Дисертації з теми "Scattering matrix method"
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Wang, Peng. "IMPEDANCE-TO-SCATTERING MATRIX METHOD FOR LARGE SILENCER ANALYSIS." UKnowledge, 2017. https://uknowledge.uky.edu/me_etds/102.
Повний текст джерелаHarvey, A. "Electron re-scattering from aligned molecules using the R-matrix method." Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1302063/.
Повний текст джерелаWeiss, Thomas. "Advanced numerical and semi-analytical scattering matrix calculations for modern nano-optics." Thesis, Clermont-Ferrand 2, 2011. http://www.theses.fr/2011CLF22150.
Повний текст джерелаThe optical properties of nanostructures such as photonic crystals and metamaterials have drawn a lot of attention in recent years [1–9]. The numerical derivation of these properties, however, turned out to be quite complicated, especially in the case of metallo-dielectric structures with plasmonic resonances. Hence, advanced numerical methods as well as semi-analytical models are required. In this work, we will show that the scattering matrix formalism can provide both. The scattering matrix approach is a very general concept in physics. In the case of periodic grating structures, the scattering matrix can be derived by the Fourier modal method [10]. For an accurate description of non-trivial planar geometries, we have extended the Fourier modal method by the concept of matched coordinates [11], in which we introduce a new coordinate system that contains the material interfaces as surfaces of constant coordinates. In combination with adaptive spatial resolution [12,13], we can achieve a tremendously improved convergence behavior which allows us to calculate complex metallic shapes efficiently. Using the scattering matrix, it is not only possible to obtain the optical properties for far field incidence, such as transmission, reflection, absorption, and near field distributions, but also to solve the emission from objects inside a structure and to calculate the optical resonances of a system. In this work, we provide an efficient method for the ab initio derivation of three-dimensional optical resonances from the scattering matrix [14]. Knowing the resonances in a single system, it is in addition possible to obtain approximated resonance positions for stacked systems using our method of the resonant mode coupling [15, 16]. The method allows describing both near field and far field regime for stacked two-layer systems, including the strong coupling to Fabry-Perot resonances. Thus, we can study the mutual coupling in such systems efficiently. The work will provide the reader with a basic understanding of the scattering matrix formalism and the Fourier modal method. Furthermore, we will describe in detail our extensions to these methods and show their validity for several examples
Suryadharma, Radius Nagassa Setyo [Verfasser], and C. [Akademischer Betreuer] Rockstuhl. "T-matrix method for the analysis of electromagnetic scattering / Radius Nagassa Setyo Suryadharma ; Betreuer: C. Rockstuhl." Karlsruhe : KIT-Bibliothek, 2020. http://d-nb.info/1212512499/34.
Повний текст джерелаZhai, Pengwang. "A fourth-order symplectic finite-difference time-domain (FDTD) method for light scattering and a 3D Monte Carlo code for radiative transfer in scattering systems." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1839.
Повний текст джерелаAlexander, Jennifer Mary. "Optical properties of mineral dust aerosol including analysis of particle size, composition, and shape effects, and the impact of physical and chemical processing." Diss., University of Iowa, 2015. https://ir.uiowa.edu/etd/1819.
Повний текст джерелаTricoli, Ugo [Verfasser], and Klaus [Akademischer Betreuer] Pfeilsticker. "Electromagnetic scattering with the GDT-matrix method: an application to irregular ice particles in cirrus / Ugo Tricoli ; Betreuer: Klaus Pfeilsticker." Heidelberg : Universitätsbibliothek Heidelberg, 2015. http://d-nb.info/1180501780/34.
Повний текст джерелаAzizoglu, Suha Alp. "Time Domain Scattering From Single And Multiple Objects." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609413/index.pdf.
Повний текст джерелаLi, Ming. "The study of electromagnetic wave propagation in photonic crystals via planewave based transfer (scattering) matrix method with active gain material applications." [Ames, Iowa : Iowa State University], 2007.
Знайти повний текст джерелаChobeau, Pierre. "Modeling of sound propagation in forests using the transmission line matrix method : study of multiple scattering and ground effects related to forests." Thesis, Le Mans, 2014. http://www.theses.fr/2014LEMA1016/document.
Повний текст джерелаThe prediction of sound propagation in presence of forest remains a major challenge for the outdoor sound propagation community. Reference numerical models such as the Transmission Line Matrix (TLM) method can be developed in order to accurately predict each acoustical phenomenon that takes place inside forest. The first need for the TLM method is an efficient theory-based absorbing layer formulation that enables the truncation of the numerical domain. The two proposed absorbing layer formulations are based on the approximation of the perfectly matched layer theory. The most efficient proposed formulation is shown to be equivalent to wave propagation in a lossy media, which, in the TLM method formulation, is introduced using an additional dissipation term. Then, the ability of the TLM method for the simulation of scattering is studied comparing the numerical results to both analytical solutions and measurements on scale models. Lastly, the attenuation of acoustic levels by a simplified forest is numerically studied using several arrangements of cylinders placed normal to either reflecting or absorbing ground. It is observed that randomly spaced arrangements are more inclined to attenuate acoustic waves than periodic arrangements. Moreover, the sensitivity to the density, the length of the array and the ground absorption is tested. The main trend shows that the density and the distribution are two important parameters for the attenuation. In future work, it can be interesting to look at the sensitivity of each parameter. This study could then be used to relate the morphology (i.e. distribution, density, length) of a forest to the acoustical properties of the forest
Rezaiesarlak, Reza. "Design and Detection Process in Chipless RFID Systems Based on a Space-Time-Frequency Technique." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/73506.
Повний текст джерелаPh. D.
Cotter, Nicholas Paul Kyle. "Scattering matrix modelling of optical gratings." Thesis, University of Exeter, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300552.
Повний текст джерелаFabregas, Flavia Francesc. "A numerical tool for the frequency domain simulation of large clusters of wave energy converters." Thesis, Ecole centrale de Nantes, 2017. http://www.theses.fr/2017ECDN0011.
Повний текст джерелаCompact arrays of small wave absorbers constitute an example of the multiple existing categories of wave energy converters (WECs) and have been identified as being an advantageous solution for the extraction of wave energy when compared to a big isolated point absorber. Among the numerous challenges associated with the numerical modeling of such devices, one of the most relevant one is the evaluation of the hydrodynamic interactions amid the large number of floats O(100) they are composed of. Direct computations with standard Boundary Element Method (BEM) solvers, used extensively in wave/structure interaction problems, become prohibitive when the number of bodies increases. Thus, there is a need to employ an alternative approach more suitable for the study of the multiple-scattering in large arrays. In this work, the Direct Matrix Method interaction theory has been implemented. Based on characterizing the way a WEC scatters and radiates waves, this methodology enables one to significantly reduce the number of unknowns of the classical boundary value problem dealt with by standard BEM solvers and, therefore, the computational time. The acceleration provided by the numerical tool developed has allowed examining the power capture of a generic bottom-reference heave-buoy array WEC and optimizing its layout. We have shown that there exist an optimum number of floats for a given device footprint. Exceeding this number results in a “saturation” of the power increase which is undesirable for the economic viability of the device
Barlabé, i. Dalmau Antoni. "Anàlisi de discontinuïtats finline." Doctoral thesis, Universitat Politècnica de Catalunya, 1996. http://hdl.handle.net/10803/6936.
Повний текст джерела-el método de las líneas con discretizacion uniforme y no uniforme.
-el método de los elementos finitos aplicado al análisis de guías homogéneas e inhomogeneas.
-el método de la matriz de lineas de transmisión tridimensional.
-el método de la matriz se generalizada para el análisis de estructuras uniformes y discontinuidades planares.
-el método del dominio espectral para el análisis de estructuras planares uniformes.
-el método del circuito planar con corrección de la dispersión.
Se ha elegido el método de la resonancia transversal generalizado como el mas idóneo para el análisis preciso y rápido de discontinuidades finline con un mínimo de recursos informáticos. Se ha desarrollado incluyendo el carácter singular de los campos en las aristas de la estructura, consiguiéndose minimizar el fenómeno de la convergencia relativa y obteniéndose resultados precisos con expansiones reducidas de las funciones modales que representan los campos, validándose los resultados obtenidos al analizar diversas estructuras con medidas experimentales.
Liu, Hainan. "Theoretical study of electron collisions with NO2 and N2O molecules for control and reduction of atmospheric pollution." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPAST030.
Повний текст джерелаThis thesis presents theoretical investigations on electron scattering with two polyatomic molecules of atmospheric pollution interest, the NO2 and N2O molecules. Regarding the NO2 molecule, we study the vibrational excitation between the lowest levels within the ground electronic states of this molecule. The calculation is carried out by an approach that combines the normal modes approximation for the vibrational states of the NO2, the UK R-matrix code to obtain electron–molecule S-matrix for fixed geometries of the target and the vibrational frame transformation to evaluate the scattering matrices for vibrational transitions. To our knowledge, the vibrational excitation cross section calculated in this thesis is reported for the first time for NO2 molecule. The uncertainty estimation of the results is thus performed to validate the present theoretical approach. Similarly, the vibrational excitation cross sections of N2O molecule are determined. The obtained results are in reasonable agreement with experimental data. The rate coefficient of vibrational excitation are obtained from the cross-sections for temperatures in the 10–10000 K range. The rotational structure of the target neutral molecules is neglected in the present approach, which implies that the obtained cross-sections and rate coefficients should be viewed as averaged over initial rotational states and summed over final rotational states of the corresponding initial and final vibrational levels. Finally, the dissociative electron attachment (DEA) of NO2 are also studied in this thesis. This process competes with vibrational excitation at the scattering energy range below the first electronic excited state of the target. The DEA cross section is calculated by the method based on the Bardsley-O’Malley theory developed for diatomic molecules and generalized to complex polyatomic molecules by Chi Hong Yuen et al. afterwards compared with available experimental measurements. The obtained results could be used in plasma modeling for control and reduction of atmospheric pollution
Jiang, Xianwu. "Hydrocarbon molecules databases for waste treatment applications." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPAST039.
Повний текст джерелаIn this thesis, we investigate the vibronic (de-) excitation and dissociative recombination of CH+ by low-energy electron impact. We first develop a theoretical approach for the electron-impact vibronic (de-) excitation of CH+. In this approach, the fixed-nuclear R-matrix method is employed to compute electron-ion scattering matrices in the Born-Oppenheimer approximation. A vibronic frame transformation and the closedchannel elimination procedure in a spirit of molecular quantum defect theory are employed to construct an energy-dependent scattering matrix describing interactions between vibronic channels of the target ion induced by the incident electron. The obtained scattering matrix accounts for Rydberg series of vibronic resonances in the collisional spectrum. Cross sections for vibronic excitation for different combinations of initial and final vibronic states are computed. A good agreement between electronic-excitation cross sections, obtained using the quantum defect theory and in a direct R-matrix calculation, demonstrates that the present approach provides a reliable tool for determination of vibronic (de-) excitation cross sections for targets with low-energy electronic resonances. Such targets were difficult to treat theoretically using earlier methods. Within the same framework applied for the vibronic (de-) excitations, we further compute the cross section for low-energy dissociative recombination of CH+ coupling the outgoing-wave basis function defined by complex absorbing potential. The contribution of the three lowest X 1Σ +, a 3Π and A 1Π ionic states and the Rydberg series converging to those states are taken into account. The obtained DR cross sections are quantitatively in good agreement with the experimental measurements and exhibit a resonanc feature analogous to the experimental cross-section curve. The origination of the prominant resonances in the computed results are analyzed through computing the DR probabilities for the partial waves of the incident electron. The d-type partial waves including dσ, dπ and dδ are found considerably contributing to the DR of the ground-state CH+. This may explain the discrepancies observed between thoery and experiment in the preceeding studies
Chiniard, Renaud. "Contribution à la modélisation de la surface équivalente radar des grandes antennes réseaux par une approche multi domaine/Floquet." Toulouse 3, 2007. http://www.theses.fr/2007TOU30295.
Повний текст джерелаThis study proposes to treat large array antennas with an original approach. It makes it possible to reach problems whose great dimensions lead traditional and rigorous methods to be unsuccessful. The first part is devoted to the description of the employed methods. The first one is the multi domain method which makes it possible to split in sub domains the initial problem. Each domain is then calculated using the numerical method (integral equations, finite elements,…) adapted. It allows to obtain a condensed operator (S matrix) for each sub domain in an uncoupled way. Once they have been put together with the feeding, the problem can be solved. The main advantage lies in the modular approach which makes it very efficient in parametric studies by re-use of the matrices S of unchanged volumes. We further present the development in Floquet modes, assuming the planar, infinite and periodic hypothesis. It thus makes it possible to reduce the problem to the size of the elementary cell. In the second part, the hybridization of the two methods previously introduced is shown. It is discussed on a rectangular guide array case which, in addition to validating our approach, allows the installation of physical indicators. To enhance our tool, in the next chapter we couple the array to its mechanical support and propose an efficient modelling of this global realistic antenna. The final chapter makes it possible to confront our code with the measurements of one real array antenna. It allows to estimate all the capabilities of the method developed during this study. At the end of this study, a software tool has been developed and it makes it possible to calculate Radar Cross Section of the large antenna arrays inserted in their supports and for various conditions of feeding impedances
Ghazel, Ramzi. "Méthodes de caractérisation en bruit des dispositifs radiofréquences multi accès." Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0122.
Повний текст джерелаIn any microwave telecommunication system, noise performance is a very important criterion for receiving chain devices. Knowledge of the internal noise sources of the components and their correlation makes it possible to predict and optimize the noise performance of a receiver. This theme is the subject of numerous studies and publications around the world. The work proposed in this thesis consists in evaluating the noise performance of a multiport device (N-ports) in the most general sense and without any approximation, based on a new method of extracting the entire noise wave correlation matrix that contains all the information relating to noise performance. This new method is based on the use of noise wave formalism and the scattering matrix[S], the extraction results are validated by calculations and measurements on a two-port device (passive and active) and on a 4-port in standard and mixed mode (passive and active)
Onelli, Olimpia Domitilla. "Complex photonic structures in nature : from order to disorder." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/273768.
Повний текст джерелаHunter, Brandon. "Channel Probing for an Indoor Wireless Communications Channel." BYU ScholarsArchive, 2003. https://scholarsarchive.byu.edu/etd/64.
Повний текст джерелаSilva, Marcello Antônio Ferreira Marques da. "Caracterização óptica e estrutural de materiais isolantes dopados com metais de transição do grupo do ferro." Universidade do Estado do Rio de Janeiro, 2010. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=6727.
Повний текст джерелаThe aim of this work was the investigation of optical and structural properties of insulating materials containing iron group metal transition ions as substitutional impurities. The used techniques for the study of MgGa2O4, MgGa2O4 + B-Ga2O3 and ZnGa2O4 samples doped with Cr3+ and Fe3+ were: photoluminescence, excitation, X-ray diffraction, neutron scattering, Rietveld method for structure refinement and photoacoustic spectroscopy. These techniques allow the determination of impurity site coordination, the assignment of energy transitions, the calculation of energy parameters and the determination of crystallographic properties. The samples present broad energy bands at visible and infrared spectral regions. These transitions point to the relevance of this study for being of technological interest. In the first chapter we present an introduction to crystal field theory. In the second chapter we present the photoluminescence and excitation measurements of MgGa2O4 doped with 0.1, 0.5, 1.0 and 5.0 % of Cr3+ at 77 K and room temperature. In the third chapter we used the photoluminescence, excitation, neutrons scattering, X-ray diffraction, photoacoustic and Rietveld method for analysis of the MgGa2O4, MgGa2O4 + B-Ga2O3 system containing 0.1, 0.5, 1.0 and 5.0 % of Cr3+. In the fourth chapter we show the photoacoustic results for ZnGa2O4 doped with 5% and 10% of Fe3+.
Moeferdt, Matthias. "Nonlocal and Nonlinear Properties of Plasmonic Nanostructures Within the Hydrodynamic Drude Model." Doctoral thesis, Humboldt-Universität zu Berlin, 2017. http://dx.doi.org/10.18452/18129.
Повний текст джерелаThis thesis deals with the nonlocal and nonlinear properties of plasmonic nanoparticles, as described by the hydrodynamic model. The hydrodynamic material model represents an extension of the Drude model that contains corrections to the descriptions of the electron plasma. After a thorough derivation of the material model, analytical discussions of nonlocality are presented for the example of a single cylinder. The frequency shifts in the scattering and absorption spectra are quantified and treated asymptotically. Furthermore, by applying a conformal map, the problem of a cylindrical dimer is solved in the electrostatic limit and the modes of the structure are determined. These investigations lay the foundations for numerical investigations which are performed employing the discontinuous Galerkin time domain method. The analytical knowledge of the modes, in conjunction with group theoretical considerations and numerical analysis, enables the formulation of rigorous selection rules for the excitation of modes by linear and nonlinear processes. In further numerical studies, the influence of nonlocality on the field enhancement in dimer structures and double-resonant behavior (a resonance is found at the frequency of the incoming light and at the second harmonic) are investigated.
Cassiani-Ingoni, Lionel. "Etude d'un hydrogel, copolymere (mma-co-vp) utilise comme precurseur de lentilles de contact : caracterisation du gel, diffusion et activite du lysozyme dans la matrice." Paris 6, 1987. http://www.theses.fr/1987PA066299.
Повний текст джерелаLian, Chii-Fa, and 連啟發. "A scattering-matrix method to study the conductance propoties of GaAs narrow wire." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/12569495837144781236.
Повний текст джерела國立清華大學
電子工程研究所
92
We study two types of different scattering-matrix(constant matrix Scattering, function scattering) to describe the configuration of a single impurity in GaAs narrow wire. We combine the total scattering-matrix and use Landauer formula to get the conductance. Then we discuss some interesting conductance properties in mesoscopic regime.
Huang, Jun-Xian, and 黃俊憲. "Application of the FDTD Method with the Scattering Matrix in Microwave Circuit Simulation." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/63240379774708142463.
Повний текст джерела國立中山大學
電機工程學系研究所
91
The finite-Difference Time Domain method (FDTD) is to derive the discrete form of the Maxwell’s equations by second-order central difference with the electromagnetic distribution of the Yee space lattice, and computes the value of the electric field and magnetic field in the simulation space by using leapfrog for time derivatives. This method is also different with the frequency domain method which needs to analyze its value individually (ex. Finite Element method). The frequency domain method needs to take a long time for analyzing the response on each spectrum point when the bandwidth is very wide. The advantage of time domain analysis is to obtain the complete frequency response from the simulation value through Fourier Transform method. It’s impossible to combine the electromagnetic analysis with the lumped circuit simulation in current simulation CAD. Thereby the performance of the simulation result and the practical implementation always occurs error because of the lake of the consideration. The FDTD method is the full-wave algorithm which can also simulate the lump element, nonlinear element or active element in simulation space by linking to SPICE or S-parameter. The purpose of this thesis is to develop the method for simulating microwave circuit, and to verify the credibility between the equivalent source method and the S-parameter method in FDTD by the simulation of active antenna and low-noise amplifier.
Xing-Xiang, Liu. "A Study of Surface plasmon Resonance on 3D Metal Spherical Nanoparticles by Multiple Scattering Matrix Method." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0001-1907200615513000.
Повний текст джерелаLiu, Xing-Xiang, and 劉信翔. "A Study of Surface plasmon Resonance on 3D Metal Spherical Nanoparticles by Multiple Scattering Matrix Method." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/52224490597156082783.
Повний текст джерела國立臺灣大學
應用力學研究所
94
In this thesis we theoretically investigate the surface plasmon resonance in metal nanoparticles. We use the multiple scattering method to simulate the electromagnetc propagation and surface plasmon behaviors in particle systems. By this method, the fundamental resonance modes can be clearly resolved. We consider the permittivity functions obtained from the Drude model, experimental results and modification of the size effect. The simulations show that the surface plasmon resonance is greatly influenced by the particle size and arrangement. The enormous field enhancement due to surface plasmon coupling between particles is reported. The interparticle distance and the wave polarization are responsible for the large field magnitude. Finally, we study the plasmon resonance for chains of particles aligned in the polarization and propagating directions. We show the propagation of electromagnetic energy in the chains. These results may improve the development of plasmonic devices.
Loupas, Alexandra Cristina Rodrigues. "Study of Low-energy Electron Collisions with Molecules of Biological Relevance." Doctoral thesis, 2019. http://hdl.handle.net/10362/93349.
Повний текст джерелаSchlosser, Peter [Verfasser]. "Matrix compression methods for the numerical solution of radiative transfer in scattering media / Peter Schlosser." 2003. http://d-nb.info/967305225/34.
Повний текст джерелаHeinemeyer, Eric. "Integral Equation Methods for Rough Surface Scattering Problems in three Dimensions." Doctoral thesis, 2008. http://hdl.handle.net/11858/00-1735-0000-000D-F15F-2.
Повний текст джерелаTiegel, Alexander Clemens. "Finite-temperature dynamics of low-dimensional quantum systems with DMRG methods." Doctoral thesis, 2016. http://hdl.handle.net/11858/00-1735-0000-0028-8801-A.
Повний текст джерела