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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Síntese de filtros rejeita-faixa de micro-ondas de banda-larga e dupla-banda empregando estruturas periódicas EBG. / Synthesis methodology for standband filters in microwave for wide stopband and dual stop band using EBG structures.

Cardoso, Marcos Vaz 28 November 2011 (has links)
Esta dissertação de mestrado apresenta um estudo da aplicação de estruturas Electromagnetic Bandgap (EBG) em circuitos planares de micro-ondas, com a proposição de topologias originais de filtros rejeita-faixa de banda ultra-larga e dupla-banda e de uma metodologia de síntese desses filtros. Foi proposta uma metodologia de projeto de filtros EBG, que foi aplicada a um filtro em microlinha de transmissão utilizando duas estruturas EBG simultâneas, com a finalidade de se obter um filtro com banda de rejeição ultra-larga. Esse filtro foi construído em tecnologia planar, tendo demonstrado uma banda de rejeição ultra-larga de 11 GHz centrada em 11,5 GHz, com nível de rejeição superior a 34 dB, apresentando excelente concordância com os resultados de simulação computacional. Paralelamente, foi desenvolvida uma metodologia de síntese que permite a geração automática de novas topologias de filtros rejeita-faixa empregando estruturas EBG que resultem em uma banda larga de rejeição ou com duplas bandas de rejeição. A metodologia de síntese proposta envolve procedimentos computacionais de otimização da geometria das estruturas EBG aplicadas em microlinha de transmissão, visando a obtenção da resposta em frequência de um filtro definida por meio de uma Função Objetivo. Para esse fim empregou-se a ferramenta computacional MATLAB com o toolbox de algoritmos genéticos para desenvolver um programa de otimização, que interage com o simulador eletromagnético tridimensional EM-3D Microwave Suite da CST. O procedimento de síntese desenvolvido foi aplicado ao projeto de um filtro com dupla-banda de rejeição centradas em 3,3 GHz e 7,8 GHz e de três filtros com característica de rejeição em banda ultra-larga, capazes de rejeitar até uma banda de 9 GHz a 20 GHz com rejeição maior que 10 dB. Os filtros projetados foram construídos em tecnologia planar e caracterizados em frequências de micro-ondas. Os resultados experimentais comprovaram a eficácia e flexibilidade da metodologia de síntese proposta, que possibilitou contribuições originais na área de filtros rejeita-faixa usando estruturas EBG, com topologias inéditas. / This dissertation for a Master degree in Engineering, presents a survey of the application of Electromagnetic Bandgap (EBG) structures on microwave planar circuits, with the conception of original topologies for wide stopband and dual stopband filters, and the proposition of a synthesis methodology for these filters. A filter design methodology was proposed and applied to the design of a transmission line filter using two simultaneous EBG structures, aiming at the achievement of a filter with a wide stop-band. This filter was built in planar circuit technology, with the demonstration of an 11 GHz ultra-wide stopband centered in 11.5 GHz, with high degree of rejection superior than 34 dB, presenting excellent agreement with the computational simulation. In parallel, a synthesis methodology was developed to automatically generate new topologies of stopband filters using EBG structures, that results in filters with wide stopband or dual stop-bands. The proposed synthesis methodology involves computational processes for the optimization of the EBG structure geometry applied to microwave transmission line, aiming at achieving the filter response defined by an objective function. For that, the software MATLAB with the genetic algorithm toolbox was used to develop an optimization program, which interacts with the tridimensional electromagnetic simulator EM-3D Microwave Suite from CST. The synthesis procedure was applied to the project of one filter with dual stopband centered in 3.3 GHz and 7.8 GHz and to the project of three filters with an wide stopband feature capable of rejecting a frequency band from 9 GHz to 20 GHz with magnitude of rejection greater than 10 dB. The designed filters were built in planar technology and measured at microwave frequencies. The experimental results demonstrated the effectiveness and the flexibility of the proposed synthesis methodology, which allowed original contributions in the field of stopband filters using EBG structures, with novel topologies.
2

Síntese de filtros rejeita-faixa de micro-ondas de banda-larga e dupla-banda empregando estruturas periódicas EBG. / Synthesis methodology for standband filters in microwave for wide stopband and dual stop band using EBG structures.

Marcos Vaz Cardoso 28 November 2011 (has links)
Esta dissertação de mestrado apresenta um estudo da aplicação de estruturas Electromagnetic Bandgap (EBG) em circuitos planares de micro-ondas, com a proposição de topologias originais de filtros rejeita-faixa de banda ultra-larga e dupla-banda e de uma metodologia de síntese desses filtros. Foi proposta uma metodologia de projeto de filtros EBG, que foi aplicada a um filtro em microlinha de transmissão utilizando duas estruturas EBG simultâneas, com a finalidade de se obter um filtro com banda de rejeição ultra-larga. Esse filtro foi construído em tecnologia planar, tendo demonstrado uma banda de rejeição ultra-larga de 11 GHz centrada em 11,5 GHz, com nível de rejeição superior a 34 dB, apresentando excelente concordância com os resultados de simulação computacional. Paralelamente, foi desenvolvida uma metodologia de síntese que permite a geração automática de novas topologias de filtros rejeita-faixa empregando estruturas EBG que resultem em uma banda larga de rejeição ou com duplas bandas de rejeição. A metodologia de síntese proposta envolve procedimentos computacionais de otimização da geometria das estruturas EBG aplicadas em microlinha de transmissão, visando a obtenção da resposta em frequência de um filtro definida por meio de uma Função Objetivo. Para esse fim empregou-se a ferramenta computacional MATLAB com o toolbox de algoritmos genéticos para desenvolver um programa de otimização, que interage com o simulador eletromagnético tridimensional EM-3D Microwave Suite da CST. O procedimento de síntese desenvolvido foi aplicado ao projeto de um filtro com dupla-banda de rejeição centradas em 3,3 GHz e 7,8 GHz e de três filtros com característica de rejeição em banda ultra-larga, capazes de rejeitar até uma banda de 9 GHz a 20 GHz com rejeição maior que 10 dB. Os filtros projetados foram construídos em tecnologia planar e caracterizados em frequências de micro-ondas. Os resultados experimentais comprovaram a eficácia e flexibilidade da metodologia de síntese proposta, que possibilitou contribuições originais na área de filtros rejeita-faixa usando estruturas EBG, com topologias inéditas. / This dissertation for a Master degree in Engineering, presents a survey of the application of Electromagnetic Bandgap (EBG) structures on microwave planar circuits, with the conception of original topologies for wide stopband and dual stopband filters, and the proposition of a synthesis methodology for these filters. A filter design methodology was proposed and applied to the design of a transmission line filter using two simultaneous EBG structures, aiming at the achievement of a filter with a wide stop-band. This filter was built in planar circuit technology, with the demonstration of an 11 GHz ultra-wide stopband centered in 11.5 GHz, with high degree of rejection superior than 34 dB, presenting excellent agreement with the computational simulation. In parallel, a synthesis methodology was developed to automatically generate new topologies of stopband filters using EBG structures, that results in filters with wide stopband or dual stop-bands. The proposed synthesis methodology involves computational processes for the optimization of the EBG structure geometry applied to microwave transmission line, aiming at achieving the filter response defined by an objective function. For that, the software MATLAB with the genetic algorithm toolbox was used to develop an optimization program, which interacts with the tridimensional electromagnetic simulator EM-3D Microwave Suite from CST. The synthesis procedure was applied to the project of one filter with dual stopband centered in 3.3 GHz and 7.8 GHz and to the project of three filters with an wide stopband feature capable of rejecting a frequency band from 9 GHz to 20 GHz with magnitude of rejection greater than 10 dB. The designed filters were built in planar technology and measured at microwave frequencies. The experimental results demonstrated the effectiveness and the flexibility of the proposed synthesis methodology, which allowed original contributions in the field of stopband filters using EBG structures, with novel topologies.
3

New multi-standard dual-wideband and quad-wideband asymmetric step impedance resonator filters with wide stop band restriction

Al-Yasir, Yasir I.A., Tu, Yuxiang X., Ojaroudi Parchin, Naser, Abdulkhaleq, Ahmed M., Kosha , Jamal S.M., Ullah, Atta, Abd-Alhameed, Raed, Noras, James M. 28 September 2023 (has links)
Yes / New multi-standard wide band filters with compact sizes are designed for wireless communication devices. The proposed structures realize dual-wideband and quad-wideband characteristics by using a new skew-symmetrical coupled pair of asymmetric stepped impedance resonators, combined with other structures. The first and second dual-wideband filters realize fractional bandwidths (FBW) of 43.2%/31.9% at the central frequencies (CF) of 1.875/1.63 GHz, and second bandwidths of 580 MHz/1.75 GHz at CF of 5.52/4.46 GHz, respectively. The proposed quad-band filter realizes its first/second/third/fourth pass bands at CF 2.13/5.25/7.685/9.31 GHz with FBW of 46.0%/11.4%/4.6%and 5.4%, respectively. The wide pass bands are attributed to the mutual coupling of the modified ASIR resonators and their bandwidths are controllable by tuning relative parameters while the wide stop band performance is optimized by the novel interdigital cross coupled line structure and parallel uncoupled microstrip line structure. Moreover, the quad band is generated by introducing the novel defected rectangle structure. These multi-standard filters are simulated, fabricated and measured, and measured results agree well with both simulated results and theory predictions. The good in-band and out-of-band performances, the miniaturized sizes and simple structures of the proposed filters make them very promising for applications in future multi-standard wireless communication. / Horizon 2020 Framework Programme(European Union), Grant/Award Number:H2020-MSCA-ITN-2016 SECRET-722 424
4

Technology and properties of InP-based photonic crystal structures and devices

Shahid, Naeem January 2012 (has links)
Photonic crystals (PhCs) are periodic dielectric structures that exhibit a photonic band gap; a range of wavelengths for which light propagation is forbidden. 2D PhCs exhibit most of the properties as their three dimension counterparts with a compatibility with standard semiconductor processing techniques such as epitaxial growth, electron beam lithography, Plasma deposition/etching and electromechanical lapping/polishing. Indium Phosphide (InP) is the material of choice for photonic devices especially when it comes to realization of coherent light source at 1.55 μm wavelength. Precise engineering of the nanostructures in the PhC lattice offers novel ways to confine, guide and control light in phonic integrated circuits (PICs). Strong confinement of light in PhCs offer novel opportunities in many areas of physics and engineering. Dry etching, a necessary process step in PhC device manufacturing, is known to introduce damage in the etched material. Process induced damage and its impact on the electrical and optical properties of PhCs depends on the etched material, the etching technique and process parameters. We have demonstrated a novel post-etch process based on so-called mass-transport (MT) technology for the first time on InP-based PhCs that has significantly improved side-wall verticality of etched PhC holes. A statistical analysis performed on several devices fabricated by MT process technology shows a great deal of improvement in the reliability of optical transmission characteristics which is very promising for achieving high optical quality in PhC components. Several PhC devices were manufactured using MT technology. Broad enough PhC waveguides that operate in the mono/multi-mode regime are interesting for coarse wavelength de-multiplexing. The fundamental mode and higher order mode interaction creates mini-stop band (MSB) in the dispersion diagram where the higher order mode has a lower group velocity which can be considered as slow light regime. In this thesis work, the phenomena of MSBs and its impact on transmission properties have been evaluated. We have proposed and demonstrated a method that enables spectral tuning with sub-nanometer accuracy which is based on the transmission MSB. Along the same lines most of the thesis work relates to broad enough PhC guides that operated in the multimode regime. Temperature tuning experiments on these waveguides reveals a clear red-shift with a gradient of dλ/dT=0.1 nm/˚C. MSBs in these waveguides have been studied by varying the width in incremental amounts. Analogous to semiconductors heterostructures, photonic heterostructures are composed of two photonic crystals with different band-gaps obtained either by changing the air-fill factor or by the lattice constant. Juxtaposing two PhC and the use of heterostructures in waveguide geometry has been experimentally investigated in this thesis work. In particular, in multimode line defect waveguides the “internal” MSB effect brings a new dimension in single junction-type photonic crystal waveguide (JPCW) and heterostructure W3 (HW3) for fundamental physics and applications. We have also fabricated an ultra-compact polarization beam splitter (PBS) realized by combining a multimode waveguide with internal PhC. MSBs in heterostructure waveguides have shown interesting applications such as designable band-pass flat-top filters, and resonance-like filters with high transmission. In the course of this work, InGaAsP suspended membrane technology was developed. An H2 cavity with a linewidth of ~0.4 nm, corresponding to a Q value of ~3675 has been shown. InGaAsP PhC membrane is an ideal platform to study coupled quantum well/dot-nanocavity system. / <p>QC 20120831</p>
5

Design, modelling and implementation of several multi-standard high performance single-wideband and multi-wideband microwave planar filters

Tu, Yuxiang X. January 2016 (has links)
The objectives of this work are to review, investigate and model the microwave planar filters of the modern wireless communication system. The recent main stream of microwave filters are classified and discussed separately. Various microwave filters with detailed applications are investigated in terms of their geometrical structures and operational performances. A comprehensive theoretical study of microwave filters is presented. The main types of microwave filters including the basic low-pass filters such as Butterworth and Chebyshev filters are fully analysed and described in detail. The transformation from low-pass prototype filters to high-pass filters, band-pass filters and band-stop filters are illustrated and introduced. Research work on stepped impedance resonator (SIR) and asymmetric stepped impedance resonator (ASIR) structure is presented. The characteristics of λg/4, λg/2 and λg (λg is the guided wavelength of the fundamental frequency in the free space) type SIR resonators, and the characteristic of asymmetric SIR resonator are categorized and investigated. Based on the content mentioned above, novel multi-standard high performance asymmetric stepped impedance resonator single-wideband and dual-wideband filters with wide stopbands are proposed. The methodologies to realize wide passband and wide stop-band filters are detailed. In addition, multi-standard high performance triplewideband, quadruple-wideband and quint-wideband filters are suggested and studied. The measurement results for all prototype filters agree well with the theoretical predictions and simulated results from Ansoft HFSS software. The featured broad bandwidths over single/multiple applicable frequency bands and the high performances of the proposed filters make them very promising for applications in future multistandard wireless communication.
6

Design and Implementation of Fully Integrated CMOS On-chip Bandpass Filter with Wideband High-Gain Low Noise Amplifier

Wang, Yu 20 August 2021 (has links)
No description available.
7

Design, Modelling and Implementation of Several Multi-Standard High Performance Single-Wideband and Multi-Wideband Microwave Planar Filters

Tu, Yuxiang X. January 2016 (has links)
The objectives of this work are to review, investigate and model the microwave planar filters of the modern wireless communication system. The recent main stream of microwave filters are classified and discussed separately. Various microwave filters with detailed applications are investigated in terms of their geometrical structures and operational performances. A comprehensive theoretical study of microwave filters is presented. The main types of microwave filters including the basic low-pass filters such as Butterworth and Chebyshev filters are fully analysed and described in detail. The transformation from low-pass prototype filters to high-pass filters, band-pass filters and band-stop filters are illustrated and introduced. Research work on stepped impedance resonator (SIR) and asymmetric stepped impedance resonator (ASIR) structure is presented. The characteristics of λg/4, λg/2 and λg (λg is the guided wavelength of the fundamental frequency in the free space) type SIR resonators, and the characteristic of asymmetric SIR resonator are categorized and investigated. Based on the content mentioned above, novel multi-standard high performance asymmetric stepped impedance resonator single-wideband and dual-wideband filters with wide stopbands are proposed. The methodologies to realize wide passband and wide stop-band filters are detailed. In addition, multi-standard high performance triplewideband, quadruple-wideband and quint-wideband filters are suggested and studied. The measurement results for all prototype filters agree well with the theoretical predictions and simulated results from Ansoft HFSS software. The featured broad bandwidths over single/multiple applicable frequency bands and the high performances of the proposed filters make them very promising for applications in future multistandard wireless communication.
8

Numerical Investigation of the Nonlinear Dynamics of a Hybrid Acousto-Optic Bragg Cell with a Variable Feedback Gain

Zhou, Hao 26 August 2014 (has links)
No description available.
9

Microwave Filters in Planar and Hybrid Technologies with Advanced Responses

Marín Martínez, Sandra 31 October 2022 (has links)
[ES] La presente tesis doctoral tiene como principal objetivo el estudio, diseño, desarrollo y fabricación de nuevos dispositivos pasivos de microondas, tales como filtros y multiplexores con respuestas avanzadas para aplicaciones de alto valor añadido (i.e. comerciales, militares, espacio); orientados a distintos servicios, actuales y futuros, en sistemas inalámbricos de comunicación. Además, esta investigación se centrará en el desarrollo de filtros encapsulados de montaje superficial y con un elevado grado de miniaturización. Para ello, se propone investigar distintas técnicas que consigan respuestas muy selectivas o con unas características exigentes en rechazo (mediante la flexible introducción de ceros de transmisión), así como una excelente planaridad en banda (aplicando técnicas tales como la mejora del Q o el diseño de filtros con pérdidas, lossy filters), obteniendo de este modo respuestas mejoradas, con respecto a soluciones conocidas, en los componentes de microondas desarrollados. De forma general, la metodología seguida se iniciará con una búsqueda y conocimiento del estado del arte sobre cada uno de los temas que se acometerán en esta tesis. Tras ello, se establecerá un procedimiento de síntesis que permitirá acometer de forma teórica los objetivos y especificaciones a conseguir en cada caso. Con ello, se establecerán las bases para iniciar el proceso de diseño, incluyendo co-simulación circuital/electromagnética y optimización que permitirán, en última instancia, implementar la solución planteada en cada caso de aplicación concreto. Finalmente, la demostración y validez de todas las investigaciones realizadas se llevará a cabo mediante la fabricación y caracterización experimental de distintos prototipos. / [CA] La present tesi doctoral té com a principal objectiu l'estudi, disseny, desenvolupament I fabricació de nous dispositius passius de microones, com ara filtres i multiplexors amb respostes avançades per a aplicacions d'alt valor afegit, (comercials, militars, espai); orientats a oferir diferents serveis, actuals i futurs, en els diferents sistemes sense fils de comunicació. A més, aquesta investigació es centrarà en el desenvolupament de filtres encapsulats de muntatge superficial i amb un elevat grau de miniaturització. Per a això, es proposa investigar diferents tècniques que aconsegueixin respostes molt selectives o amb unes característiques exigents en rebuig (mitjançant la flexible introducció de zeros de transmissió), així com una excel·lent planaritat en banda (aplicant tècniques com ara la millora de l'Q o el disseny de filtres amb perdues, lossy filters), obtenint d'aquesta manera respostes millorades, respecte solucions conegudes, en els components de micrones desenvolupats. De forma general, la metodologia seguida s'iniciarà amb una recerca i coneixement de l'estat de l'art sobre cadascun dels temes que s'escometran en aquesta tesi. Després d'això, s'establirà un procediment de síntesi que permetrà escometre de forma teòrica els objectiusi especificacions a aconseguir en cada cas. Amb això, s'establiran les bases per iniciar el procés de disseny, amb co-simulació circuital / electromagnètica i optimització que permetran, en última instància, implementar la solució plantejada en cada cas d'aplicació concret. Finalment, la demostració i validesa de totes les investigacions realitzades es durà a terme mitjançant la fabricació i caracterització experimental de diferents prototips. / [EN] The main objective of this doctoral thesis is the study, design, development and manufacture of new passive microwave components, such as filters and multiplexers with advanced responses for commercials, military and space applications; oriented to other different services, in current and future wireless communication systems. In addition, this research will focus on the development of surface-mounted encapsulated filters with a high degree of miniaturization. With this purpose, it is proposed to investigate different techniques that achieve highly selective responses or with demanding characteristics in rejection (through the flexible introduction of transmission zeros), as well as an excellent in-band planarity (applying techniques such as the Q enhancement or lossy filters), thus obtaining improved responses, with respect to known solutions, in the developed microwave components. In general, the followed methodology will begin with a search and knowledge of the state of the art on each of the topics addressed in this thesis. After that, a synthesis procedure will be established, which will allow the achievement of the objectives and specifications in a theoretical way, for each case. With this, the bases will be established to start the design process, with circuital and electromagnetic co-simulations and optimizations that will allow, ultimately, to implement the proposed solution, in every application case, specifically. Finally, the demonstration and validity of all the investigations will be carried out through the manufacture and experimental characterization of different prototypes. / Marín Martínez, S. (2022). Microwave Filters in Planar and Hybrid Technologies with Advanced Responses [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/188943

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