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1
Lahiri, Basudev. "Split Ring Resonator (SRR) based metamaterials." Thesis, University of Glasgow, 2010. http://theses.gla.ac.uk/1622/.
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Metamaterials are artificial materials that are known to produce extraordinary electromagnetic responses due to their constituent artificially-engineered micro- or nanostructures of dimensions smaller than that of the wavelength of light. The Split ring resonator (SRR) is such a nanostructure that forms the basic unit of a metamaterial. Since the dimensions of the SRRs are required to be smaller than the resonance wavelength, it becomes critical when response is required at the near infrared and optical wavelengths. In this thesis the various properties of the nanoscale SRRs are studied that resonates in the infrared and visible spectrum. The SRRs mentioned in this thesis are made of both aluminium and gold and have been fabricated on silicon and silica substrates using standard electron beam lithography (EBL) techniques. The effect of different metals (Al and Au) on the resonance of SRRs is studied. A substantial shift is reported, in the response of arrays of similarly sized SRRs, made respectively of aluminium and of gold. It is shown that by using aluminium based SRRs instead of gold; the magnetic resonance of SRRs can be shifted into the visible spectrum. The effect of titanium adhesion layers on the properties of SRRs are considered and it is shown that even a 2 nm thin layer of titanium can red-shift the SRR resonance by 20 nm. It is shown, that by adding asymmetry between the geometries of similar sizes SRRs, it is possible to produce a steeper resonance response, thereby increasing the quality factor of the SRRs. This steep response of asymmetric split ring resonators (A-SRRs) are utilised for the optical detection of very thin film organic compounds. It is further shown that by localising the organic compound to specific regions of the A-SRRs, greater enhancement in optical detection could be achieved. Finally, the same property of A-SRRs are utilised for the enhanced detection and differentiation between different DNA strands.
2
Compaleo, Joshua David. "Split Ring Resonator Design for Agricultural Based Applications." Wright State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=wright1452981065.
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3
Wu, Jay-Hsing 1979. "Designs and characterization of switchable microwave electromagnetic bandgap and split-ring resonator structures." Thesis, McGill University, 2007. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103034.
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The design and characterization of both electromagnetic bandgap (EBG) and inter-coupled split-ring resonator (SRR) structures utilized in microwave frequencies were proposed and studied. A new double-stopband EBG structure with a passband region of 14 to 18 GHz was initially constructed by determining the critical structural ratios. To reduce the size of EBG structure, a novel tapered array pattern was introduced. The structural period, the number of slot, and the length of slot were examined and a strong correlation was found between the lowpass cutoff frequency and the center slot length. Non-linearly tapered configuration was applied to enhance the filter performance and its size was only 57% of the conventional EBG structure. Inter-coupled SRR was also examined and utilized as a bandpass filter when it is implemented on the microstrip line for the first time. It was found that the proposed structure can provide a fractional bandwidth of over 68% with an insertion loss of 0.81 dB in the passband region with a device size of 15.5 mm.Chemical bath deposited Cadmium Sulfide (CdS) thin film was applied to the microwave structures to construct switchable filters. The illumination-sensitive CdS thin film's sheet resistance has been demonstrated to be able to switch from 300 to 109 O/square. With the proposed "conductive-islands" implementation, switching of EBG structure's transmission coefficient (S21) was achieved from 31.3 dB to 5.6 dB at 13 GHz. The inter-coupled SRR structure also showed a S21 switching response from 19 dB to 1.5 dB at 5 GHz. Therefore, optically controlled microwave filters were successfully constructed and realized.
Critical contributions in the field of microwave periodic structures are the characterization and the construction of double-stopband structure, linearly and non-linearly tapered array structures, and inter-coupled SRR structures. Vital characteristics and advantages discovered include wide stopband, reduced size, and large fractional bandwidth. Chemical bath deposited CdS thin films were studied to achieve an ultra low sheet resistance and high photosensitivity. Important applications associated with these structures are microwave lowpass/bandpass filters and optically controlled filters.
4
Yasar, Orten Pinar. "Numerical Analysis, Design And Two Port Equivalent Circuit Models For Split Ring Resonator Arrays." Master's thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12611620/index.pdf.
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Split ring resonator (SRR) is a metamaterial structure which displays negative permeability values over a relatively small bandwidth around its magnetic resonance frequency. Unit SRR cells and arrays have been used in various novel applications including the design of miniaturized microwave devices and antennas. When the SRR arrays are combined with the arrays of conducting wires, left handed materials can be constructed with the unusual property of having negative valued effective refractive indices.
In this thesis, unit cells and arrays of single-ring multiple-split type SRR structures are numerically analyzed by using Ansoft&rsquos HFSS software that is based on the finite elements method (FEM). Some of these structures are constructed over low-loss dielectric substrates and their complex scattering parameters are measured to verify the numerical simulation results. The major purpose of this study has been to establish equivalent circuit models to estimate the behavior of SRR structures in a simple and computationally efficient manner. For this purpose, individual single ring SRR cells with multiple splits are modeled by appropriate two-port RLC resonant circuits paying special attention to conductor and dielectric loss effects. Results obtained from these models are compared with the results of HFSS simulations which use either PEC/PMC (perfect electric conductor/perfect magnetic conductor) type or perfectly matched layer (PML) type boundary conditions. Interactions between the elements of SRR arrays such as the mutual inductance and capacitance effects as well as additional dielectric losses are also modeled by proper two-port equivalent circuits to describe the overall array behavior and to compute the associated transmission spectrum by simple MATLAB codes. Results of numerical HFSS simulations, equivalent circuit model computations and measurements are shown to be in good agreement.
5
Jabita, Abdul-Nafiu Abiodun. "Design of Singly Split Single Ring Resonator for Measurement of Dielectric Constant of Materials using Resonant Method." Thesis, Högskolan i Gävle, Avdelningen för elektronik, matematik och naturvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-14747.
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Scientists and engineers measure dielectric constant because it gives them better understanding of materials and helps them to know how to integrate these materials into their design processes;it also helps them to shorten design life cycle,and aside these two functions,it has numerous uses all of which cannot be enumerated in this section.Owing to its usefulness,various measurement methods of dielectric constant of materials have been developed over the years.Each method has its limitations which affect the accuracy of the measurement;these limitations range from frequency,temperature,and mearsurement environment to material under test. In this thesis,four most common methods of measuring dielectric constant were discussed and the most accurate one,the resonant method,was chosen and worked on .The project was executed by making a mathematical analysis of the ring resonator which was later simulated in HFSS to get results which would be comparable to ones obtained in laboratory measurements. The ring was fabricated and taken to the laboratory for measurement.Two monopole antennas were connected to the two ports of a VNA with one antenna serving as the transmitter and the other serving as the receiver. The resonant frequencies obtained were combined with the geometric parameters of the ring resonator and that of the MUT in equations written into MATLAB scripts;this equations were used to extract the dielectric constant of the MUT.
6
Debus, Christian [Verfasser]. "A High-Sensitivity THz-Sensing Technology for DNA Detection with Split-Ring Resonator based Biochips / Christian Debus." München : Verlag Dr. Hut, 2013. http://d-nb.info/1037286987/34.
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7
Ge, Ruisi. "A Dual-Band Antenna Enabled Using a Complimentory Split Ring Resonator (CSRR) Placed in the Ground Plane." Thesis, North Dakota State University, 2019. https://hdl.handle.net/10365/29882.
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The microstrip patch antenna is regarded as one of the key components for compact, low cost RF communications and wireless power techniques. In some instances, there are requirements that a system communicate on a different band than the wireless power harvesting band. To address these multi-frequency, a novel dual-band patch antenna enabled with complementary split ring resonators (CSRRs) is designed and fabricated. This antenna operates at 2.4Ghz and 915 MHz, and the antenna miniaturization is achieved by etching the complementary split ring resonators (CSRRs) in the ground plane. A prototype antenna is fabricated and tested, and measured results are in good agreement with simulations. Furthermore, the influence of the CSRR on the behavior of the antenna is also explored and discussed.
8
Berglund, Martin. "Miniature Plasma Sources for High-Precision Molecular Spectroscopy in Planetary Exploration." Doctoral thesis, Uppsala universitet, Ångström Space Technology Centre (ÅSTC), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-251315.
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The prospect of finding life outside Earth has fascinated mankind for ages, and new technology continuously pushes the boundary of how remote and how obscure evidence we can find. Employing smaller, or completely new, types of landers and robots, and equipping them with miniature instruments would indeed revolutionize exploration of other planets and moons. In this thesis, microsystems technology is used to create a miniature high-precision isotope-resolving molecular spectrometer utilizing the optogalvanic effect. The heart of the instrument, as well as this thesis, is a microplasma source. The plasma source is a split-ring resonator, chosen for its simplicity, pressure range and easily accessible plasma, and modified to fit the challenging application, e.g., by the adding of an additional ground plane for improved electromagnetic shielding, and the integration of microscopic plasma probes to extract the pristine optogalvanic signal. Plasma sources of this kind have been manufactured in both printed circuit board and alumina, the latter for its chemical inertness and for compatibility with other devices in a total analysis system. From previous studies, classical optogalvanic spectroscopy (OGS), although being very sensitive, is known to suffer from stability and reproducibility issues. In this thesis several studies were conducted to investigate and improve these shortcomings, and to improve the signal-to-noise ratio. Moreover, extensive work was put into understanding the underlying physics of the technique. The plasma sources developed here, are the first ever miniature devices to be used in OGS, and exhibits several benefits compared to traditional solutions. Furthermore, it has been confirmed that OGS scales well with miniaturization. For example, the signal strength does not decrease as the volume is reduced like in regular absorption spectroscopy. Moreover, the stability and reproducibility are greatly increased, in some cases as much as by two orders of magnitude, compared with recent studies made on a classical OGS setup. The signal-to-noise ratio has also been greatly improved, e.g., by enclosing the sample cell and by biasing the plasma. Another benefit of a miniature sample cell is the miniscule amount of sample it requires, which can be important in many applications where only small amounts of sample are available. To conclude: With this work, an important step toward a miniature, yet highly performing, instrument for detection of extraterrestrial life, has been taken.
9
Aguilà, Moliner Pau. "Estudio de las propiedades de radiación de partículas resonantes con aplicaciones en sistemas de comunicaciones." Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/402268.
Full textAbstract:
El sector de las radiocomunicaciones ha experimentado un drástico desarrollo estos últimos años. Entre ellos, los sistemas de comunicaciones inalámbricos han sufrido un gran crecimiento en la sociedad moderna motivado por el elevado número de servicios en que se pueden aplicar (por ejemplo radiodifusión, telefonía móvil, posicionamiento por satélite o bien identificación por radiofrecuencia). Esto ha motivado la investigación de nuevos dispositivos de microondas con diferentes y mejores prestaciones. La tendencia más extendida actualmente consiste en utilizar tecnologías planares para la realización de los elementos radiantes (típicamente parches metálicos o dipolos de media longitud de onda), lo que permite obtener diseños de bajo coste y fácilmente integrables con el resto de circuitería impresa. Puesto que estos dispositivos son progresivamente más compactos, un aspecto clave también es la búsqueda de técnicas para reducir las dimensiones finales de las antenas así como mejorar su funcionalidad. Una metodología aplicada ampliamente con anterioridad consiste en cargar las antenas impresas con estructuras resonantes (provenientes del campo de los metamateriales) para reducir su frecuencia de operación así como lograr un funcionamiento multifrecuencia. Recientemente, sin embargo, se ha presentado otra alternativa basada en utilizar un resonador Split Ring Resonator trabajando a la segunda resonancia como elemento radiante puesto que muestra unas propiedades de radiación interesantes en términos de eficiencia de radiación e impedancia de entrada.
El objetivo principal de esta tesis ha sido, por tanto, explotar el comportamiento de esta partícula (y otras configuraciones derivadas) a la segunda frecuencia de resonancia como radiador para mejorar las prestaciones de las antenas planares convencionales en una variedad de aplicaciones. Esto abarca las antenas microstrip, las agrupaciones de antenas y, en último término, las superficies polarizadoras.The radiocommunication sector has suffered a rapid development in recent years. Among them, wireless communications systems have shown a great growth in modern society due to the high number of services in which they can be applied (e.g. radio broadcasting, mobile telecommunications, satellite navigation or radio frequency identification). This has motivated a research of new microwave devices with different and improved features. The current trend is to use planar technologies for the realization of radiating elements (typically metallic patches or half-wavelength dipoles), which allows to obtain low cost designs that can be easily integrated with all the printed circuitry. Since these devices are more and more compact, a key point is also the search for techniques to reduce the final dimensions of the antennas as well as to improve their functionality. A widely applied methodology is to load the printed antennas with resonant structures (coming from the field of metamaterials) to reduce their operating frequency as well as to achieve multifrequency operation. Recently, however, another alternative has been proposed based on using a Split Ring Resonator working at the second resonance as a radiator since it shows interesting radiation properties in terms of its radiation efficiency and input impedance. Therefore the main objective of this thesis has been to exploit the behavior of this resonant particle (and other derived configurations) at the second resonant frequency as a radiating element to improve the performance of conventional planar antennas in a variety of applications. This includes microstrip antennas, antenna arrays and, moreover, polarizer sheets.
10
Rodríguez, Pérez Ana María. "Synthesis of Planar Microwave Circuits based on Metamaterial Concepts through Aggressive Space Mapping." Doctoral thesis, Universitat Politècnica de València, 2015. http://hdl.handle.net/10251/48465.
Full textAbstract:
RF and microwave applications represent one of the fastest-growing segments of
the high performance electronics market, where ongoing innovation is critical.
Manufacturers compete intensively to meet market needs with reduced cost,
size, weight and many other performance criteria demands. Under this scenario,
transmission lines based on metamaterial concepts can be considered a very
interesting alternative to the conventional transmission lines. They are more
compact (compatible with planar manufacturing processes) and present higher
degrees of design flexibility. Furthermore, metamaterial transmission lines can
also provide many other unique properties not achievable with ordinary
transmission lines, such as dispersion or impedance engineering. Nevertheless,
the impact in the industry is still not relevant, mostly due to the complexity of
the related synthesis and design procedures. These procedures are mainly based
on the engineer’s experience, with the help of costly full-wave electromagnetic
(EM) simulators and parameter extraction methods.
The aim of this thesis is to contribute to simplify and speed up the synthesis
and design procedures of artificial transmission lines. In particular, the lines
obtained by periodically loading a conventional transmission line with
electrically small resonators, such as split ring resonators (SSRs) or its
complementary particle (CSRR). The design procedure is automated by using
Space Mapping techniques. In contrast to other alternative methods, real
synthesis is found from the circuit schematic (that provides a given target
response) and without need of human intervention. Some efforts to make the
method practical and useful have been carried out. Given a certain target
response, it is determined whether it can be physically implemented with a
chosen technology, and hence proceeding next to find the synthesis, or not. For
this purpose, a two-step Aggressive Space Mapping approach is successfully
proposed.
In contrast to other methods, the real synthesis is found from certain target
circuit values (corresponding to the equivalent circuit model that characterizes
the structure to be synthesized). Different efforts have been carried out in order
to implement a useful and practical method. Some of them were focused to determine if, given certain circuit parameters (which determine the target
response) and certain given technology specifications (permittivity and height of
the substrate, technology limits), that response is physically realizable
(convergence region). This technique was successfully formulated and it is
known as “Two-Step Aggressive Space Mapping Approach”.
In this work, the latest improvements made till date, from the synthesis of
basic unit cells until different applications and kinds of metamaterial-based
circuits, are presented. The results are promising and prove the validity of the
method, as well as its potential application to other basic cells and more complex
designs. The general knowledge gained from these cases of study can be
considered a good base for a coming implementation in commercial software
tools, which can help to improve its competitiveness in markets, and also
contribute to a more general use of this technology.Rodríguez Pérez, AM. (2014). Synthesis of Planar Microwave Circuits based on Metamaterial Concepts through Aggressive Space Mapping [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/48465
TESIS
11
Bibiano, Brito Davi. "Optimisation d'antennes et de circuits à l'aide des métamatériaux." Phd thesis, Télécom ParisTech, 2010. http://pastel.archives-ouvertes.fr/pastel-00749642.
Full textAbstract:
Les métamatériaux à indice de réfraction négative ont attiré énormément l'attention ces dernières années surtout à cause de leurs propriétés électromagnétiques uniques. Ces matériaux sont des structures artificielles qui présentent des caractéristiques n'étant pas disponibles en matériaux naturels. Récemment, le développement technologique avec de nouvelles techniques de fabrication offrent un grand nombre de nouvelles application et développement de nouveaux matériaux. Il est possible d'obtenir un métamatériau en combinant des structures artificielles périodiquement. Les propriétés uniques du Split Ring Resonator (SRR), les Surfaces à Haute Impédance (HIS), les Surface Sélective en Fréquence (FSS) sont étudiées ainsi que les métamatériaux composés. Il a été démontré avec succès l'utilisation pratique de ces structures dans les circuits et les antennes. Il a été confirmé expérimentalement que les métamatériaux pourrait améliorer la performance des structures considérées dans cette thèse, pour des fréquences où la bande interdite électromagnétique se produit.
12
Sahin, Levent. "Transmission And Propagation Properties Of Novel Metamaterials." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610277/index.pdf.
Full textAbstract:
Metamaterials attracted significant attention in recent years due to their potential to create novel devices that exhibit specific electromagnetic properties. In this thesis, we investigated transmission and propagation properties of novel metamaterial structures. Electromagnetic properties of metamaterials are characterized and the resonance mechanism of Split Ring Resonator (SRR) structure is investigated. Furthermore, a recent lefthanded metamaterial structure for microwave regime called Fishnet-type metamaterial is studied. We demonstrated the left-handed transmission and negative phase velocity in Fishnet Structures. Finally, we proposed and successfully demonstrated novel approaches that utilize the resonant
behavior of SRR structures to enhance the transmission of
electromagnetic waves through sub-wavelength apertures at microwave frequency regime. We investigated the transmission enhancement of electromagnetic waves through a sub-wavelength aperture by placing SRR structures in front of the aperture and also by changing the aperture shape as SRR-shaped apertures. The incident electromagnetic wave is
effectively coupled to the sub-wavelength aperture causing a strong localization of electromagnetic field in the sub-wavelength aperture. Localized electromagnetic wave gives rise to enhanced transmission from a single sub-wavelength aperture. The proposed structures are designed, simulated, fabricated and measured. The simulations and experimental
results are in good agreement and shows significant enhancement of electromagnetic wave transmission through sub-wavelength apertures by utilizing proposed novel structures. Radius (r) of the sub-wavelength aperture is approximately twenty times smaller than the incident
wavelength (r/λ
~0.05). This is the smallest aperture size to wavelength ratio in the contemporary literature according to our knowledge.
13
Hu, Xin. "Some studies on metamaterial transmission lines and their applications." Doctoral thesis, Stockholm : Skolan för elektro- och systemteknik, Kungliga Tekniska högskolan, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10126.
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14
Zvolenský, Tomáš. "Modelování mikrovlnných rezonátorů z metamateriálů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217692.
Full textAbstract:
Práce je věnována modelování mikrovlnných rezonátorů z metamateriálů (materiálů se záporným indexem lomu). V úvodu je rozebráno, co metamateriály jsou, jak se vytvářejí a které jejich vlastnosti jsou podstatné při návrhu rezonátorů. Následuje návrh planárního rezonátoru z metamateriálů. Pro tento účel byly naprogramovány funkce počítající rozměry jednotlivých součástí struktury. Simulace navržené struktury probíhala v programu Zeland IE3D. Simulované struktury byly optimalizovány s ohledem na požadované kmitočty rezonance. První rezonátor sestával z jedné elementární buňky, druhý ze dvou buněk, naladěných na rozdílné kmitočty. Rezonátory byly vyrobeny a experimentálně byly ověřeny jejich vlastnosti.
15
Lalj, Hicham. "Conception et caractérisation de filtres et systèmes antennaires reconfigurables chargés par des résonateurs Métamateriaux sub-longueurs d’onde." Thesis, Rennes, INSA, 2014. http://www.theses.fr/2014ISAR0022/document.
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Les structures de base de méta-matériaux nourrissent une alternative technologique prometteuse qui vise à répondre à de nouvelles contraintes de miniaturisation et de performances radioélectriques des systèmes reconfigurables à bas coût.Les travaux de cette thèse reposent sur l’association des cellules Métamateriaux unitaires sub-longueurs d’ondes miniatures et agiles, selon des conditions d’excitation électromagnétique en champ proche, à des dispositifs micro-ondes planaires afin de réaliser de nouvelles structures de filtres et de systèmes antennaires reconfigurables.Après une présentation de l’état de l’art, sur à la fois le concept des Métamateriaux micro-ondes et des modèles de filtres et d’antennes à base des Métamateriaux, nos travaux proposent ensuite sur quatre orientations. La première a trait à l’ingénierie de conception et de simulation électromagnétique des cellules unitaires Métamateriaux, ainsi qu’à l’étude de la miniaturisation et de l’agilité des paramètres électriques.La deuxième orientation est consacrée à la réalisation de nouveaux modèles de filtres agiles basés sur le chargement d’une ligne microruban par des résonateurs sub-longueurs d’onde. Deux modèles de filtres sont développés et validés expérimentalement. Le premier concerne un filtre coupe bande basée sur l’association d’une ligne microruban à des résonateurs de type SRR. Selon le même modèle, un filtre passe bande basé sur une ligne microruban associée à deux cellules résonantes à deux fréquences différentes est proposé. Le deuxième modèle concerne un filtre coupe bande à base d’une ligne microruban chargée par des cellules CSRR, une étude de miniaturisation de ce modèle a été présentée et utilise aussi bien l’optimisation des paramètres géométriques qu’électriques ; un facteur de réduction de 5 est obtenu par rapport au filtre coupe bande de base. Les techniques d’agilité étudiées sont basées sur le chargement de la cellule par des éléments électroniques actifs tels que les diodes PIN et Varactor qui sont logés en des positions appropriées. Les résultats obtenus ont montré une variation intéressante des paramètres du filtre en fonction de la tension de polarisation des diodes.La troisième orientation de la thèse vise à introduire de nouveaux modèles d’association en champ proche entre une antenne monopole ULB et des cellules Métamateriaux de type SRR et CSRR. Ces nouveaux modèles ont pour objectif de répondre à des verrous technologiques en termes de reconfigurabilité spectrale tout en préservant le caractère faible encombrement de l’antenne. Le premier modèle proposé concerne une antenne monopole associée à des cellules SRR imprimées sur le substrat à proximité de la ligne d’alimentation de l’antenne. Les résultats théoriques et expérimentaux confirment le comportement coupe bande autour de la fréquence de résonance de la cellule, et une stabilité des performances de rayonnement sur le reste de la bande passante de l’antenne de référence. Pour Le deuxième modèle, le monopole rayonnant est directement chargé par les cellules SRR et CSRR. Après optimisation des conditions d’alimentation des cellules, les résultats de simulation confirment à la fois le comportement coupe bande autour de la fréquence de résonance de la cellule et la stabilité de rayonnement.La dernière orientation concerne la réalisation de deux nouveaux systèmes antennaires à multi contraintes fréquentielles, pour le besoin de la Radio cognitive. Le premier système est basé sur une antenne monopole et des cellules SRR agiles. Les résultats de mesure et de simulation ont montré l’obtention d’un comportement ULB avec des deux bandes filtrées reconfigurables. Le deuxième nouveau système tente de répondre aux exigences antennaires de la technologie radio cognitive. L’ensemble des résultats obtenus ont montré une flexibilité de passage du mode antenne-capteur (ULB) à une antenne de communication à bande étroite reconfigurableThe basic structures of metamaterial nourish a promising alternative technology, which aims to meet new demands of miniaturization and performance of reconfigurable radio systems. The work of this thesis based on the combination of miniature and agile cells, according to excitation conditions in the near-field electromagnetic, and a planar microwave devices to achieve a new structure of filters and reconfigurable antenna systems. After a presentation of the state of the art, on both the concept of metamaterial microwave and models of filters and antennas based on metamaterial, our work then propose four orientations. The first relates to the engineering design and simulation of electromagnetic metamaterial unit cells, and the study of miniaturization and agility of the electrical parameters. The second orientation is devoted to the realization of new models of filters based on loading the microstrip line with metamaterial resonators. Two filter models are developed and validated experimentally. The first concerns a band stop filter based on the combination of a microstrip line and SRR resonator. According to the same model, a band-pass filter based on a microstrip line associated with two cells in two different resonant frequencies is proposed. The second model provides a band stop filter based on a microstrip line loaded with CSRR cells, a study miniaturization of this model was presented and used both geometric and electrical optimization of parameters. The agility techniques studied are based on the loading of the cell by active electronic elements such as PIN and varactor diodes which are inserted in appropriate positions. The obtained results showed an interesting variation of the filter parameters. The third focus of the thesis is to introduce new models of association in the near-field, between UWB monopole antenna and metamaterial. The first model relates a monopole antenna associated with SRR cells printed in the substrate close to the excitation line of the antenna. The theoretical and experimental results confirm the behavior stop band around the cell resonance frequency, and a stable performance of radiation in the rest of the reference antenna bandwidth. For the second model the monopole is loaded by the SRRs CSRRs cells. After optimization of the cells excitation conditions, the simulation results confirm both the stop band behavior around the cell resonance frequency and the stability of the radiation pattern. The latest orientation concerns the realization of two new antenna systems with multi frequency constraints for cognitive radio application. The first system is based on a monopole antenna and tunable SRRs cells. The measurement and simulation results show a UWB behavior with two reconfigurable and controllable filtered bands. The second new systems tempt to reply the antennas systems requirements used in the cognitive radio. All results showed a flexibility of switching from antenna-sensor (ULB) to a communication antenna with tunable and controllable narrow band
16
Clark, Alasdair W. "Nanophotonic split-ring resonators as dichroics for molecular spectroscopy." Thesis, University of Glasgow, 2009. http://theses.gla.ac.uk/1302/.
Full textAbstract:
The unique optical properties of metallic nanostructures have enabled the creation of a new generation of ultra sensitive biosensors based on vibrational spectroscopy. Through strict engineering of structural morphology, a nanometal’s free electrons can be tuned to resonate at a particular frequency, resulting in amplification and confinement of the electromagnetic field around certain areas of the structure. Molecules situated within these areas experience a greater degree of polarisation due to the oscillating plasmon field, a phenomena which, when combined with resonance Raman spectroscopy, has been shown to enable single molecule detection.1, 2 This thesis describes the fabrication and plasmonic characterisation of Au and Ag circular nano split-ring resonators using a combination of electron beam lithography, finite difference time domain simulation and transmission spectroscopy. Through alteration of ring radius, arc length, wall width, metal thickness and metallic composition it is shown that the asymmetric split-ring structures exhibit a multi-modal, polarisation dependent plasmonic response that can be tuned over several microns. Such a response enables these geometries to be employed as novel multi-wavelength biosensors via surface enhanced Raman spectroscopy and surface enhanced resonance Raman spectroscopy. This work goes on to demonstrate that by using electron beam lithography to manipulate the nano-scale geometry of Ag split-ring resonators, their optical properties can be tuned such that the structures exhibit two independently addressable, high frequency plasmon resonance modes for SERRS. In a series of sensing experiments it is shown that this tailored, multi-modal, polarisation dependent activity enables the split-rings to act as discriminating sensors, with each resonance tuned for a particular sensing purpose. Ultimately the structures are used as multi-wavelength, multi-analyte DNA SERRS sensors, with each resonance tuned both to the absorption wavelength of a differently coloured Raman reporter molecule and its corresponding laser excitation wavelength. In doing so, the ability of each resonance to independently sense clinically relevant concentrations of single DNA strand types from within a mixed population on the sensor surface is demonstrated.
17
Noori, Ahmed Sabah. "Tunable microwave filters based on dielectric split ring resonators." Thesis, University of Birmingham, 2018. http://etheses.bham.ac.uk//id/eprint/8651/.
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This thesis investigates a new type of microwave tunable filter; the filter is designed based on a new type of resonator called Dielectric Split Ring Resonator (Dielectric-SRR). The new tunable filter is utilised to tune the filter bandwidth at about 2.3 GHz. This bandwidth tuning is achieved by rotating the filter resonators and without adding tuning elements such as screws or varactor diodes. In the measurement the filter resonators are rotated by hand. This thesis also investigates the new Dielectric-SRRs in term of their losses and unloaded quality factor. These new microwave resonators are designed with a configuration similar to the conventional metal Split Ring Resonators (Metal-SRR), but made from dielectric material of high dielectric constant. The new Dielectric-SRR achieved unloaded quality factor \(Q\)\(_u\) 3 times higher than the \(Q\)\(_u\) value of the conventional Metal-SRR. Besides the new tunable filter, a new class of non-tunable filter with two different configurations is investigated. The two filters are designed based on the new Dielectric-SRRs, the first design is 3rd order Chebyshev filter, and the second is a 4th order filter with two symmetric transmission zeros. The non-tunable filters achieved excellent measured performance, and good agreement between measurements and simulations.
18
Ekmekci, Evren. "Design, Fabrication And Characterization Of Novel Metamaterials In Microwave And Terahertz Regions: Multi-band, Frequency-tunable And Miniaturized Structures." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612730/index.pdf.
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This dissertation is focused on the design, fabrication, and characterization of novel metamaterials in microwave and terahertz regions with the following outcomes:
A planar µ-negative metamaterial structure, called double-sided SRR (DSRR), is proposed in the first part of this study. DSRR combines the features of a conventional split ring resonator (SRR) and a broadside-coupled SRR (BC-SRR) to obtain much better miniaturization at microwave frequencies for a given physical cell size. In addition to DSRR, double-sided multiple SRR (DMSRR), double-sided spiral resonator (DSR), and double-sided U-spiral resonator (DUSR) have been shown to provide smaller electrical sizes than their single-sided versions under magnetic excitation. In the second part of this dissertation, a novel multi-band tunable metamaterial topology, called micro-split SRR (MSSRR), is proposed. In addition to that, a novel magnetic resonator structure named single loop resonator (SLR) is suggested to provide two separate magnetic resonance frequencies in addition to an electric resonance in microwave region. In the third part, two different frequency tunable metamaterial topologies called BC-SRR and gap-to-gap SRR are designed, fabricated and characterized at terahertz frequencies with electrical excitation for the first time. In those designs, frequency tuning based on variations in near field coupling is obtained by in-plane horizontal or vertical displacements of the two SRR layers. The values of frequency shifts obtained for these tunable metamaterial structures are reported to be the highest values obtained in literature so far. Finally, in the last part of this dissertation, novel double-sided metamaterial based sensor topologies are suggested and their feasibility studies are presented.
19
Javora, Petr. "Návrh planárních anténních struktur z metamateriálů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218023.
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The thesis deals with basic principles of metamaterials, which exhibit unusual properties in microwave applications (e.g., negative permittivity and permeability). Different type of metamaterial antennas and parameters of such antennas are described in the thesis.
20
Brito, Davi Bibiano. "Metamaterial inspired improved antennas and circuits." Universidade Federal do Rio Grande do Norte, 2010. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15152.
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Previous issue date: 2010-12-06Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior
Metamaterials exhibiting negative refraction have attracted a great amount of attention in recent years mostly due to their exquisite electromagnetic properties. These materials are artificial structures that exhibit characteristics not found in nature. It is possible to obtain a metamaterial by combining artificial structures periodically. We investigated the unique properties of Split Ring Resonators, High impedance Surfaces and Frequency Selective Surfaces and composite metamaterials. We have successfully demonstrated the practical use of these structures in antennas and circuits. We experimentally confirmed that composite metamaterial can improve the performance of the structures considered in this thesis, at the frequencies where electromagnetic band gap transmission takes place
21
Limaye, Aparna U. "Size reduction of microstrip antennas using left-handed materials realized by complementary split-ring resonators /." Link to online version, 2006. https://ritdml.rit.edu/dspace/handle/1850/2428.
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Pasakawee, Sarinya. "Left-handed metamaterials realized by complementary split-ring resonators for RF and microwave circuit applications." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/lefthanded-metamaterials-realized-by-complementary-splitring-resonators-for-rf-and-microwave-circuit-applications(ee526cec-0c7a-4733-8534-7023c364f786).html.
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A new equivalent circuit of left-handed (LH) microstrip transmission line loaded with Complementary split-ring resonators (CSRRs) is presented. By adding the magnetic coupling into the equivalent circuit, the new equivalent circuit presents a more accurate cutoff frequency than the old one. The group delay of CSRRs applied with microstrip transmission line (TL) is also studied and analyzed into two cases which are passive CSRRs delay line and active CSRRs delay line. In the first case, the CSRRs TL is analyzed. The group delay can be varied and controlled via signal frequency which does not happen in a normal TL. In the active CSRRs delay line, the CSRRs loaded with TL is fixed. The diodes are added to the model between the strip and CSRRs. By observing a specific frequency at 2.03GHz after bias DC voltages from -10V to -20V, the group delay can be moved from 0.6ns to 5.6ns. A novel microstrip filter is presented by embedding CSRRs on the ground plane of microstrip filter. The filter characteristic is changed from a 300MHz narrowband to a 1GHz wideband as well as suppression the occurrence of previous higher spurious frequency at 3.9GHz. Moreover, a high rejection in the lower band and a low insertion loss of <1dB are achieved.Finally, it is shown that CSRRs applied with planar antenna can reduce the antenna size. The structure is formed by etching CSRRs on the ground side of the patch antenna. The meander line part is also added on the antenna patch to tune the operation frequency from 1.8GHz downward to 1.73GHz which can reduce the antenna size to 74% of conventional patch antennas. By using the previous antenna structure without meander line, this proposed antenna can be tuned for selecting the operation frequency, by embedding a diode connected the position between patch and ground. The results provide 350MHz tuning range with 35MHz bandwidth.
23
Seetharaman, Sathya Sai. "Electromagnetic interactions in one-dimensional metamaterials." Thesis, University of Exeter, 2018. http://hdl.handle.net/10871/33746.
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Metamaterials offer the freedom to tune the rich electromagnetic coupling between the constituent meta-atoms to tailor their collective electromagnetic response. Therefore, a comprehensive understanding of the nature of electromagnetic interactions between meta-atoms is necessary for novel metamaterial design, which is provided in the first part of this thesis. The subsequent work in the thesis applies the understanding from the first part to design and demonstrate novel one-dimensional metamaterials that overcome the limitations of metamaterials proposed in literature or exhibit electromagnetic responses not previously observed. Split-ring Resonators (SRRs) are a fundamental building block of many electromagnetic metamaterials. In the first part of the work in this thesis, it is shown that bianisotropic SRRs (with magneto-electric cross-polarisation) when in close proximity to each other, exhibit a rich coupling that involves both electric and magnetic interactions. The strength and nature of the coupling between two identical SRRs are studied experimentally and computationally as a function of their separation and relative orientation. The electric and magnetic couplings are characterised and it is found that, when SRRs are close enough to be in each other's near-field, the electric and magnetic couplings may either reinforce each other or act in opposition. At larger separations retardation effects become important. The findings on the electromagnetic interactions between bianisotropic resonators are next applied to developing a one-dimensional ultra-wideband backward-wave metamaterial waveguide. The key concept on which the metamaterial waveguide is built is electro-inductive wave propagation, which has emerged as an attractive solution for designing backward-wave supporting metamaterials. Stacked metasurfaces etched with complementary SRRs (CSRRs) have also been shown to exhibit a broadband negative dispersion. It is demonstrated through experiment and numerical modeling, that the operational bandwidth of a CSRR metamaterial waveguide can be improved by restricting the cross-polarisation effects in the constituent meta-atoms. The metamaterial waveguide constructed using the modified non-bianisotropic CSRRs are found to have a fractional bandwidth of 56.3\% which, based on a thorough search of relevant literature, is the broadest reported value for an electro-inductive metamaterial. A traditional coupled-dipole toy-model is presented as a tool to understand the field interactions in CSRR based metamaterials, and to explain the origin of their negative dispersion response. This metamaterial waveguide should be of assistance in the design of broadband backward-wave metamaterial devices, with enhanced electro-inductive waveguiding effects. In the final part of the thesis, a one-dimensional metamaterial prototype that permits simultaneous forward- and backward-wave propagation is designed. Such a metamaterial waveguide could act as a microwave analogue of nanoparticle chains that support electromagnetic energy transfer with a positive or a negative dispersion due to the excitation of their longitudinal or transverse dipole modes. The symmetry of the designed hybrid meta-atom permits the co-existence of two non-interfering resonances closely separated in frequency. It is experimentally and computationally shown that the metamaterial waveguide supports simultaneous non-interacting forward- and backward-wave propagation in an overlapping frequency band. The proposed metamaterial design should be suitable for realising bidirectional wireless power transfer applications.
24
Niesler, Fabian Bernd Peter [Verfasser], and M. [Akademischer Betreuer] Wegener. "Nonlinear Optics of Split-Ring Resonators and their Application as a Thermal Detector / Fabian Bernd Peter Niesler. Betreuer: M. Wegener." Karlsruhe : KIT-Bibliothek, 2012. http://d-nb.info/102803105X/34.
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Iyer, Srinivasan. "Effects of surface plasmons in subwavelength metallic structures." Doctoral thesis, KTH, Optik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103613.
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The study of optical phenomena related to the strong electromagnetic response of noble metals (silver (Ag) and gold (Au) being most popular) over the last couple of decades has led to the emergence of a fast growing research area called plasmonics named after 'surface plasmons' which are electron density waves that propagate along the interface of a metal and a dielectric medium. Surface plasmons are formed by the coupling of light to the electrons on the metal surface subject to the fulfillment of certain physical conditions and they are bound to the metal surface. Depending on whether the metallic medium is a continuous film or a structure having dimensions less than or comparable to the wavelength of the exciting light, propagating or localized surface plasmons can be excited. The structure can be either a hole or an arbitrary pattern in a metal film, or a metallic particle. An array of subwavelength structures can behave as an effective homogeneous medium to incident light and this is the basis of a new class of media known as metamaterials. Metallic metamaterials enable one to engineer the electromagnetic response to incident light and provide unconventional optical properties like negative refractive index as one prominent example. Metamaterials exhibiting negative index (also called negative index materials (NIMs)) open the door for super resolution imaging and development of invisibility cloaks. However, the only problem affecting the utilization of plasmonic media to their fullest potential is the intrinsic loss of the metal, and it becomes a major issue especially at visible-near infrared (NIR) frequencies. The frequency of the surface plasmon is the same as that of the exciting light but its wavelength could be as short as that of X-rays. This property allows light of a given optical frequency to be conned into very small volumes via subwave lengthmetallic structures, that can be used to develop ecient sensors, solar cells, antennas and ultrasensitive molecular detectors to name a few applications. Also, interaction of surface plasmons excited in two or more metallic subwavelength structures in close proximity inuences the far-eld optical properties of the overall coupled system. Some eects of plasmonic interaction in certain coupled particles include polarization conversion, optical activity and transmission spectra mimicking electromagnetically-induced transparency (EIT) as observed in gas based atomicsy stems. In this thesis, we mainly focus on the optical properties of square arrays of certain plasmonic structures popularly researched in the last decade. The structures considered are as follows: (1) subwavelength holes of a composite hole-shape providing superior near-eld enhancement such as two intersecting circles (called' double hole') in an optically thick Au/Ag lm, (2) double layer shnets, (3) subwavelength U-shaped particles and (4) rectangular bars. The entire work is based on electromagnetic simulations using time and frequency domain methods. Au/Ag lms with periodic subwavelength holes provide extraordinarily high transmission of light at certain wavelengths much larger than the dimension of the perforations or holes. The spectral positions of the maxima depend on the shape of the hole and the intra-hole medium, thereby making such lms function as a refractive index sensor in the transmission mode. The sensing performance of the double-hole geometry is analyzed in detail and compared to rectangular holes. Fishnet metamaterials are highly preferred when it comes to constructing a NIM at optical frequencies. A shnet design that theoretically oers a negative refractive index with least losses at telecommunication wavelengths (1.4 1.5 microns) is presented. U-shaped subwavelength metallic particles, in particular single-slit split-ring resonators (SSRRs), provide a large negative response to the magnetic eld of light at a specic resonance frequency. The spectral positions of the structural resonances of the U-shaped particle can be found from its array far field transmission spectrum at normal incidence. An effort is made to clarify our understanding of these resonances with the help of localized surface plasmon modes excited in the overall particle. From an application point of view, it is found that a planar square array of SSRRs eectively functions as an optical half-wave waveplate at the main resonance frequency by creating a polarization in transmission that is orthogonal to that of incident light. A similar waveplate eect can be obtained purely by exploiting the near-eld interaction of dierently oriented neighbouring SSRRs. The physical reasons behind polarization conversion in dierent SSRR-array systems are discussed. A rectangular metallic bar having its dipolar resonance in the visible-NIR is called a nanoantenna, owing to its physical length in the order of nanometers. The excitation of localized surface plasmons, metal dispersion and the geometry of the rectangular nanoantenna make an analytical estimation of the physical length of the antenna from the desired dipolar resonance dicult. A practical map of simulated resonance values corresponding to a variation in geometrical parameters of Au bar is presented. A square array of a coupled plasmonic system comprising of three nanoantennas provides a net transmission response that mimicks the EIT effect. The high transmission spectral window possesses a peculiar dispersion profile that enables light with frequencies in that region to be slowed down. Two popular designs of such plasmonic EIT systems are numerically characterized and compared.QC 20121017
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Sousa, Neto Marinaldo Pinheiro de. "Um estudo de metamaterial em antenas de microfita." Universidade Federal do Rio Grande do Norte, 2014. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15247.
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Previous issue date: 2014-04-25Universidade Federal do Rio Grande do Norte
Metamaterials have attracted a great attention in recent years mostly due to their electromagnetic properties not found in nature. Since metamaterials began to be synthesized by the insertion of artificially manufactured inclusions in a medium specified host , it provides the researcher a broad collection of independent parameters such as the electromagnetic properties of the material host. In this work was presents an investigation of the unique properties of Split Ring Resonators and compounds metamaterials was performed. We presents a theoretical and numerical analysis , using the full-wave formalism by applying the Transverse Transmission Line - LTT method for the radiation characteristics of a rectangular microstrip antenna using metamaterial substrate, as is successfully demonstrated the practical use of these structures in antennas. We experimentally confirmed that composite metamaterial can improved the performance of the structures considered in this thesis
Os metamateriais tem atra?do uma grande aten??o nas ?ltimas d?cadas, principalmente devido as suas propriedades eletromagn?ticas n?o encontradas na natureza. Desde que os metamateriais passaram a ser sintetizados atrav?s da inser??o de inclus?es artificialmente fabricadas num meio hospedeiro especificado, isto propicia ao pesquisador uma larga cole??o de par?metros independentes, tais como as propriedades eletromagn?ticas do material hospedeiro. Neste trabalho foi realizada uma investiga??o das propriedades ?nicas dos Ressoadores em Anel Partido (Split Ring Ressonators - SRR) e dos metamateriais compostos. Apresentou-se uma an?lise te?rica e num?rico-computacional, utilizando o formalismo de onda completa atrav?s da aplica??o do m?todo da Linha de Transmiss?o Transversa LTT, para as caracter?sticas ressonantes de uma antena de microfita com patch retangular utilizando substrato metamaterial, assim como ? demonstrado com sucesso ? utiliza??o pr?tica dessas estruturas em antenas. Esta utiliza??o pr?tica ? confirmada experimentalmente
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Ayad, Houssam. "Antenna Performance Control using Metamaterials." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENT013/document.
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Le travail de cette thèse est en rapport avec les métamatériaux et ses applications. Tout d’abord, un état de l’art est dressé en présentant leur évolution depuis leur apparition en 19ème siècle jusqu’au nos jours. Les notions sur les milieux chirale, bi-anisotrope, cristaux photoniques et quelques applications dans ces milieux sont données. Ensuite, nous présentons les équations classiques de Maxwell dans les milieux complexes. L’effet bi-anisotrope dans les métamatériaux est ensuite validé par l’extraction des paramètres caractéristiques du matériau main gauche (LHM). La validation a été faite en utilisant deux types différents du résonateur avec inclusion (SRR). Les métamatériaux sont également étudiés comme des cristaux photoniques quand les dimensions utilisées sont de l’ordre de la longueur d’onde correspondant.De plus, les résonateurs SRR et multi-SRR sont analysés du point de vue analytique et électromagnétique afin d’extraire leur fréquence de résonance. Par conséquent, ces composants peuvent être introduits dans différents types de conception; La surface conductrice magnétique artificielle (AMC) illustre un cas explicite et efficace de ces derniers. Une antenne dipôle, placée sur cette surface à la place d’un plan de masse conventionnel, a été étudiée comme une application des métamatériaux. Les résultats relatifs sur la directivité, le gain et le coefficient de réflexion montrent une nette amélioration. Une antenne multi-bandes, comme une autre application des métamatériaux, a également été conçue et simulée. Le résonateur SRR est inséré dans l’antenne de départ afin de créer une autre résonance, et par conséquent une autre bande est ainsi crééeThe work in this thesis deals with metamaterials, its components and applications. A historical overview about these materials, features and researches in the domain are presented. Chiral media, binaisotropic materials and photonic crystals are also studied in order to visualize physics behind metamaterials.Electromagnetic properties in complex media are widely investigated. Starting from Maxwell’s equations, bi-anisotropic materials and their effect are deeply analyzed whereas two types of Split Ring Resonator (SRR) are treated to determine constitutive parameters of Left Handed Materials (LHM). The metamaterials are also studied as photonic crystals since the effective medium approach is not applicable when the dimensions of the inclusions tend to the operating wavelength.Moreover, SRRs and Multi SRRs are synthesized analytically and electromagnetically in order to extract their resonant frequencies. Consequently, these components could be introduced in any design; Artificial Magnetic Conductor (AMC) surface is an efficient case. Thus, a low profile antenna positioned over such surface is examined as an application of metamaterials. The results of directivity, gain and reflection coefficient are of great importance and affirm the employing of metamaterials in such applications. A dual band PCB antenna, as another application of metamaterials, is designed and simulated. The SRR element studied in the previous chapters is used as the trap which inserted in the arm of the antenna in order to create another resonance, and consequently another band is created
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Ates, Kazim Ozan. "Theoretical Investigation Of Metamaterials: Srr Structures And Periodic Arrays Of Thin Conducting Wires." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609485/index.pdf.
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In recent years, there has been an increasing interest on left handed metamaterials because of their possible innovative applications. The pioneer study introducing such materials was brought out by V. G. Veselago in 1968 [1]. In his work, Veselago proposed a medium having simultaneously negative electric permittivity and magnetic permeability and investigated its electromagnetic characteristics. He found out that the electric field, magnetic field and the propagation vector form a left handed triplet, thus named such materials as &ldquoLeft Handed Materials&rdquo
. Despite the significance of Veselago&rsquo
s inferences, the metamaterial theory stayed dormant for nearly 30 years. Towards the end of 1990s, the physically realizable left handed materials were built as the combination of two periodical structures
Split Ring Resonators (SRRs) and metallic thin wire arrays [4-5]. In this thesis, electrical and magnetic characteristics of the left handed metamaterials are theoretically investigated by using the analytical models for their permittivity and permeability functions with respect to frequency. For this purpose, first, two basic metamaterial structures
the Split Ring Resonators and Thin Metallic Wire Arrays are studied individually and their electrical and magnetic characteristics are examined. Finally, the composite left handed structure containing both SRRs and thin wires is studied to investigate the resulting simultaneous resonance properties and to estimate their overall effective permeability and permittivity functions.
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Chiou, Min-Da, and 邱敏達. "Split-Ring Resonator Structure Electrically Small Antenna." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/61643085342148674569.
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碩士國立臺灣大學
電信工程學研究所
99
This paper proposes two antenna designs of planar split ring resonator (SRR) structure fed by coplanar grounded waveguide. In the first design, we use a small loop to feed the SRR structure antenna, so the bandwidth and efficiency are improved from the precious design. In order to eliminate ground size effect, we propose another design, using a slot to present SRR structure. Both designs were designed to match to 50 ohms, and the geometric dimensions are both at about (1⁄20) λ_0×(1⁄20) λ_0. To compare with well-proposed designs, we use the quality factor and the Chu-limit to analyze various electrically small antennas which work on separate frequency; therefore, we obtain the advantage of our design comparing to the well-proposed designs. Since various definitions of Quality factor and various derivations of Chu-limit under different assumptions have been considered at previous works, we direction different researches, and unify the definition on quality factor to their results. Moreover, by summarizing these results, we illustrate the physical meaning of these hypotheses, thus some novel perspectives on designing electrically small antenna are proposed.
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Chung, Tsung-Lin, and 鍾宗霖. "Nonlinear enhancement of vertical split ring resonator." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/e7w85x.
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碩士國立臺灣大學
物理學研究所
106
Nonlinear optics has been developed for several decades to understand the responses from interaction between electrons and strong incident light. So far, there are many practical applications by using the concept of nonlinear optics, such as ultrafast pulse laser, tunable light source (optical parametric oscillator), super resolution imaging. Recently, with the development of nanophotonics, metamaterial gradually attracts wide attentions. Metamaterial is an artificial structure in sub-wavelength scale. Because of its unique optical properties, it can be used for light manipulation, including the phase, polarization and electromagnetic field of light. In ordinary nonlinear optics, when a light impinges onto a nonlinear crystal, the nonlinear effects are from the intrinsic properties of the material. The whole nonlinear process must follow the conservation law of energy and momentum. However, in the sub-wavelength region, metamaterial offers a unique platform to interact with incident light. By arranging nano-structures in a specific orientation or introducing multi-resonant system, metamaterial is able to generate nonlinear light. In this work, we compare the second harmonic generation (SHG) response between vertical split ring resonator (VSRR) and planar split ring resonator (SRR). The finite element method (FEM) simulation is used to analyze both fundamental and nonlinear optical properties of VSRR and SRR. From simulation results, we found VSRR can simultaneously couple with incident electric and magnetic field, so it has a stronger fundamental field confinement compared to SRR. We assume this property leading VSRR has stronger SHG signal than SRR. On the other hand, VSRR has a dual SHG polarization states while SRR only has one, which is additional advantage of VSRR. From experiment results, the SHG signal of VSRR is about 3 times as stronger than those of planar SRR. The result proves VSRR has a potential in generating and manipulating SHG in the future.
31
Chen, Jiun-Peng, and 陳君朋. "Split-Ring Resonator Antennas for Wireless Communication Applications." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/19142391871654705459.
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博士國立臺灣大學
電信工程學研究所
102
Split-ring resonators (SRRs) are proposed for miniaturized slot antenna, wireless sensor networks (WSNs) application, circularly polarized antenna, and tag antenna of radio frequency identification (RFID). From the perspective of the history and structure introduce the SRRs in Chapter 2. Chapter 3 addresses a slot dipole antenna fed by a coplanar waveguide (CPW) with SRRs. When resonators are placed at different positions of the slot with all other parameters unchanged, the resonant frequency can be changed. The resonant frequency of the slot can be lowered significantly when SRRs are placed close to the central feeding CPW line. By the similar concept introduced in Chapter 3, a slot antenna using capacitive load realized by SRRs is proposed as the node antenna in Chapter 4. The slot antenna fed by a microstrip line is proposed as an easy method to conjugate match to the chips using lumped elements. In Chapter 5 and Chapter 6, a spirally complementary split-ring resonators (CSRRs) antenna with circular polarization (CP) and a compact strip dipole coupled SRR antenna are proposed for RFID reader and tag applications, respectively. In reader applications, the size of circular antenna is compact, which is very suitable for the ultra-high frequency (UHF) handheld RFID reader system. In tag applications, the tag antenna has a simple and uniplanar structure to conjugate match to the chip by detail design process. The input impedance of tag antenna is measured by thru-reflect-line (TRL) calibration technique and probe technique. The radiation patterns are measured and compared to the minimum power transmitted by the reader. Good agreement between simulation and experiment is obtained.
32
Hsu, Wei-Lun, and 許維綸. "Split-ring resonator based metasurface: Light Manipulation and Applications." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/59821910375179374632.
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博士國立臺灣大學
物理研究所
104
Metasurface is a kind of artificial material constructed by metal nanostructure with well-designed patterned on its surfaces has shown to possess unusual abilities to manipulate light. In this dissertation, two types of split-ring resonators based metasurface have been designed and investigated. Recently, we have designed the 3D nanostructures, namely vertical split-ring resonators (VSRRs), which opens up another degree of freedom in the metasurface design. VSRR-based metasurface is able to anomalous steering reflection of a wide range of angles can be accomplished with high extinction ratio using the finite-difference-time-domain simulation. On the other hand, VSRR-based metasurface can be made with roughly half of the footprint compared to that of rods-based metasurface, enabling high density integration of metal nanostructures. At present, proposed functions of metasurface-based devices are mostly oriented to bright-field but not dark-field. We first propose and analyze an asymmetric split-ring-based metasurface with ability of edge-emission at visible region under dark-field environment. By changing periodic distance between two adjacent split-ring elements, the mode with edge-emission can be controlled. It can be observed under dark-field measurement with property of spectral-dependent spatial variation. The feasibility of proposed design has been demonstrated by the electromagnetic numerical simulation and dark-field measurement. The broadband phenomena of edge emission have been observed from 650 to 900 nm.
33
Hsieh, Yuan-Hsiang, and 謝元翔. "Mechanical Vibration Detection Using a Complementary Split-Ring Resonator." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/56345440203466473675.
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碩士國立中興大學
物理學系所
104
We demonstrate the movement measurement of a metal film or a metal beam by monitoring the change of resonance frequency of a nearby complementary split-rings resonator (CSRR). The CSRR has a resonance frequency of 3GHz and a quality factor of about 10. When the metal flim approaches the CSRR vertically, the frequency change in CSRR resonance follows an exponential dependence on the spacing between them. This freqeuncy change persists by reducing the metal film thickness down to 50nm . Our method allows us to estimate the actual mechanical vibration amplitude on the range of 0.4mm , which agrees well with that obtained by using commercial laser displacement meter. When set the metal film at a spacing of 0.4 mm, our setup yield a movement sensitivity of 0.16 nm/√Hz. We also demonstrate how the mechanical resonances of a clamped PI flim can be investigated with our method. For reducing the back-action to quantum mechanical systems, we set up a system consisting of a pulse mechanical driving and a pluse readout. This pulse driving-and-readout system allows us to estimate the damping ratio of a metal beam vibration.
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Albishi, Ali. "Detection of Sub-Millimeter Surface Cracks using Complementary Split-Ring Resonator." Thesis, 2012. http://hdl.handle.net/10012/6827.
Full textAbstract:
Many interesting ideas have emerged from research on electromagnetic eld interactions
with di erent materials. Analyzing such interactions has extracted some essential proper-
ties of the materials. For example, extracting constitutive parameters such as permittivity,
permeability, and conductivity, clari es a material's behavior. In general, the electromag-
netic eld interacts with materials either in the far- eld or near- eld of a source. This
study focuses on the principle of near- eld microwave microscopy for detection purposes.
Many studies have focused on the use of an electrically small resonator, such as a
split-ring resonator (SRR) and a complementary split-ring resonator (CSRR), to act as a
near- eld sensor for material characterization and detection. At the resonance frequency,
the electric and magnetic energy densities are enhanced dramatically at certain locations
in the resonator. Any disturbance of the eld around such a resonator with a material
under test causes the resonance frequencies to exhibit a shift that is used as an indicator
of the sensor sensitivity. In this thesis, a single CSRR is used as a sensing element for
detecting cracks in metal surfaces.
Many microwave techniques have been developed for crack detection. However, these
techniques have at least one of the following drawbacks: working at high frequencies,
measurement setup complexity and cost, and low sensitivity. The rst part of this thesis
presents a new sensor based on the complementary split-ring resonator (CSRR) that is used
to detect sub-millimeter surface cracks. The sensing mechanism is based on perturbing the
electromagnetic eld around an electrically small resonator, thus initiating a shift in the
resonance frequency. Investigation of the current distribution on a CSRR at the resonance
frequency shows the critical location at which the enhanced energy is concentrated. In
addition, the current distribution demonstrates the sensing element in the CSRR. The
sensor is simple to fabricate and inexpensive, as it is etched-out in the ground plane of
a microstrip-line using printed circuit board technology. The microstrip-line excites the
CSRR by producing an electric eld perpendicular to the surface of the CSRR. The sensor
exhibits a frequency shift of more than 240 MHz for a 200 m crack.
In the second part of this thesis, the sensitivity of the sensor is increased by lling
the same crack with a dielectric material such as silicon oil. While using CSRR to scan a
block with 200 m wide and 2 mm depth dielectric lled crack, the resonance frequency
of the sensor shifts 435 MHz more than a case scanning a solid aluminum. Finally, the
total Inductance of a CSRR for miniaturizing purposes is increased using either lumped or
distributed elements. In this thesis, the designs and the results are validated experimentally
and numerically.
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Lai, Lian-Shing, and 賴良星. "Physical properties of YBCO microstrip ring resonator with a split gap." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/17287449071313649079.
Full textAbstract:
碩士國立交通大學
電子物理系
89
The thesis can be divided into three parts. The first is to investigate the microwave properties of high-Tc superconductor ring resonators with various split gap structures. The second part is to use the microwave data of wave impedance, from which the important physical parameters such as Q values, surface impedance, penetration depth and energy gap, have been deduced. The third part attempts to delineate the physical properties of YBCO thin films with various oxygen contents. A detailed process of fabrication of the epitaxial YBCO thin films as well as the microwave ring resonators will be described at first. Using these resonators the generation of the frequency response can be justified by the computer simulation of Ansoft software, in which a perfect conductor, instead of the superconductor, has been taken. From the experimental observation, the case of the superconducting ring resonator appears the resonate frequency as same as that in the conductor. Although both of them have the behavior of the same frequency response, it has possessed the Meissner effect for the superconductor. Incidentally their resonate frequencies are determined by their own boundary conditions. Finally a number of salient results in the microwave measurement allow us to get several important parameters, with which the basic nature of the high-Tc superconductivity in the underdoped case can be elucidated. For instances, the energy gap 2Δ0/kBTc=8±0.2 and Fermi liquid correction factor <1, can be yielded. Moreover, the reduced temperature T/Tc dependence of the superfluid density is shown to be independent of doping concentration, which reflects a fact that the Cu-O chain in the YBCO material is irrelevant in the consideration of superconductor properties, and the pairing mechanism occurs on the CuO2 planes thoroughly.
36
Huang, Guan-Wei, and 黃冠維. "Study of Split-Ring Resonator on the Isolation of Antenna Systems." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/zkqs7e.
Full textAbstract:
碩士義守大學
電子工程學系
104
Mutual coupling has been a critical issue on designing MIMO antenna systems. Mutual coupling produces destructive interference and which reduces the efficiency of the antenna. In this study, split-ring resonator having a band-stop filter characteristics, is placed to between the antenna and the effect of isolation is investigated. The size of the split-ring resonator controls the center frequency of suppression, opening directions and position have effects on the isolation of the antenna system. The measured results show that split-ring resonator not only reduces the mutual coupling of the antenna system, but also enhance gain and radiation efficiency of the antenna.
37
Huang, Da. "Development of Analog Nonlinear Materials Using Varactor Loaded Split-ring Resonator Metamaterials." Diss., 2013. http://hdl.handle.net/10161/7185.
Full textAbstract:
As research in electromagnetics has expanded, it has given rise to the examination of metamaterials, which possess nontrivial electromagnetic material properties such as engineered permittivity and permeability. Aside from their application in the microwave industry, metamaterials have been associated with novel phenomena since their invention, including sub-wavelength focusing in negative refractive index slabs, evanescent wave amplification in negative index media, and invisibility cloaking and its demonstration at microwave frequency with controlled material properties in space.
Effective medium theory plays a key role in the development and application of metamaterials, simplifying the electromagnetic analysis of complex engineered metamaterial composites. Any metamaterial composite can be treated as a homogeneous or inhomogeneous medium, while every unit structure in the composite is represented by its permittivity and permeability tensor. Hence, studying an electromagnetic wave's interaction with complex composites is equivalent to studying the interaction between the wave and an artificial material.
This dissertation first examines the application of a magnetic metamaterial lens in wireless power transfer (WPT) technology, which is proposed to enhance the mutual coupling between two magnetic dipoles in the system. I examine and investigate the boundary effect in the finite sized magnetic metamaterial lens using a numerical simulator. I propose to implement an anisotropic and indefinite lens in a WPT system to simplify the lens design and relax the lens dimension requirements. The numerical results agree with the analytical model proposed by Smith et al. in 2011, where lenses are assumed to be infinitely large.
By manipulating the microwave properties of a magnetic metamaterial, the nonlinear properties come into the scope of this research. I chose split-ring resonators (SRR) loaded with varactors to develop nonlinear metamaterials. Analogous to linear metamaterials, I developed a nonlinear effective medium model to characterize nonlinear processes in microwave nonlinear metamaterials. I proposed both experimental and numerical methods here for the first time to quantify nonlinear metamaterials' effective properties. I experimentally studied three nonlinear processes: power-dependent frequency tuning, second harmonic generation, and three-wave mixing. Analytical results based on the effective medium model agree with the experimental results under the low power excitation assumption and non-depleted pump approximation. To overcome the low power assumption in the effective medium model for nonlinear metamaterials, I introduced general circuit oscillation models for varactor/diode-loaded microwave metamaterial structures, which provides a qualitative prediction of microwave nonlinear metamaterials' responses at relatively high power levels when the effective medium model no longer fits.
In addition to 1D nonlinear processes, this dissertation also introduces the first 2D microwave nonlinear field mapping apparatus, which is capable of simultaneously capturing both the magnitude and phase of generated harmonic signals from nonlinear metamaterial mediums. I designed a C-band varactor loaded SRR that is matched to the frequency and space limitation of the 2D mapper. The nonlinear field generation and scattering properties from both a single nonlinear element and a nonlinear metamaterial medium composite are experimentally captured in this 2D mapper, and the results qualitatively agree with numerical results based on the effective medium model.
Dissertation
38
Pan, Chun-Wei, and 潘俊維. "Microwave Focusing Lenses Synthesized with Positive or Negative Refractive Index Split-Ring Resonator Metamaterials." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/94789536124227375463.
Full textAbstract:
碩士國立交通大學
電信工程研究所
104
Metamaterials had been widely investigated in literature and experiment in recent years, because of they are able to produce unusual permittivity and permeability which can be used to improve the performance of conventional devices. Metamaterial structures designed to have simultaneously negative permittivity and permeability are known as left-handed materials (LHM). LHM can exude negative refractive indices, generate backward-waves, and even enhance the electromagnetic fields. LHM can be employed to design transformed lenses with better focusing efficiency than conventional one. In this thesis, we make use of the square split-ring resonator and wire as the unit cell to synthesize a number of lenses. Particularly, we synthesize a positive refraction index lens which is conventional lens and a negative refraction index lens and a parabolic refraction lens to achieve focusing effect. CST has been employed to demonstrate the performance of the focusing system. Finally, we analyze the focusing effect of different lens.
39
Chieh-SenLee and 李杰森. "Planar Complementary Split-Ring Resonator for Measuring the Permittivity and Thickness of Multi-Layer Dielectric Materials." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/2ywczv.
Full text
40
You-RenWang and 王友仁. "Design and Implementation of Ultra-Low Frequency Open Complementary Split-Ring Resonator for Whole Blood Coagulation Time Detection." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/whx87v.
Full textAbstract:
碩士國立成功大學
電機工程學系
104
This thesis presents applying microwave sensors based on open complementary split ring resonators (OCSRRs) design to measure the blood coagulation time of the whole blood, which is the first time proof that a microwave wave plane resonance method can be effectively applied to detect the blood coagulation time. The S-parameters were recorded and the frequency deviation was computed using interference-suppression algorithm to detect the slight variation of the permittivity during clotting process. Different from the current well-known methods of blood coagulation time detection, the microwave resonator method has several advantages, including high sensitivity, small amount of samples, easy processing, and non-contact measurement for the whole blood coagulation time detection. There are three major challenges to apply OCSRR microwave sensors for blood coagulation time detection, including the frequency selection, the miniaturization of OCSRR, and highly lossy test sample. We used an impedance analyzer for blood test and analyzed the characteristic frequency of the whole blood. Based on analysis and comparison of the Cole-Cole diagram, the most significant change of the permittivity can be observed near 1 MHz during the coagulation. After analyzing the electric and magnetic field distributions of OCSRR, semi lumped components of capacitors and inductors are used to miniaturize the size of OCSRR to resonate at 1 MHz for the detection of the whole blood property. To solve slight variation of the dielectric constant of the highly lossy material blood, Matlab interference suppression algorithms was applied after a low-noise sampling by the Network Analyzer to filter out the high frequency noise. The captured resonant frequencies were traced in the time domain to observe the change time. Then the prothrombin time (PT) can be measured clearly from the frequency deviation. Finally, the experimental verification including plasma, blood clotting, non-coagulated blood samples was perform, and we can conclude that the aggregation, the shape transformation and the sedimentation of erythrocytes during the coagulation process are the three major factors to result in the permittivity change. Moreover, the resonator methods are compared with the well-established optical methods, both of methods had good accuracy. We had measured data of 20 tubes of whole blood, and the correlation coefficient between PT of resonator methods and PT of manual methods is 0.862. The resonator measuring has the average error of 1.56 sec from the standard manual method.
41
Tzu-Huang, Li, and 黃麗慈. "The Fabrication and Design of the Split ring resonator based on Metamaterials by the Fully Ink-Jet Printing Technology." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/x3j2j2.
Full textAbstract:
碩士國立臺南大學
機電系統工程研究所
102
This study designs and fabricates an split ring resonator with the properties of metamaterials by the fully ink-jet printing technology. The pattern made of nano silver is printed on the flexible polyimide (PI) substrate. S-parameters of this resonator are obtained from the vector network analyzer. The frequency band of the split ring resonator responses in 5.5-6 GHz. It can be converted to obtain the permittivity and magnetic permeability. The fully ink-jet printing technology proposed in this study is robust and cheaper than the MEMS process. Through this fabricated process, the fabrication of metamaterials will become robust and faster. In addition, we expect that this fabricated method can be expanded to the most of manufactured process of film devices, such as SAW devices, transparency film, and metamaterials.
42
Lin, Chih-Yuan, and 林志遠. "Design of Open Loop Multiple Split-Ring Resonator Voltage-Controlled Oscillator and Wide-Operation Range ÷ 3 Injection-Locked Frequency Divider." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/6av8q9.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
102
The important blocks in the phase locked loop (PLL) are the voltage controlled oscillator (VCO) and the divider circuit. The most power consumption of PLL consumes in VCO and divider. The VCO is requested a low phase-noise to avoid corrupting the mixer-converted signal by close interfering tones for VCO circuit, and the Figure of Merit (FOM) of VCO can be determined by it’s performance. Firstly, this thesis designs complementary Colpitts voltage controlled oscillator, A 0.7GHz Colpitts oscillator is designed and implemented in a 0.18μm CMOS 1P6M process. It consists of a Colpitts negative resistance cell and an open square loop resonator. At the supply voltage of 1.8 V, the output phase noise of the oscillator is -86.28 dBc/Hz at 1MHz offset frequency from the carrier frequency of 0.7 GHz(Using in UHF Band). The FOM(figure of merit) is -135.57dBc/Hz. Total oscillator core power consumption is 5.76 mW. Secondly, a new wide locking range divide-by-3 injection-locked frequency divider (ILFD) using a standard 0.18 μm BiCMOS process is presented. The ILFD uses a cross-coupled nMOSFET oscillator with an HBT tail and it also use two HBT injection SiGe HBTs. The injection HBTs serve as harmonic and nonlinear mixers. The core power consumption of the ILFD core is 8.328 mW. The divider’s free-running frequency is tunable from 4.32 to 3.78 GHz by tuning the varactor’s control bias, and at the incident power of 0 dBm. The maximum locking range is 1.87 GHz (23.71%), The incident frequency from 6.95 to 8.82 GHz. The operation range is 2.85 GHz (36.42%), from 6.4 to 9.25 GHz. In addition, the ILFD uses a cross-coupled nMOSFET oscillator with an HBT tail and it also use two HBT injection SiGe HBTs. The effect of hot-carrier stressed injection HBTs on the performance of the ILFD is studied. The stress induces the shift in oscillation frequency, phase noise and HBT output characteristics. It is found the locking range decreases with stress time at fixed dc injection base-emitter bias. Thirdly , a new wide locking range divide-by-3 injection-locked frequency divider (ILFD) using a standard 0.18 μm CMOS process is presented. The ILFD is based on a class-C capacitive cross-coupled oscillator. By changing the dc gate bias of cross-coupled transistors to below the dc drain voltage, the locking range of ILFD has been improved. At the supply voltage of 1.8 V, the core power consumption of the ILFD core is 10.7 mW. The incident power of 0 dBm the divider’s maximum locking range is 3.3 GHz (24.17%),with the incident frequency from 12 to 15.3 GHz. At incident power of 0 dBm the divider’s operation range is 4.8 GHz (35.2%), from the incident frequency 10.5 to 15.3 GHz. Finally ,a wide locking range divide-by-3 injection-locked frequency dividers (ILFDs) using a standard 0.18 μm CMOS process are presented. The ILFDs are based on a cross-coupled n-core MOS LC-tank oscillator with either injection NMOSFETs or pMOSFETs. The core power consumption of the ILFD core with injection nMOSFETs is 10.8 mW at the supply voltage of 0.9V and with circuit core current of 12mA. At the incident power of 0 dBm the maximum locking range is 4.2 GHz (37.17%), from the incident frequency 9.2 to 13.4 GHz. The core power consumption of the ILFD core with injection pMOSFETs is 13.77 mW at the supply voltage of 0.9V and with circuit core current of 15.3mA. At the incident power of 0 dBm the maximum locking range is 2.4 GHz (25%), from the incident frequency 8.4 to 10.8 GHz.
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Dosanjh, Pinder S. "Microwave surface resistance measurements of YBa2Cu3o6+x single crystals and melt textured slabs employing a niobium double split-ring resonator." Thesis, 2001. http://hdl.handle.net/2429/11518.
Full textAbstract:
The microwave surface impedance of YBa2Cu3O6+x was measured using a new niobium
split-ring resonator. For the first time it is shown that this resonator geometry
allows one to measure both small single crystals and large area slabs employing the same
resonator assembly. By careful polishing of the niobium surfaces the niobium split-ring
resonator has achieved a resolution of 0.2µΩ at 2.079GHz, about a factor of 5 better
than its predessesor. Results are presented on both the a and b axis at 2.079GHz and
2.942GHz for a high quality YBa2Cu3O6.5 OrthoII single crystal as well as results on two
YBa2Cu3O6+x top seeded melt textured slabs.
The single crystal results show significant frequency dependence over the narrow
range studied, an indication that the width of the Drude peak is less than what has
been observed in optimally doped YBa2Cu3O6+x. The scattering rates for both the a
and b axis are not well described by a single rate; this is suggestive of two processes
contributing to the scattering. As well, the scattering rate in the b direction seems to be
impurity limited.
Measurements on the two melt textured slabs show that changing the Y2Ba1Cu1O5
concentration from 15-3% has little effect on the surface resistance in the superconducting
state. At 77K, the surface resistance for the best slab is only a factor of 1.3 higher than
that reported for the best Tl2Ba2Ca1Cu2OΔ thin films. [Scientific formulae used in this abstract could not be reproduced.]
44
Ren, Zhao. "Microwave near-field probes to detect electrically small particles." Thesis, 2013. http://hdl.handle.net/10012/8006.
Full textAbstract:
Microwave near-field probes (MNPs) confine evanescent fields to regions that are substantially smaller than the wavelength at the operation frequency. Such probes are able to resolve subwavelength features, thus providing resolution much higher than the classical Abb?? limit. These abilities of MNPs are primarily due to the evanescent nature of the field generated at the tip of the probes. In the past, MNPs with ultra-high resolution were designed by tapering a resonant opening to provide high field concentration and high sensitivity. The limitations of these MNPs were subject to low surface roughness and practical realization challenges due to their geometrical features and vibration control constraints.
Metamaterials with their ability to enhance evanescent fields, lead to the speculation that they could potentially increase the sensitivity of near-field probe. Periodically arranged metamaterial unit elements such as split-ring-resonators (SRRs) can create negative permeability media. Placing such material layer in the proximity of a probe leads to enhancement of the evanescent waves. Guided by this remarkable feature of metamaterials, I proposed an MNP consisting of a wire loop concentric with a single SRR. The evanescent field behavior of the probe is analyzed using Fourier analysis revealing substantial enhancement of the evanescent field consistent with metamaterial theory predictions. The resolution of the probe is studied to especially determine its ability for sub-surface detection of media buried in biological tissues. The underlying physics governing the probe is analyzed. Variations of the probe are developed by placement of lumped impedance loads.
To further increase the field confinement to smaller region, a miniaturized probe design is proposed. This new probe consists of two printed loops whose resonance is tunable by a capacitor loaded in the inner loop. The sensing region is decreased from ??/20 to ??/55, where ?? is the wavelength of the probe???s unloaded frequency.
The magnetic-sensitive nature of the new probe makes it suitable for sensing localized magnetostatic surface resonance (LMSR) occurring in electrically very small particles. Therefore, I proposed a sensing methodology for detecting localized magnetostatic surface (LMS) resonant particles. In this methodology, an LMS resonant sphere is placed concentrically with the loops. A circuit model is developed to predict the performance of the probe in the presence of a magnetic sphere having Lorentz dispersion. Full-wave simulations are carried out to verify the circuit model predictions, and preliminary experimental results are demonstrated. The Lorentzian fit in this work implies that the physical nature of LMSR may originate from spin movement of charged particle whose contribution to effective permeability may be analogous to that of bound electron movement to effective permittivity in electrostatic resonance. Detection of LMSR can have strong impact on marker-based sensing applications in biomedicine and bioengineering.
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Kao, Wei-Chun, and 高維君. "Influence of Materials and Cavities on Optical Force in Dielectric Waveguide and Simulation of Optical Force in Split Optical Ring Resonator." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/39716255755281719330.
Full textAbstract:
碩士國立臺灣大學
應用力學研究所
103
We analyze the optical force in waveguide. Four topics, which are planar waveguides, waveguides with metamaterial, cavities in waveguide and split optical ring resonator will be discussed. We hope the optical force we simulated can be used in practical way. The analytical solution of optical force in plane dielectric waveguide has been derived. First we compare our FEM simulation with analytical solution, and then we modify the materials except waveguide, studying the effect on force. The result shows as the permittivity of gap between waveguides is larger than that of waveguide, the force turns to repulsive. The higher mode of electric field appears as the distance between waveguides and the ratio of permittivity of gap and waveguide increase. We have also derived the analytical solution of the force in waveguide with metamaterial. We find the force becomes discontinuous with the increasing thickness of metamaterial, and the force is a function of the difference between distance and thickness of metamaterial. These phenomenon could be explained due to the dispersion relation of the system. In addition, negative increasing the permittivity of metamaterial makes the curve of force shift. It is known that ellipse cavities in waveguide make the force stronger. We will study the influence of modifying the geometrical parameters and amount of the ellipse cavities on force. Also we will show the relation between force, transmittance and reflectance of electromagnetic wave in the structure. A new structure named “split optical ring resonator,” which has a split on the ring waveguide of the resonator is built. Because the light could be limited in the ring, the field could be also enhanced. As the transmission of resonator is the lowest, the force on split reaches the maximum. The best coupling location, or the maximum force can be found by modifying the distance between the ring and the straight waveguide.
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Gowe, Bruce T. "Studies of the frequency dependence of the microwave surface resistance of high Tc superconducting films using a new superconducting split ring resonator." Thesis, 1997. http://hdl.handle.net/2429/6496.
Full textAbstract:
A new superconducting split-ring resonator has been developed for use in perturbation
measurements of the microwave surface resistance of thin superconducting films. The
experimental setup allowed for the sample temperature to be ramped from 10 - 120 K
during the measurement. The split ring arrangement was such that it could be adjusted
from run to run to operate at a variety of frequencies thus making the apparatus well
suited to exploring the frequency dependence of the film's losses. Results from measurements
on Tl2Ba2CaCu20y films with this resonator at 910 MHz, 1.4 GHz and 2.4 GHz in
conjunction with results from an earlier split-ring resonator at 3.7 GHz [1] suggest that
the losses are not consistent with an UJ2 relationship below 2.4 GHz. Operating at 910
MHz, surface resistances as low as 5/J.Q were easily resolved with perturbations from an
unloaded quality factor of 2xl06 . The 2.4 GHz configuration had a resolution of ILIQ in
surface resistance.
47
Kabiri, Ali. "Artificial Magnetic Materials: Limitations, Synthesis and Possibilities." Thesis, 2010. http://hdl.handle.net/10012/5579.
Full textAbstract:
Artificial magnetic materials (AMMs) are a type of metamaterials which are engineered to exhibit desirable magnetic properties not found in nature. AMMs are realized by embedding electrically small metallic resonators aligned in parallel planes in a host dielectric medium. In the presence of a magnetic field, an electric current is induced on the inclusions leading to the emergence of an enhanced magnetic response inside the medium at the resonance frequency of the inclusions. AMMs with negative permeability are used to develop single negative, or double negative metamaterials. AMMs with enhanced positive permeability are used to provide magneto-dielectric materials at microwave or optical frequencies where the natural magnetic materials fail to work efficiently.
Artificial magnetic materials have proliferating applications in microwave and optical frequency region. Such applications include inversely refracting the light beam, invisibility cloaking, ultra miniaturizing and frequency bandwidth enhancing low profile antennas, planar superlensing, super-sensitive sensing, decoupling proximal high profile antennas, and enhancing solar cells efficiency, among others. AMMs have unique enabling features that allow for these important applications.
Fundamental limitations on the performance of artificial magnetic materials have been derived. The first limitation which depends on the generic model of permeability functions expresses that the frequency dispersion in an AMM is limited by the desired operational bandwidth. The other constraints are derived based on the geometrical limitations of inclusions. These limitations are calculated based on a circuit model. Therefore, a formulation for permeability and magnetic susceptibility of the media based on a circuit model is developed. The formulation is in terms of a geometrical parameter that represents the geometrical characteristics of the inclusions such as area, perimeter and curvature, and a physical parameter that represents the physical, structural and fabrication characteristics of the medium. The effect of the newly introduced parameters on the effective permeability of the medium and the magnetic loss tangent are studied. In addition, the constraints and relations are used to methodically design artificial magnetic material meeting specific operational requirements.
A novel design methodology based on an introduced analytical formulation for artificial magnetic material with desired properties is implemented. The synthesis methodology is performed in an iterative four-step algorithm. In the first step, the feasibility of the design is tested to meet the fundamental constraints. In consecutive steps, the geometrical and physical factors which are attributed to the area and perimeter of the inclusion are synthesized and calculated. An updated range of the inclusion's area and perimeter is obtained through consecutive iterations. Finally, the outcome of the iterative procedure is checked for geometrical realizability. The strategy behind the design methodology is generic and can be applied to any adopted circuit based model for AMMs.
Several generic geometries are introduced to realize any combination of geometrically realizable area and perimeter (s,l) pairs. A realizable geometry is referred to a contour that satisfies Dido's inequality. The generic geometries introduced here can be used to fabricate feasible AMMs. The novel generic geometries not only can be used to enhance magnetic properties, but also they can be configured to provide specific permeability with desired dispersion function over a certain frequency bandwidth with a maximum magnetic loss tangent. The proposed generic geometries are parametric contours with uncorrelated perimeter and area function. Geometries are configured by tuning parameters in order to possess specified perimeter and surface area. The produced contour is considered as the inclusion's shape. The inclusions are accordingly termed Rose curve resonators (RCRs), Corrugated rectangular resonators (CRRs) and Sine oval resonators (SORs). Moreover, the detailed characteristics of the RCR are studied. The RCRs are used as complementary resonators in design of the ground plane in a microstrip stop-band filter, and as the substrate in design of a miniaturized patch antenna. The performance of new designs is compared with the counterpart devices, and the advantages are discussed.
48
(8120606), Zhaoyang Li. "Design and Simulation of Microwave Filters Using Non-uniform Transmission Line and Superformula." Thesis, 2019.
Find full textAbstract:
In this study, a novel and systematic methodology for the design and optimization of
lowpass filters (LPFs), and multiorder-bandpass filters (BPFs) are proposed. The width of the
LPF signal traces consistently follow Fourier truncated series, and the thickness of the substrate
as well. By studying different lengths and other physical constraints, the design meets predefined
electrical requirements. Moreover, superformula is used in split ring resonators (SRRs) designs
to obtain a BPF response and significant structural compactness.
Non-uniform transmission lines, as well as superformula equations, are programmed in
MATLAB, which is also used for analytical validations. Traces are drawn in AutoCAD. The
substrate of LPF is constructed in Pro/e. Finally, the optimized layouts are imported to Ansys
High Frequency Structure Simulation (HFSS) software for simulation and verification. Nonuniform LPFs are optimized over a range of 0-6 GHz with cutoff frequency 3.5 GHz.
Superformula implemented multiorder-BPFs are optimized with cutoff frequency of 1.1 GHz.
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Mädler, Carsten. "Silicon nanowire field-effect transistors for the detection of proteins." Thesis, 2016. https://hdl.handle.net/2144/19408.
Full textAbstract:
In this dissertation I present results on our efforts to increase the sensitivity and selectivity of silicon nanowire ion-sensitive field-effect transistors for the detection of biomarkers, as well as a novel method for wireless power transfer based on metamaterial rectennas for their potential use as implantable sensors. The sensing scheme is based on changes in the conductance of the semiconducting nanowires upon binding of charged entities to the surface, which induces a field-effect. Monitoring the differential conductance thus provides information of the selective binding of biological molecules of interest to previously covalently linked counterparts on the nanowire surface.
In order to improve on the performance of the nanowire sensing, we devised and fabricated a nanowire Wheatstone bridge, which allows canceling out of signal drift due to thermal fluctuations and dynamics of fluid flow. We showed that balancing the bridge significantly improves the signal-to-noise ratio. Further, we demonstrated the sensing of novel melanoma biomarker TROY at clinically relevant concentrations and distinguished it from nonspecific binding by comparing the reaction kinetics. For increased sensitivity, an amplification method was employed using an enzyme which catalyzes a signal-generating reaction by changing the redox potential of a redox pair. In addition, we investigated the electric double layer, which forms around charges in an electrolytic solution. It causes electrostatic screening of the proteins of interest, which puts a fundamental limitation on the biomarker detection in solutions with high salt concentrations, such as blood. We solved the coupled Nernst-Planck and Poisson equations for the electrolyte under influence of an oscillating electric field and discovered oscillations of the counterion concentration at a characteristic frequency.
In addition to exploring different methods for improved sensing capabilities, we studied an innovative method to supply power to implantable biosensors wirelessly, eliminating the need for batteries. A metamaterial split ring resonator is integrated with a rectifying circuit for efficient conversion of microwave radiation to direct electrical power. We studied the near-field behavior of this rectenna with respect to distance, polarization, power, and frequency. Using a 100 mW microwave power source, we demonstrated operating a simple silicon nanowire pH sensor with light indicator.
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Chen, Shih-Chia, and 陳世家. "Wide-band Circuit Extraction of Complementary Split-Ring Resonators." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/10242558882911371668.
Full textAbstract:
碩士大葉大學
電機工程學系
100
In this thesis, we use coupling between a CSRR (Complementary Split-Ring Resonators) structure and a simple signal line to design a one-order low pass filter. First we use a Chebyshev filter form reference, and Resonance theory to find basic equivalent circuit, and extraction elements value. We want to find physical meaning about resonance frequency by simulate the structure. We analyze electric field, electric current and magnetic current to make this theory more consummate. We also propose some modification of equivalent circuit to make simulate result more approaching experiment result.