibles en fréquence et en puissance reçue avec l’application de récupération d’énergie et une réalisation physique sur base souple (papier, tissu...). Cette phase a permis de présenter les différentes approches pour combiner les sources RF.Dans la deuxième phase, il s’agit de l’étude sur le rôle de circuits redresseurs dans le système de récupérer d’énergie. Les méthodes d'extraction des paramètres sont discutées en dissociant chaque élément et leurs rôles. De nombreuses mesures ont été réalisées afin de comparer différents modèles de la diode utilisée pour le redressement, en tenant compte également de l'impact réel du processus de fabrication et du processus de mesure.Une troisième phase permet l’optimisation de l’ensemble antenne et électronique (rectenna) pour divers scenarii et le suivi de la variabilité pour maintenir les pertes du système a minima. La réalisation de démonstrateurs pertinents, testés et caractérisés est présentée
Internet-of-Things means a growing development of interconnected objects that are likely to change many services within the industry as well as for the individual. Several barriers, including the energy autonomy of objects or production processes that are economically acceptable and respectful of the planet, hamper current developments. In this context, energy recovery is a widespread theme using a wide range of sources (mechanical, thermal, electromagnetic, etc.). This thesis is oriented towards the recovery of ambient electromagnetic energy. The second characteristic point of this thesis is to focus on flexible and, if possible, recyclable substrates. The challenge is to recover energy from an extremely low ambient electromagnetic field: this concerns the antenna, which must also meet a requirement for flexibility for its future integration with a flexible and deformable object, and the electronics of energy processing.The work of this thesis conducted in three phases.In the first phase, it was the study of the antenna structures compatible with frequency and power received with the energy harvesting application and a physical realization on flexible base (paper, textile, etc.). This phase allowed presenting the different approaches to combining the RF sources.In the second phase, the study on the role of rectifying circuit in the system of recovering wireless energy was presented. Methods for extracting parameters were discussed by separating each element and its roles. Numerous measurements have been conducted to compare different models of the diode, taking into account also the actual impact of the manufacturing process and the measurement process.A third phase allows the optimization of the antenna and electronic assembly (rectenna) for various scenarios and the monitoring of variability to keep the losses of the system at minima. The production of relevant demonstrators, test and characterization were presented

In this dissertation, the operation of dual-linear polarized antennas is considered in order to provide ideal performance suited for several applications including polarimetric synthetic aperture radar (SAR), wireless and satellite communications. The underlying objectives realized in this work are reported as design realizations of dual-linear polarized antennas with low cross polarization patterns and high isolation between ports that employ special properties of the electromagnetic metamaterial (MTM) structures. Some of these key properties appear as negative permittivity, negative permeability, negative refractive index, and antiparallel nature of the phase velocity and the group velocity. The antenna design is carried out at two frequencies, 5.5 GHz and 10 GHz, and key physical issues that affect the operation of dual-linear polarization operation antennas are treated in light of electromagnetic MTM properties. It’s well known that a dual linear polarized antenna poses a big challenges such as cross polarization patterns and high mutual coupling between two input ports. Therefore, these drawbacks are key topic that receive significant attention in literature which reports on how to mitigate these drawbacks, however, at the expense of complexity of the antenna structures. The MTM structures have received considerable coverage in antenna research for obtaining size reduction, directivity enhancement, and beam steering. For this purpose, different MTMs structures are chosen in this thesis for achieving additional improvements, while keeping the antenna design as simple as possible, something which is very difficult to accomplish using conventional design methods
In der folgenden Dissertation wird der Einsatz von zweifach linear polarisierten Antennen zur idealen Ausführung von verschiedenen Anwendungen, einschließlich von polarimetrischen Synthetic Aperture Radar (SAR), kabellose und satellitengestützte Kommunikation, diskutiert. Die Ziele dieser Arbeit werden dargestellt durch die Gestaltung von zweifach linear polarisierten Antennen mit gering Kreuz-Polarisationsmustern und die starke Isolation zwischen den Ports durch die einzigartigen Eigenschaften der Strukturen des elektromagnetischen Metamaterials (electromagnetic metamaterial; MTM). Einige dieser Eigenschaften treten als negative Permittivität, negative Permeabilität, negativer Brechungsindex und als antiparallel Richtungen (Gegenvektor) der Phasen-und Gruppengeschwindigkeit auf. Somit wird die Antennengestaltung auf zwei Frequenzen übertragen, 5,5GHz und 10 GHz, und die Ausführung der zweifach linearen Polarisation wird durch die elektromagnetischen Eigenschaften des MTM illustriert. Weil die Kreuzpolarisationsmuster und starke gegenseitige Koppelung zwischen zwei Input-Ports bei einer zweifach linear polarisierten Antenne große Schwierigkeiten bereiten, werden diese im Großteil der Fachliteratur als Schwerpunkte gesetzt, was zu einer Milderung der Nachteile führte, jedoch dafür die Komplexität der Antennenstruktur zunahm. Die Vielfalt an MTM ist ein bedeutender Teil im Bereich der Antennenforschung einschließlich der Größenverkleinerung, der Verbesserung der Richtcharakteristik und der Strahlensteuerung. Für diesen Zweck werden in dieser Dissertation verschiedenste MTM Strukturen ausgewählt um weitere Verbesserungen der Antennenstruktur zu ermöglichen und gleichzeitig die Einfachheit der Struktur zu bewahren, was mit konventionellen Gestaltungsmethoden nur schwer zu erreichen ist

Cette thèse a pour objectif l’étude et la recherche d’amélioration de la technologie d’antenne réseau superdirective. Cette technologie a récemment été rééxaminée dans la littérature car elle peut apporter des fonctionnalités intéressantes pour les applications de télécommunication futures. L’examen de ce type d’antenne est donc conduit à travers l’outil de la décomposition en ondes sphériques qui permet l’étude générale des limites de directivité ou de gain, en considérant des pertes d’énergie dans l’antenne. La théorie classique des antennes réseau end-fire est aussi revue, dans le cas de réseaux à espace inter-éléments uniformes et à éléments indépendamments excités. Cette étude fournit une évaluation analytique de l’efficacité et de la sensibilité à la précision des coefficients d’excitation.Les dipôles infinitésimaux et les sources de Huygens sont considérés dans une proposition de développement qui lie la théorie des réseau et de la décomposition en ondes sphériques. Cette contribution fournit une preuve formelle de la limite de directivité des réseaux end-fire de sources de Huygens ainsi qu’une borne supérieure de la directivité des réseaux de dipôles, quand la distance inter-éléments tend vers zéro.. De plus, il est montré comment la théorie classique des antennes réseau peut aussi être utilisée pour extraire des coefficients d’excitations qui maximisent le gain plutôt que la directivité, quand des résistances de pertes sont considérées. Un examen est aussi fait selon la taille d’antenne pour montrer quelles conditions sont les plus favorables pour l’utilisation de réseaux end-fire optimisés pour le supergain ou pour la superdirectivité.Dans une seconde partie, les implémentations pratiques d’antennes superdirectives sont revue dans l’état de l’art, en se concentrant sur les sources de Huygens et les réseaux compacts end-fire. L’architecture d’implémentation choisie de réseau à éléments parasites est ensuite détaillée est étudiée dans le but de minimiser le recours à des résistances positives ou négatives. Cela mène à la conception et aux mesures de cinq prototypes qui visent à atteindre le maximum de gain ou de directivité possible, pour une taille d’antenne limitée, avec des réseaux end-fire de deux, trois et quatre dipôles
The purpose of this thesis is to study and seek improvement of the superdirective antenna array technology. This technology has been recently re-examined in the literature since it can bring some interesting functionalities in the future telecommunication applications. The examination of this type of antenna is thus conducted through the use of Spherical Wave Expansion which allows for the general study of directivity limits as well as gain limits, considering lossy antennas. The classical theory of end-fire array antennas is also reviewed, in the case of uniformly spaced tapered arrays, providing theoretical evaluation of efficiency and sensitivity to source feeding precision.Infinitesimal dipoles and Huygens sources are considered in a proposed development that links array theory and Spherical Wave Expansion. This contribution provides a formal proof for the directivity limit of Huygens-source-based end-fire arrays as well as an upper bound for the directivity of dipole-based arrays, when the inter-element spacing tends to zero. Moreover, it is shown how classical array theory can also be used to derive excitation coefficients that maximize gain rather than directivity, when loss resistances are considered. An examination over antenna size is also made to demonstrate which conditions are most favorable for the use of such supergain or superdirective end-fire array optimization.In a second part, practical implementations of superdirective antennas are surveyed, focusing on Huygens sources and compact end-fire array designs. The chosen implementation architecture of parasitic element arrays is then detailed and studied, in order to minimize the requirement for negative or positive resistive loads. This lead to the design and measurement of five prototypes that aim at achieving the maximum possible gain or directivity for a limited radiator size, with two-, three- and four-dipole end-fire arrays

The pharmacological disruption of memory by various protein synthesis inhibitory drugs (PSIs) has implicated protein synthesis as a requirement for long term learning but not for short. However, evidence derived from PSI research remains equivocal, with the apparent amnesic effects of PSIs being attributed to drug side-effects and general behavioural debilitations. Research reported in this thesis investigates the behavioural effects on short and long term habituation of the dorsal antennae withdrawal reflex in the snail (Helix aspersa) of three antibiotic drugs known to reversibly inhibit protein synthesis; anisomycin, actinomycin D, and puromycin. Initially, habituation was established as true learning in the snail and was demonstrated to be capable of retention for over 24 hours from one training session and over 6 months from a series of training sessions. The parametric characteristics of both short and long term habituation in the snail was established and found to be identical to those demonstrated in vertebrate habituation. Such characteristics were found to be different for short and long term habituation. Injection of PSIs showed no effect on short term habituation but disrupted long term habituation if PSI was active within a 'critical time window' during or for approximately 40 minutes after training. Later injections had no amnesic effect, and neither did injections 2 hours prior to training. The amnesic effects were demonstrated not to be attributable to drug side-effects by the development and application of a 'behavioural test battery' to screen general snail behaviour for drug induced debilitations at a variety of doses. Dose/amnesic effect relationships are also reported. Potentially confounding effects, such as, state dependent learning, and drug performance effects, were controlled out. The effects of the PSIs on short and long term habituation are then reported in terms of their effects on the established short and long term parametric characteristics of the learning. Drug injected snails showed normal short term parametric characteristics in training. However, in a long term retest drug treated snails also showed the parametric characteristics of short term habituation which demonstrated the degree of induced amnesia. The results are discussed in terms of a gene expression model of long term habituation and suggest that short and long term habituation are mediated by different processes. Short term habituation is protein synthesis independent and long term habituation is protein synthesis dependent.

Les interactions entre individus sont un socle vital pour l’organisation des colonies d’abeilles, en particulier lors du recrutement pour le butinage. Outre la communication de la localisation d’une source de nourriture par la fameuse danse, les abeilles recrutées apprennent les caractéristiques de l’odeur des fleurs butinées au cours de transferts de nectar (trophallaxie). Les mécanismes de cet apprentissage ne sont pas encore éclaircis car il est parfois effectif sans aucun transfert de nectar, suggérant que d’autres mécanismes, comme par exemple d’apprentissage social, sont impliqués. Nous avons reproduit cette interaction en laboratoire, suivant un protocole basé sur le conditionnement olfactif appétitif de la réponse d’extension du proboscis (REP). Ici, un composé odorant initialement neutre (Stimulus conditionnel) était associé à un contact avec une congénère (Stimulus Inconditionnel social), sans récompense sucrée. Nos expériences montrent que ce simple contact social entre congénères peut constituer un renforcement pour les abeilles. A la suite de cette association, celles-ci montrent donc des REP à l’odeur préalablement associée au contact social. Nos expériences montrent de plus que des contacts antennaires entre les abeilles sont indispensables à l’efficacité de cet apprentissage social, représentant un indice social tactile. Nous avons alors développé un dispositif permettant d’enregistrer les mouvements des antennes de manière précise et à haute vitesse (90 hz) et étudié les différents facteurs modulant les mouvements antennaires des abeilles. Les abeilles montrent des réponses contrastées et reproductibles à des odeurs de valeurs biologiques différentes. De plus, le couplage de ces enregistrements à des expériences de conditionnement associatif montre que ces réponses antennaires sont plastiques et modifiées par l’expérience des individus. Ce travail a permis de mettre en lumière un nouveau type d’apprentissage social chez les insectes et d’approfondir l’étude des mouvements antennaires comme indicateurs de l’état motivationnel, attentionnel et physiologique des abeilles ainsi que de la valence des stimuli perçus
In honeybees, interactions between individuals are cornerstones for the organization of the colony, especially during recruitment for foraging. Besides learning the location of a food source thanks to the well-known dance, the recruited bees learn the characteristics of odors of foraged flowers through nectar transfer (trophallaxis). The underlying mechanisms are still unclear because this learning can occur without any nectar transfer, suggesting that other, probably social, learning mechanisms are involved. We reproduced this interaction in the lab, using a protocol based on the appetitive olfactory conditioning of the proboscis extension response (PER). Here, an initially neutral odorant (conditioned stimulus) was associated with a contact with a nestmate (social unconditioned stimulus), without any sugar reward. Our experiments show that this simple social contact between workers can act as a reinforcement for bees. As a result, they show PER to the odor previously associated with a social contact. We further demonstrate that antenna contacts are essential for the effectiveness of this social learning, representing a tactile social cue. We thus developed a system allowing to record bees’ antennal movements accurately and at high frequency (90 hz). We then determined the factors modulating bees’ antennal movements. First, we show that bees display contrasted and reproducible responses to odors of different biological values. Second, the coupling of these recordings with associative conditioning experiments shows that these antennal responses are plastic and modified by individual experience. This work has shed light on a new type of social learning in insects and has furthered our understanding of antennal movements as indicators of the motivational, attentional and physiological state of bees and of the valence of perceived stimuli

L'évolution des technologies numériques a permis l'introduction d'objets connectés dans le quotidien d'une grande partie de la population mondiale. Face à une demande de données sans-fil toujours croissante, des techniques nouvelles doivent être employées pour offrir un débit plus élevé à des appareils moins volumineux et accessibles à un prix raisonnable. Les antennes constituent l'organe central de toutes les télécommunications et elles jouent un rôle majeur dans l'évolution vers des systèmes plus performants. En effet, l'augmentation du débit de données passe par une augmentation du gain et de la bande de fonctionnement, et plus une antenne est directive plus son intégration est complexe. La tendance actuelle est à l'évolution vers les bandes de fréquences millimétriques, ce qui permet une réduction du volume de l'antenne et l'utilisation de bandes de fréquences plus larges, néanmoins la fabrication est un vrai défi technologique. Les travaux de recherches effectués au cours de cette thèse portent sur la conception d'antennes pour une application de lien backhaul : une liaison en bande E (71-86GHz) entre deux antennes fixes utilisée dans un réseau cellulaire ; cependant les concepts et technologies sont facilement transposables à d'autres applications telles que les radars ou les communications satellitaires. Les systèmes étudiés combinent un réseau unidimensionnel de longues fentes rayonnantes (CTS) alimentées en parallèles avec un formateur de faisceau quasi-optique (système pillbox). Les fentes rayonnantes consistent en guides à plans parallèles (GPP) tronqués. Elles sont alimentées en parallèle par un réseau de division de puissance exclusivement basé sur des GPP. Le système pillbox est constitué de deux GPP connectés par un coupleur et un réflecteur parabolique intégré, l'illumination de ce dernier par une source focale génère une onde plane. L'omniprésence de GPP au sein de l'antenne garantit une large bande de fonctionnement, et l'architecture employée permet une meilleure intégration que les antennes quasi-optiques. Ces antennes offrent donc un compromis entre un gain élevé, une large bande de fonctionnement et un profile réduit qui ne peut pas être atteint avec les autres structures présentes dans la littérature. Malheureusement ces antennes comportent également des désavantages. D'un point de vue technologique, leur fabrication est complexe et coûteuse. C'est pourquoi dans ces travaux de thèse un intérêt particulier est porté sur l'utilisation de techniques nouvelles permettant la fabrication de prototypes menant à des résultats expérimentaux. Du point de vue des performances en rayonnement, les antennes CTS/pillbox actuelles ne permettent pas de reconfigurer le rayonnement dans le plan E et le niveau de recouvrement dans le plan H est trop faible pour pouvoir être facilement exploité. Dans cette thèse, des solutions innovantes sont proposées afin de remédier à ce manque de versatilité. Enfin jusqu'à présent, le niveau des lobes secondaires dans le plan E de l'ensemble des antennes CTS alimentées en parallèle est d'environ -13,5dB. Une structure nouvelle est introduite afin de permettre une réduction de ces lobes secondaires à un niveau très faible
The evolution of numerical technologies allowed the daily use of connected object for a large part of the world’s population. To fulfill the ever-growing demand for wireless communication, new technologies have to be developed in order to obtain higher data-rate with smaller and cheaper devices. The antenna plays a major role in communication systems and their performances are to be improved to obtain more efficient telecommunications. Indeed the rise of data-rate involves an improvement of the antenna gain and bandwidth, but the integration of directive antennas is always challenging. The actual trend is the shift to higher frequency bands, in the millimeter-wave range, this allows a size reduction together with the use of broader bandwidth; however the fabrication becomes a real challenge. The research work realized in this thesis concern the design, fabrication and experimental characterization of antennas for backhaul links: the E-band (71-86GHz) communication between two fixed antennas used in cellular network; nonetheless the solutions developed can easily be applied to other applications such as radar or satellite communications.The studied systems combine a one-dimensional array of long radiating slots (CTS) fed in parallel with a quasi-optical beam forming network (pillbox system). The radiating slots are made of truncated parallel plate waveguides (PPW) and are fed in parallel by a power-divider network realized in PPW technology. The pillbox system consists of two stacked PPWs connected by a multi-slot coupler and an integrated parabolic reflector, the latter converts the cylindrical wave emitted by a focal feed into a planar wave. The omnipresence of PPWs throughout the antenna system insures a broad band of operation, and the architecture shows a lower profile than quasi-optical antennas. This antenna presents an unequaled tradeoff between a high gain, a wide bandwidth and a low-profile. Unfortunately they also have drawbacks. From a technological point of view, their fabrication is complicated and expensive. This is why in this thesis a particular attention is given to the use of new techniques allowing the fabrication of prototypes leading to experimental validation of the results. From the radiation performance point of view, CTS/pillbox antennas do not show any reconfigurability solution in the E-plane and the overlap level obtained in H-plane with already existing antennas is too low to be usable. In this thesis, innovative solutions are investigated to find solution to this lake of versatility. Finally the sidelobe level (SLL) in E-plane of the totality of parallel-fed CTS antennas described in the open-literature is about -13.5dB. A new architecture introduced in this thesis allows a reduction of this SLL down to a negligible level

International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California
Modern spectrally efficient telemetry transmitters are beginning to find their way on a variety of airborne test platforms. Many of these platforms also include Global Positioning System (GPS)-based Time-Space-Position-Information (TSPI) instrumentation systems. Due to space and other limitations, many of these platforms have demanding antenna placement limitations requiring closely spaced antennas. This paper describes steps taken to identify and mitigate potential interference to GPS-based TSPI instrumentation systems by these new technology transmitters. Equipment characterization was accomplished to determine interference potential of the proposed new transmitters and susceptibility of several GPS TSPI receivers. Several filtering techniques were identified as possible solutions to the anticipated interference problems. Telemetry (TM)/GPS system mockups and laboratory tests of the same were accomplished. Open-air testing was then accomplished to validate laboratory results. Finally, on aircraft tests were accomplished prior to performing any aircraft system modifications. Results of these test efforts are presented for others to consider when planning similar modifications to other platforms.