Дисертації з теми "ZERODHA"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: ZERODHA.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-31 дисертацій для дослідження на тему "ZERODHA".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Masud, Muhammad Mubeen. "Zeroth Order Resonator (ZOR) Based RFID Antenna Design." Diss., North Dakota State University, 2014. https://hdl.handle.net/10365/27485.
Повний текст джерелаАнотація:
Meander-line and multi-layer antennas have been used extensively to design
compact UHF radio frequency identification (RFID) tags; however the overall size
reduction of meander-line antennas is limited by the amount of parasitic inductance
that can be introduced by each meander-line segment, and multi-layer antennas can
be too costly. In this study, a new compact antenna topology for passive UHF RFID
tags based on zeroth order resonant (ZOR) design techniques is presented. The
antenna consists of lossy coplanar conductors and either inter-connected inter-digital
capacitor (IDC) or shunt inductor unit-cells with a ZOR frequency near the operating
frequency of the antenna. Setting the ZOR frequency near the operating frequency is
a key component in the design process because the unit-cells chosen for the design are
inductive at the operating frequency. This makes the unit-cells very useful for antenna
miniaturization. These new designs in this work have several benefits: the coplanar
layout can be printed on a single layer, matching inductive loops that reduce antenna
efficiency are not required and ZOR analysis can be used for the design. Finally, for
validation, prototype antennas are designed, fabricated and tested.
2
Adusumilli, Pallavi. "Effects of Mutual Coupling on Zeroth Order Resonator (ZOR) Antennas." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1459439568.
Повний текст джерела
3
Otoboni, José Antonio. "Estudo da usinabilidade do ZERODUR® no torneamento de ultraprecisão com ferramenta de diamante de ponta única." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/18/18146/tde-31102013-171149/.
Повний текст джерелаАнотація:
Alguns espelhos usados em câmeras de satélite devem apresentar qualidade superficial elevada. Eles são normalmente fabricados em ZERODUR®, um material vitrocerâmico, por meio de processos abrasivos. Observou-se que a qualidade da superfície do material deteriora-se algum tempo após a usinagem, necessitando assim de retrabalho. A causa mais influente desse fenômeno é o crescimento de trincas devido à corrosão sobtensão. Estas trincas são geradas pelas condições impostas nos processos convencionais de lapidação e polimento. Este trabalho apresenta um estudo sobre a usinabilidade do ZERODUR® utilizando torneamento de ultraprecisão com ferramenta de diamante de ponta única como uma alternativa a estes métodos tradicionais. Amostras de ZERODUR® foram submetidas a testes de indentação e riscamento a fim de se estudar as propriedades mecânicas do material, a transição dúctil-frágil e os mecanismos de remoção de material. Com base nesses testes, foi delineado um experimento fatorial do tipo 23 para avaliar a influência das seguintes variáveis de usinagem: profundidade de corte, nos níveis 0,4 e 0,2 \'mü\'m, taxa de avanço, nos níveis 0,3 e 0,1 \'mü\'m/rev e ângulo de saída da ferramenta, nos níveis -5º e -20º. As amostras do experimento foram usinadas em um torno de ultraprecisão com a ferramenta de diamante de ponta única. A qualidade superficial de cada combinação foi avaliada por microscopia eletrônica de varredura e perfilometria óptica interferométrica. Os resultados dos experimentos foram analisados estatisticamente, por meio de análise de variância (ANOVA). Para os intervalos das variáveis testadas verificou-se que o ângulo de inclinação da ferramenta é o que mais afeta a qualidade superficial. Ângulos com inclinações mais negativas (-20º) proporcionaram as melhores qualidades superficiais (em torno de 200 nm). Nos resultados não houve evidência de que o corte do material tenha ocorrido dentro do regime dúctil. Porém, a rugosidade superficial encontrada em algumas combinações de corte sugere que o torneamento de ultraprecisão pode ser uma alternativa ao processo lapidação que antecede o polimento. Este trabalho de caráter exploratório contribui com estimativas de alguns parâmetros ótimos para usinagem do ZERODUR®, fornecendo subsídios para pesquisas futuras sobre este tema.Some mirrors used in satellite cameras must present a high surface quality. They are usually made of ZERODUR®, a brittle glass ceramic, by means of abrasive processes. It was observed that the surface quality of the material deteriorates some time after the machining, thus requiring rework. The most influential cause of this phenomenon is the crack growth due to stress corrosion. These cracks are generated by the conventional machining processes of lapping and polishing. This work presents a study on the machinability of ZERODUR® using ultraprecision turning with single-point diamond tool as an alternative to these traditional methods. ZERODUR® samples were subjected to indentation and nano-scratching tests in order to study the ductile-brittle transition and material removal mechanisms. After that, a \'2 POT.3\' factorial experiment was designed in order to assess the influence of three machining parameters on the resulting surface roughness, which are: depth of cut (tested at levels 0,4 and 0,2 \'mü\'m), feed rate (tested at levels 0,3 and 0,1 \'mü\'m/rev) and rake angle of the cutting tool (tested at levels -5º e -20º). The samples were turned with single-point diamond tool using different combinations of the parameters at the levels described above. The surface quality of each sample was evaluated using an interferometric optical profiler and a scanning electron microscope (SEM). The results of the experiments were statistically evaluated by means of Analysis Of Variance (ANOVA). For the ranges tested, it was found that the rake angle of the tool was the most influential parameter. The angle of -20º provided the best values for surface quality, which were around 200 nm. There was no evidence that the cut of the material occurred in the ductile regime, however, the obtained surface roughness showed that the ultraprecision turning may be a feasible alternative for the lapping process of optical components. This exploratory research contributes to the existing knowledge by providing estimates for optimal parameters of ZERODUR® machining, furnishing empirical basis for future research in this field.
4
Haggans, Charles Wesley. "Polarization properties of zeroth order surface-relief gratings with application to optical storage heads." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/186030.
Повний текст джерелаАнотація:
A rigorous model for treating diffraction from arbitrary profile surface-relief gratings is developed. This model is valid for conical incidence geometries and elliptically polarized incident beams. The model is based on the coupled-wave method of Moharam and Gaylord (J. Opt. Soc. Am. 73, 1105-1112 (1983); J. Opt. Soc. Am. 72, 1385-1392 (1982)). The slow convergence of this model for p polarized incident light is analyzed. The source of this slow convergence is determined to be the use of Fourier series expansions for the permittivity and fields in the grating region. The polarization and energy distribution properties of zeroth order gratings are summarized. Designs are presented for zeroth order gratings that function as retardation and polarization conversion elements for specularly reflected beams. Photoresist gratings are fabricated and characterized by ellipsometric techniques to confirm the predictions of the coupled-wave model and to demonstrate these novel designs. The application of zeroth order gratings to optical storage heads is discussed, and novel head designs based on these components are presented.
5
Zhao, Bo. "Composite Right/Left-Handed (CRLH) Microstrip Resonant Antennas." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1123784412.
Повний текст джерела
6
Henault, Bastien. "Identification des processus physico-chimiques à l’origine des défauts locaux des surfaces polies optique et superpolies." Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC090.
Повний текст джерелаАнотація:
Ce travail de thèse porte sur l’étude des mécanismes physico-chimiques mis en jeu lors du polissage mécano-chimique du Zerodur® (vitrocéramique) par un abrasif à base d’oxydes de cérium. Les défauts obtenus à l’issu du polissage ont été caractérisés en microscopie optique et par microscopie à force atomique (AFM). Il en ressort deux principales populations, à savoir des rayures de type « fines » (longitudinales et continues) causées par des débris de matière polie. La seconde est la typologie « rayure éclat » (fractures perpendiculaires au sens de la rayure) causées par des agglomérats d’abrasif. Des analyses en spectroscopie RX de l’abrasif montrent une augmentation du ratio Ce3+/Ce4+ après la phase de polissage, confirmant la part chimique du polissage du Zerodur®. Des analyses de potentiel zêta ont été menées sur ces mêmes abrasifs et montrent une évolution de la charge de surface des particules abrasives. Des observations AFM montrent que plus la part Ce4+ est importante et meilleure est la qualité finale de la surface polie. La surface polie a également été sondée en ToF-SIMS. Il en ressort la présence d’une couche enrichie en cérium de plusieurs dizaines de nanomètres, lieu de la réaction mécano-chimique de polissage. Plus précisément, cette réaction semble avoir lieu dans la phase vitreuse du Zerodur®This PhD work focuses on the study of the physicochemical mechanisms involved in the chemical-mechanical polishing of Zerodur® (glass-ceramics) with an abrasive based on cerium oxides. The defects observed after polishing were characterized by optical microscopy and atomic force microscopy (AFM). Two main populations were observed, namely "fine" (longitudinal and continuous stripes) caused by debris of polished material. The second is called "scratch" (perpendicular fractures) caused by abrasive agglomerates. RX spectroscopic analyzes of the abrasive showed an increase in the Ce3+/ Ce4+ ratio after the polishing phase. This point confirms the chemical part of Zerodur® polishing. Zeta potential analyzes were carried out on these same abrasives and show an evolution of the abrasive surface charge. AFM observations show that the higher the Ce4+ concentration, the better the final polished surface quality. The polished surface was also probed with ToF-SIMS analyzes. This shows the presence of a cerium-enriched layer of several tens of nanometers, which may be a site for the chemical-mechanical polishing reaction. More precisely, this reaction seems to take place in the glassy phase of Zerodur®
7
Hansen, Glenn Alexander. "TWO ULTRAPRECISE THERMAL EXPANSION INVESTIGATIONS: SODIUM SILICATE - A LOW-EXPANSION CEMENT, AND THERMAL EXPANSION UNIFORMITY OF ZERODUR." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/291814.
Повний текст джерела
8
Shi, Ruirong. "Zeroth-Order Resonator (ZOR) Antenna Using Composite Right/Left-Handed (CRLH ) Microstrip Transmission Line (TL)." University of Cincinnati / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1301714086.
Повний текст джерела
9
Lobos, Fernández Mauricio [Verfasser]. "Homogenization and materials design of mechanical properties of textured materials based on zeroth-, first- and second-order bounds of linear behavior / Mauricio Lobos Fernández." Karlsruhe : KIT Scientific Publishing, 2018. http://www.ksp.kit.edu.
Повний текст джерела
10
Okyay, Ahmet. "Sliding Mode Control Algorithm Development For Anti-lock Brake System." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613568/index.pdf.
Повний текст джерелаАнотація:
In this thesis, a sliding mode controller employing a new sliding surface for
antilock brake system (ABS) is proposed, its stability is proven formally and its
performance is compared with existing sliding mode controllers. The new sliding
mode controller uses the integral-derivative surface, which includes error, its
derivative and its integral, all at the same time. This and the already existing
derivative surface, which includes error and its derivative only, are named zerothorder
sliding surfaces. Their stability analysis is done using first-order auxiliary
surfaces. Auxiliary surfaces equal the sliding surfaces when derivative of the error
becomes zero. The first-order error surface, which includes only the error, and the
integral surface, which includes error and its integral, were also designed for
comparison. During design, tire brake force response is modelled as an
uncertainty. Controllers are simulated on a road with an abrupt change in road
coefficient of adhesion. Controller parameters used are optimized, which results in
comparable stopping distances while braking on a constant coefficient of adhesion
road. Effect of first order actuator dynamics with varying time constants and
actuator absolute time delay were considered. Reaching and sliding properties of
controllers were also investigated, using results on a constant coefficient of
adhesion road. It is observed that zeroth-order sliding surfaces give smoother
response for both derivative and integral-derivative cases. As the controllers
employing error and derivative surfaces get unstable in the presence of actuator
time delay, the integral-derivative surface, proposed in this study, stands as the
best controller.
11
Söderberg, Alexander. "Browsing the Web of Amplitudes." Thesis, Uppsala universitet, Teoretisk fysik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-309989.
Повний текст джерелаАнотація:
We begin by studying field-theory amplitude relations such as the Kleiss-Kuijf, Bern-Carrasco-Johansson, Kawai-Lewellen-Tye and the double copy construction, which are important ingredients in this thesis. Going beyond the field-theory limit we study how the gauge-sector of the heterotic string relates to type I amplitudes through the single valued projection of multiple zeta values. At low energy and for a U(1) gauge group (a single brane) the type I amplitudes are generated by the Born-Infeld action, whereas the corresponding heterotic amplitudes vanish in this limit. As a simple exercise we study Yang-Mills theory deformed by a $F^4$ operator, which is the first correction induced by the Born-Infeld action. This exercise is then generalized by considering the four- and six-point amplitudes in Tseytlin's proposal for a non-Abelian Born-Infeld action. Comparing these amplitudes with those found in type I and heterotic string theory we attempt to gain more insight about the non-Abelian Born-Infeld action.
12
Feng, Le. "An in-depth examination of two-dimensional Laplace inversion and application to three-dimensional holography." University of Dayton / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1406814392.
Повний текст джерела
13
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.
Повний текст джерелаАнотація:
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.
14
Cocheteau, Natacha. "Caractérisation et modélisation d'une adhérence moléculaire renforcée." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4700/document.
Повний текст джерелаАнотація:
Le collage par adhérence moléculaire est un collage basé sur la mise en contact de deux surfaces sans l'utilisation de colle ou matériaux additionnels. Ce procédé de collage est utilisé dans de nombreuses applications, notamment dans les domaines de l'optique terrestre et spatiale. Bien qu'un prototype ait déjà passé avec succès l'environnement spatial - où les contraintes d'utilisations sont différentes de celles rencontrées sur Terre - la spatialisation de cette technologie nécessite une caractérisation plus fine du procédé ainsi qu'une amélioration de la tenue mécanique des interfaces adhérées afin de valider les normes de l'Agence spatiale Européenne. Pour répondre à cette problématique de spatialisation de la technologie, des essais mécaniques ainsi que des analyses chimiques ont été réalisés dans le but d'étudier l'influence de certains paramètres du procédé ) sur la tenue mécanique et l'énergie de collage. Ces essais ont également été réalisés afin de comparer les deux matériaux étudiés : le verre de silice et le Zérodur vis-à-vis de l'adhésion. A l'issue de ces essais, les paramètres à appliquer permettant de doubler la tenue mécanique des interfaces adhérées ont été déterminés. Parallèlement, une loi phénoménologique reliant l'énergie de collage aux précédents paramètres du procédé a été développée ainsi qu'un modèle macroscopique visant à décrire l'intensité d'adhésion. Ces deux modèles une fois couplés permettent de modéliser le comportement normal de l'interface en fonction des paramètres du procédé. Enfin, ces deux lois sont implémentées dans un code éléments finis afin de simuler la propagation de la fissure lors de l'essai de clivage au coinDirect bonding consists in joining two surfaces without the use of any adhesive or additional material. This process is used in several applications, particularly in terrestrial and spatial optics. Although a prototype passed with success spatial environment - where constraints involved are very different from those encountered on Earth - this technology requires a more detailed characterization and an improvement of the mechanical strength of bonded interfaces in order to validate the European Space Agency standards. To address this issue, mechanical tests (double shear tests, cleavage tests and wedge tests) and chemical analysis (wetting tests and XPS spectroscopy) were performed in order to study the influence of some process parameters (roughness, relative air humidity during room temperature bonding, the annealing temperature and time) on the mechanical strength and the bonding energy. These tests compared the two materials used: fused silica glass and Zerodur glass. As a result of these tests, optimal parameters doubling the mechanical strength were also obtained. In the same time, a phenomenological law relating the bonding energy to the previous parameters is developed as well as a macroscopic model to describe the adhesion intensity. Both models when coupled describe the normal behavior of the bonded interface depending on the process parameters. Then, the both laws are implemented in a finite elements model in order to simulate the crack propagation during the wedge test
15
GUPTA, SHUBHAM. "DRAFT IPO PROSPECTUS: ZERODHA." Thesis, 2023. http://dspace.dtu.ac.in:8080/jspui/handle/repository/20471.
Повний текст джерелаАнотація:
This major research project is made out with the learnings and understanding that I made
through the MBA. As, I have done my major in finance, so most of this project is covering the
finance part. In this project, I tried my best to cover all the topics on which a company should
work while bring its IPO. Launching an IPO is a remarkable step in the journey of a company.
When a company going through an IPO, it becomes more recognizable and get better deal from
the potential clients through the press release and financial media coverage. As the companies
have the obligation to publicly disclose information, listed entities are more transparent than
private ones.
One of the unconventional facts about Zerodha that intrigues people is that it managed to join
the "Unicorn" club while being bootstrapped and receiving no outside money from investors.
Based on its $1 billion self-assessed worth, Zerodha joined the club of unicorns. Zerodha has
the highest market share in the broking industry. It has left behind the well-established playersin
this industry. So, with the help of this project, I tried to understand the business model of
Zerodha and its competitors. I also learned about key risks associated with this business. After
that, I will be taking data from the prowessIQ software and will do relative valuation with the
peer. In this , we will also try to reach out the possible price at which they should do book
building exercise. Once the company gets listed, the shareholding pattern of current investors
gets decreased down , so the new shareholding pattern needs to be get calculated.
16
Lu, Yi-Wun, and 陸怡妏. "Subsurface Damage in Precision Grinding of Zerodur." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/79145667979053937846.
Повний текст джерелаАнотація:
碩士國立臺灣大學
機械工程學研究所
100
Zerodur is a glass-ceramic made by Schott AG. With its very low coefficient of expansion, it can be used to produce mirrors which retain acceptable figures in extremely cold environments such as satellite. The primary subject of this study is to reach the characteristics of subsurface damage (SSD) in diamond wheels precision grinding of Zerodur, and establish the model of SSD in Zerodur using different grinding parameters, e.g. depth of cut, speed, feed rate, and different grinding wheel conditions, e.g. grain size and wheel bond. The research results about the grinding parameters show that to reduce the depth of cut or work speed would be effective in reducing SSD, and increase the wheel velocity can reduce SSD. However, above a certain wheel velocity, the SSD increases due to high temperature. The results about the wheel conditions show that the metal bond wheel induces slightly larger SSD than the resin bond wheel. Using wheel with larger abrasive size will cause deeper SSD. The abrasive sizes have a decisive impact on the SSD, which is much larger than the grinding parameters. Experiments on #600 metal wheel with the depth of cut 5μm, work speed of 30mm/min and wheel speed of 10 m/s, the subsurface micro-crack is 2.91μm. If all variables remain the same but with work speed of 10mm/min, it will achieve subsurface micro-crack less than 2.91μm. The results of this study match the theoretical formula, and the empirical formula from curve fitting could predict the subsurface micro-crack depth after grinding within a certain grinding conditions in which the error is less than 24 %.
17
Liou, Dzen-Sor, and 劉增受. "Study of Small holes on Zerodur Triangular Measurement." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/s8hd3z.
Повний текст джерелаАнотація:
碩士國立臺北科技大學
製造科技研究所
102
This study focuses on high aspect-ratio triangular small holes measurement on Zerodur material. In this paper, to measure the geometry of the high-aspct-ratio small holes, a long small spherical stylus tips was designed and attached onto the CMM’s probing head. However, the experimental results show that the undesirable contact will affect the measurement significantly by conventional triggering system of CMM (Renishaw PH-9A). In order to evaluate the quality of the small holes, in this study, the measuring optical scope was used to measure the triangular small holes with horizontal direction due to workpiece transparent property. Using measurement point data, the triangular small holes angle could be calculated easily by mathematic equation. However, the measurement uncertainty and accuracy by optical scope needs to be improved in the future.
18
Hsu, Guo-Mao, and 許國懋. "SIMPLIFIED CPW-FED BROADBAND ANTENNA INVOLVING THE ZEROTH ORDER MODE." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/md7k3n.
Повний текст джерелаАнотація:
碩士大同大學
通訊工程研究所
103
This thesis describes the broadband antenna which is fed with the simplified coplanar waveguide (CPW) in the zeroth order mode, and is based on CRLH-TL (composite right/left handed transmission line ) theory. It is built on the upper surface of an FR4 substrate with thickness of 1.6 mm. A straight shorted strip is connected between the center conductor and the ground plane as a loaded parallel element. To increase the parallel inductance and to save some space, the straight strip can be replaced by a meandered strip. This straight strip will excite the resonance frequency. The measured results show that the fractional bandwidth is extended up to 90% and radiation efficiencies of the ZOR (zeroth-order resonance)，FOR (first-order resonance) and SOR (second-order resonance) are 82.9%，93% and 77.8% respectively. In the 10 dB return-loss bandwidth can cover from 1.8GHz to 4.9GHz and the measured peak gain is between 2.9 and 4.5 dB .
19
Reddy, Aavula Sumanth. "Design of Compact Zeroth-Order Resonant Antenna Based on CRLH TL." Thesis, 2013. http://ethesis.nitrkl.ac.in/4815/1/211EC4153.pdf.
Повний текст джерелаАнотація:
Metamaterial (MTM) Based Antennas are class of antennas inspired by metamaterials to enhance the capability of antenna.One of the new applications is the Zeroth-Order Resonant (ZOR) antenna, which is based on Composite Right Left Handed (CRLH) transmission lines(TLs) periodic structures. In addition, ZOR antenna is easy to fabricate and allows design freedoms. Small physical size, low cost, broad bandwidth & good efficiency are desirable features for an integrated antenna. This thesis presents the design and analysis of Asymmetric compact coplanar waveguide(ACPW)-fed zeroth-order resonant (ZOR) antenna. The antenna designed on a ACPW single layer where vias is used. The ZOR phenomenon is employed to reduce the antenna size. The Composite Right Left Handed (CRLH) unit cell on a single layer simplifies the fabrication process. In addition, the ACPW geometry provides high design freedom, so that bandwidth-extended ZOR antenna can be designed.As an advantage of the proposed method, the size of antenna is reduced, and the resonant frequency of zeroth-order mode is 4.57GHz with radiation efficiency of 75.36 %,simulated -10dB fractional bandwidth up to 9.24% and omni-directional peak gain of 1.93 dBi.
20
Li, Chin-Yuan, and 李金源. "Dual-Band Zeroth-Order Antenna Using Composite Right/Left-Handed Transmission Lines." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/38604475544491480616.
Повний текст джерелаАнотація:
碩士長庚大學
電子工程學研究所
97
In this thesis , arbitrary dual-band antennas are presented by using zeroth , positive and negative order mode oscillating by composite right/left handed transmission lines (CRLH TLs). In the first part of this thesis, we introduce metamaterial and left-hand material . Then we present the concept of CRLH TLs in balanced and unbalanced forms. We also discuss zeroth order mode oscillator in the end of this section. In the second part of this thesis, we use ladders of the capacitors and inductors to approximate the characteristics of CRLH TLs. Then we explain how to design and extract the values of interdigital capacitors and shunt stub inductors used in CRLH TLs. Finally, zeroth order mode oscillators are demonstrated by using zeroth order mode theory. In the third part of this thesis, dual-band antenna is implemented by using CRLH TLs. Thus, the operating frequencies cover all of the mobile communication and WLAN band. Then using concave gap coupled to periodical interdigital capacitors and shunt stub inductors structure to reach the dual-band matching of the zeroth and negative order mode, Finally , a miniaturized antenna is demonstrated by using lumped elements to reach the dual-band results.
21
Chang, Yu-Wei, and 張祐瑋. "A Study of Self-Oscillating Active Integrated Antennas using Zeroth-order Resonator." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/mq78yg.
Повний текст джерелаАнотація:
碩士國立臺灣科技大學
電機工程系
104
A novel metamaterial-based self-oscillating active integrated antenna (AIA) using zeroth-order resonators is developed in this thesis. For the first time, the zeroth-order resonators are connected to a cross-coupled pair to stabilize the oscillation near the zeroth-order resonance of a metamaterial resonator. Two designs are developed in this thesis. First of all, a novel self-oscillating AIA based on zeroth-order resonators is proposed. The connecting line between the gate and the other drain terminals in a cross-coupled pair is broken up to insert a zeroth-order resonator in between. By utilizing the zero-phase-shift property of a zeroth-order resonator, the phase of the feedback loop is zero and the oscillation starts. The oscillation parameters are investigated in details. A DC converter is also integrated with the AIA to serve as the dc bias network. It hence gets rid of the bulky power supply used in laboratory demonstration. Secondly, to achieve frequency reconfigurable self-oscillating AIA, the circuit layout of the previous case is re-investigated to develop another zeroth-order resonator. Different from the former design, in the latter case, by disconnecting the shunt inductance, the metamaterial resonator also facilitates +1 mode operation as a negative μ resonator (MNG). It hence generates another oscillation at a higher frequency. The two oscillation modes are separately investigated by experiments in this thesis, and the full integration will be a topic for future study
22
Balu, Narayana Srinivasan. "Propagation Prediction Over Random Rough Surface By Zeroth Order Induced Current Density." 2014. https://scholarworks.umass.edu/masters_theses_2/129.
Повний текст джерелаАнотація:
Electromagnetic wave propagation over random sea surfaces is a classical problem of interest for the Navy, and significant research has been done over the years. Here we make use of numerical and analytical methods to predict the propagation of microwaves over random rough surface. The numerical approach involves utilization of the direct solution (using Volterra integral equation of the second kind) to currents induced on a rough surface due to forward propagating waves to compute the scattered field. The mean scattered field is computed using the Monte-Carlo method. Since the exact solution (consisting of an infinite series) to induced current density is computationally intensive, there exists a need to predict the propagation using the closely accurate zeroth order induced current (first term of the series) for time-varying multiple realizations of a random rough surface in a computationally efficient manner. The wind-speed dependent, fully-developed, Piersen-Moskowitz sea spectrum has been considered in order to model a rough sea surface, although other partially-developed roughness spectra may also be utilized. An analytical solution based on the zeroth order current density obtained by deriving the mean scattered field as a function of the range and vertical height by directly using the Parabolic Equation (PE) approximation method and the resulting Green's function has been utilized for a comparative study. The analytical solution takes into account the diffused component of the scattered field.
23
Chiu, Edward D., and 邱冠諺. "Dual-Band Dual-Zeroth Order Resonant Antenna using Open and Short Terminations." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/78556436568929125874.
Повний текст джерелаАнотація:
碩士國立交通大學
電機學院電信學程
102
In this thesis, a dual band antenna design using dual zero-order resonance is proposed. General zeroth order resonant antenna (ZOA) using a zero-order and negative-order resonance to achieve dual band. It needs two units cell in cascade. The proposed ZOA reduces the cell number to one, which leads to the shrink of the antenna size. The design begins with the synthesization of the zero-order resonance unit cell, which is composed of an interdigital capacitor and short stub. Then, a well-designed termination circuits is proposed to enable simultaneous excitation of the zeroth-order series and shunt resonances. In order to validate the above concepts, a dual band ZOA is proposed. The antenna is designed that the zeroth-order series and shunt resonance are located at 1.8 GHz and 2.4 GHz. The termination circuit is realized by an inductor series with a parallel LC tank that its impedance is open at 1.8 GHz and short at 2.4 GHz. When the termination circuit is used, the antenna can resonate at the designed 1.8 GHz and 2.4 GHz. Finally, a dual band matching circuit is proposed to match the antenna to a 50Ω terminal. This antenna avoids the use of lumped element and multiple unit cells, which leads to further cost reduction of the ZOA.
24
Shih, Yi-Sen, and 施亦陞. "Miniaturized and Bandwidth-Enhanced Zeroth-Order Resonant Antenna Based on Short-Ended Structure." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/z83ja5.
Повний текст джерелаАнотація:
碩士國立交通大學
電信工程研究所
102
In this thesis, two types of improvement on Composite Right/Left Handed transmission line short-ended zeroth-order resonant antenna are presented. First unit cell of antenna combines high impedance transmission with interdigital structure so as to reduce the antenna area. The second antenna using short-ended theory and lumped elements relation with Q factor to design the Q factor of unit cell lower so as to increase the antenna bandwidth. The first and two chapters introduce the applications, operation principle and theory of CRLH-TLs and ZOR. In the third chapter, miniaturized CRLH-TLs short-ended ZOR antenna is presented. The unit cell of antenna combines high impedance transmission with interdigital structure, the unit cell has higher series capacitor and inductor and lower resonant frequency so as to reduce the antenna area. After fabricating this circuit on Rogers 5880 of 62mils, bandwidth of return loss and radiation pattern peak gain are measured 3.6% and 1.24 dBi which have good agreement. In the fourth chapter, short-ended bandwidth-enhanced ZOR antenna is presented. Using higher series capacitor and lower series inductor to decrease the Q factor so as to increasing the bandwidth. Meanwhile, research the relation between the length and number of interdigital capacitor and bandwidth of antenna to design the antenna in the best performance way. After fabricating this circuit on Rogers 5880 of 62mils, bandwidth of return loss and radiation pattern peak gain are measured 15.1% and 1.62 dBi.
25
Fu, Chun-Lin, and 傅俊霖. "Optimization of Heat Transfer Performance of the Zeroth-Level-Bifurcation Tree-Shaped Fins." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/35538979486726087802.
Повний текст джерелаАнотація:
碩士大同大學
機械工程學系(所)
99
In this thesis, we investigate heat transfer performance of zeroth-level-bifurcation tree-shaped fins under the constraint of a fixed heat flux and the total volume of fins. We studied the effects of the number of fins (N), the orientation of fins, the width ratio between thin fins and the thick fin (D2/D1), the height of the thick fin (h/H), and Reynolds number (Re) on the thermal performance of tree fins. We find that increasing Reynolds number can enhance the heat transfer performance, but the improvement slows down as Reynolds number increases. Increasing the fin-width ratio can increase the heat transfer area, but an improved heat removal rate does not observed as undersigned architecture will weaken the flow efficiency. It is shown that the best performance is discovered when the fin-width ratio is between 0.4 and 0.8. An optimized thick fin height varies case by case, and it ranges from 0.2 to 0.6. The optimized orientation of the tree fins is greatly influenced by the number of fins. Among all types discussed in this thesis, the best design is Type_h, which includes eight fins and its orientation is to face the flow directly.
26
Deng, En, and 鄧恩. "Novel Dual-Band Open-Ended Zeroth-Order Resonant Antenna and Switchable Multi-polarization Slot Antenna." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/31160573603268034901.
Повний текст джерелаАнотація:
碩士國立交通大學
電信工程研究所
105
In this thesis, two types of antenna are presented. Among these two types of antenna, one of them is the dual-band zeroth-order antenna. The second one is multi-polarization antenna. The first two chapters introduce the basic theory. In the third chapter, it is a dual-band zeroth-order antenna, by using the theory of composite right/left handed to be zeroth-order, and different from the regular circuit to dual-band. Using CPW to increase its bandwidth. After fabricating this antenna on Ro 5880 62mil, it shows that the theory is workable. In the fourth chapter, a multi-polarization antenna is synthesized by using microstrip line to make an equal power network and feed in a CPW slot antenna. Combining two different mode, we can get a circular polarization. With adding switches, we can get four polarizations -two linear polarizations and two circular polarizations.
27
Chen, Po-Wei, and 陳柏偉. "Asymmetric Coplanar Waveguide (ACPW) Zeroth-Order Resonant (ZOR) Antenna with High Efficiency and Bandwidth Enhancement." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/77798305499089596607.
Повний текст джерелаАнотація:
碩士國立交通大學
電信工程研究所
100
In this paper, we propose the new type of zeroth-ordered antenna (ZOR antenna) based on composite right/left-handed transmission line (CRLH-TL). The feature of ZOR based on periodic structure is employed to reduce the antenna size. Therefore, the researches of ZOR antenna have gathered great importance in recent years. However, these antennas are suffered from narrow bandwidth generally such that it is hard to apply to wireless communication systems. This new type of CRLH-TL is based on asymmetric coplanar-waveguide (ACPW). ACPW is proposed to realize a bandwidth-extended antenna. The ACPW structure not only provides the design freedom but also overcome the design constraint of the traditional CPW. The ACPW ZOR antenna is verified by both full-wave simulations and experiments. As an advantage of the proposed method, the size of antenna is reduced and has good radiation efficiency, extended fractional bandwidth and good peak gain with omni-direction.
28
Yang, Shu-Yen, and 楊樞彥. "Bandwidth and Efficiency Enhancement of Miniaturized Antennas by Merging Dual-Resonances and Bisecting Zeroth Order Resonator Antennas." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/61298356238360159780.
Повний текст джерелаАнотація:
碩士國立交通大學
電信工程研究所
100
In this thesis, we work on finding methods to improve the disadvantages of electrically small antenna (ESA) such as narrow bandwidth and low efficiency at the same time. The research is divided into two parts. The first branch investigates merging two resonances which have higher and lower efficiency, respectively. After merging the two resonances, the efficiency and bandwidth of the one with lower efficiency increased, and the bandwidth of higher one also extended while efficiency is almost fixed. To practice this mechanism, a small planar microstrip antenna which is composed of a split ring resonator (SRR) [higher efficiency] and a shorted spiral [lower efficiency] etched on a upper dielectric slab. The pin drills through a bottom dielectric layer on which a feed line comprising a rectangular microstrip and a meander line for matching is printed. The increase of in bandwidth and efficiency is by more than triple that of the single band counterpart. Compared to conventional patch antennas, the size reduction is by 87%. The second part of the work focuses on improving the performances of zeroth order resonance (ZOR) antennas. The ZOR has infinite wavelength characteristic which causes ZOR can be used for antenna miniaturization. However, the narrow bandwidth and low efficiency limit its applications. By bisecting symmetric ZOR antenna, the antenna dimension and quality factor (Q) are decreased remarkably. We prove it by calculating Q which is extracted from the parameters of equivalent circuit model. Therefore, the bandwidth and efficiency are increased. A bisected ZOR antenna based on bisected inter-digital capacitor-loaded transmission line (B-CL-TL), with extended bandwidth and higher radiation efficiency is proposed. The antenna consists of two cascaded bisected co-planar inter-digital capacitors as series capacitors shorted to the ground plane at one end. A meander-line inductor is implemented for matching. Compared to the CL-TL ZOR antenna, the ratio of increase of bandwidth and efficiency is 2.7 and 1.5, respectively. In this thesis, we prove from theorem and experiment that bisecting symmetric ZOR antenna not only reduce antenna size, but also increase efficiency and bandwidth.
29
Brichard, Joelle. "On Using Graphical Calculi: Centers, Zeroth Hochschild Homology and Possible Compositions of Induction and Restriction Functors in Various Diagrammatical Algebras." Thesis, 2011. https://doi.org/10.7916/D87H1RKG.
Повний текст джерелаАнотація:
This thesis is divided into three chapters, each using certain graphical calculus in a slightly different way. In the first chapter, we compute the dimension of the center of the 0-Hecke algebra Hn and of the Nilcoxeter algebra NCn using a calculus of diagrams on the Moebius band. In the case of the Nilcoxeter algebra, this calculus is shown to produce a basis for Z(NCn) and the table of multiplication in this basis is shown to be trivial. We conjecture that a basis for Z(Hn) can also be obtained in a specic way from this topological calculus. In the second chapter, we also use a calculus of diagrams on the annulus and the Moebius band to determine the zeroth Hochschild Homology of Kuperberg's webs for rank two Lie algebras. We use results from Sikora and Westbury to prove the linear independence of these webs on these surfaces. In the third chapter, we use other diagrams to attempt to find explicitely the possible compositions of the induction and restriction functors in the cyclotomic quotients of the NilHecke algebra. We use a computer program to obtain partial results.
30
Yang, Kai-Chieh, and 楊凱傑. "Development of an intelligent horizontal micro machine tool with high-frequency vibration assisted machining and research of nano milling-grinding on Zerodur® glass ceramic." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/4tzbnz.
Повний текст джерела
31
Liu, Chun-Chih, and 劉峻志. "Application of Composite Right/Left-Handed (CRLH) Transmission Line for the Dual-arm-spiral Zeroth-order Resonant Antenna and Coupled-line-directional-coupler Diplexer." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/12999661866422527953.
Повний текст джерелаАнотація:
碩士國立交通大學
電信工程研究所
101
This thesis dedicates to the applications of composite right/left-handed (CRLH) transmission line, and it consists of two parts. A miniaturized and zeroth-order-resonant (ZOR) antenna based on dual-arm spiral structure is presented in the first part. The second part introduces a novel bandwidth-engineered diplexer realized by a symmetric CRLH coupled-line directional coupler with complete forward and backward couplings. Widespread use of the wireless communications in our daily life demands the development of compact and portable electronic products. As an essential element in the communication systems, small antennas are required to fit the limited space available. Unlike the conventional resonant antenna needs at least half-wave resonant length, the ZOR antenna created by the CRLH transmission line has zero phase constant and is independent of the resonant length. Therefore, ZOR antennas provide a good alternative to miniaturize antenna size without considering the resonant lengths. In addition, the ZOR antenna supports infinite guided wavelength, this substantially increases the effective area of antenna and thus improves the radiation efficiency. This thesis presents a compact ZOR antenna by using two spiral arms with a shorted via. The proposed dual-arm spiral unit cell is able to implement and tailor the CRLH lumped elements easily in a compact fashion. Particularly, the gap coupling between the spiral arms contributes to the series capacitance C_L and the metallic via at the end of one arm results in the shunt inductance L_L. The resonant frequency and thus the miniaturization factor can be engineered easily by adjusting the spiral parameters that determine the corresponding circuit elements. These arms not only realize the most essential components of CRLH transmission line mentioned above, but also effectively increase the edge coupling and shrink the antenna size, occupying the smallest footprint among the ZOR antennas in terms of electrical wavelength. Moreover, this compact antenna exhibits dipole-like radiation patterns with a peak gain of -0.53 dBi and a radiation efficiency of 53%, and meeting the omi-directional requirement of antenna in the portable device. The second part proposes a novel bandwidth engineering diplexer realized by the symmetric CRLH coupled-line directional coupler with complete forward and backward couplings. The operating principle is investigated by the even/odd mode analysis, and it deduces that only a set of dispersion diagrams and Bloch impedances rendering the best isolation in the forward region. In addition, the bandwidth engineering is demonstrated by controlling the distance between the vias. The 7-unit-cell case is implemented under the consideration of the isolation, bandwidth, coupling length and the cavity modes of metal housing. The measured 3-dB bandwidth of forward and backward coupling bands are in the range from 4.19 GHz to 4.9 GHz and 5.6 GHz to 6.23 GHz with the maximum insertion loss of -1.3 dB and -0.9 dB, the corresponding fractional bandwidths are respectively 15.6% and 10.7%.