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Showing 1 to 20 of 20 for “"Leaky-wave"”.
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Compact Leaky Wave Antenna Using Ferroelectric Materials
Leaky wave antenna continuously attracts a lot interests for tuning the radiation direction over a large angle. Various types of leaky wave antenna have been developed since 1940. However, most of these leaky wave antennas suffered from their excessive volume and the required wide range of …
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High-efficiency Waveguide Tunable Leaky-wave Antennas and Phase-shifters
… one can increase the radiation efficiency of leaky-wave beam-steerable antennas. In this effort, both frequency and fixed frequency scanned leaky-wave antennas are considered. Specifically, we discuss the design and implementation of a slow-wave frequency-scanned leaky-wave antenna that can …
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Analysis and design of hybrid leaky-wave antennas loaded with frequency selective surfaces
… esta tesis se propone una nueva antena de tipo Leaky-Wave (Leaky Wave Antenna, LWA). Estas antenas han recibido mucha atención en las últimas décadas por ser altamente directivas. En concreto, constituyen una solución especialmente atractiva para aplicaciones que requieran altas prestaciones y …
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Advancing 5G Coverage: Novel Methods for Metasurface Characterization and Leaky-Wave Antenna Reconfigurability
… reconstruction and pattern reconfigurability in leaky wave antennas (LWAs). Metasurfaces offer potential coverage enhancement by signal manipulation. The incident field reconstruction method efficiently analyzes and optimizes MSs, addressing traditional limitations. Using numerical superposition …
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Propagation of Leaky Waves in Free Surfaces and Grating Structures on (100)-Cut Gallium-Arsenide
… understand the details of propagation of the leaky wave through metal grating structures in $\{$100$\}$-cut GaAs. This objective was met by first understanding wave propagation in free-surface GaAs and subsequently exploring a buried bimetallic electrode structure which will present minimum …
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Methods in wave propagation and scattering
Aspects of wave propagation and scattering with an emphasis on specific applications in engineering and physics are examined. Frequency-domain methods prevail. Both forward and inverse problems are considered. Typical applications of the method of moments to rough surface three-dimensional (3-D) …
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Interaction of acoustic beam with elastic structures
… been used to elucidate the phenomena of guided wave generation and reradiation by selecting beam incidence at, or near, phase-matching conditions. Under these circumstances reasonant mode conversion of accoustic wave to guided wave mode energy can occur. This interaction has been studied in …
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Metal-insulator-insulator-metal plasmonic waveguides and devices
Metal-insulator-metal (MIM) plasmonic waveguides have been proposed for highly integrated subwavelength structures. In this work, waveguiding and coupling of surface plasmon polaritons (SPPs) within finite planar MIM plasmonic waveguides are examined both theoretically and experimentally. Gain …
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Rectangular Waveguide Filled with Uniaxial Medium and Negative Resistance Enhanced Composite Right/Left-Handed Transmission Line
<p>Two wave-guiding problems are treated in this work. The first part addresses the problem of a rectangular waveguide filled with a uniaxially anisotropic or uniaxial medium. Different orientations of the optic axis of the uniaxial medium are considered and the wave transmission and modal …
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HIGH-PERFORMANCE PERIODIC ANTENNAS WITH HIGH ASPECT RATIO VERTICAL FEATURES AND LARGE INTERCELL CAPACITANCES FOR MICROWAVE APPLICATIONS
… is composed of 3×3 unit cells and shows fast-wave behaviors. Most antenna designs are resonant in nature; however, in one case, a low-profile efficient leaky-wave antenna with scanning radiation pattern is proposed. Several antenna prototypes are fabricated and tested to validate the analyses …
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Design of metasurfaces for detection system application
… both structures and the AMC’s angular stability. Leaky wave antennas are also presented and their surface is tuned to improve their radiation properties and change their polarization. Furthermore, they are designed to be easily manufacturable using additive manufacturing techniques. Curved …
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Developments in time-resolved ultrafast imaging and spectroscopy at terahertz frequencies
… in THz detection methodology, both in a waveguide platform and in a more typical free space geometry. In the waveguide approach, THz generation, detection, and manipulation is self-contained in an on-chip system that we term the polaritonics platform, which simply consists of a single …
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Characteristic Mode Analysis of Crumpled Graphene Flakes and A New Green’s Functions Evaluation Method for Layered Media
… and commercially available electromagnetic wave solvers. The modified Green’s function method, otherwise called as analytical evaluation method, which replaces the tail region of Sommerfeld integrals with its equivalent closed form expressions. Further, a detailed study on the types of …
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Design and applications of smart antenna systems for wireless networks in the context of the Internet of Things (IOT)
… presented in the form of thesis by publication. Leaky-Wave Antennas (LWA) consist on a waveguide structure which allows the leakage of part of the power along the structure. For this reason, the radiation of the antenna is produced by the leakage of power. In order to produce coherent radiation, …
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Novel integral equation methods applied to the analysis of new guiding and radiating structures and optically-inspired phenomena at microwaves
[SPA] En esta tesis doctoral se presenta un trabajo multidisciplinar, en el que se han desarrollado una serie de formulaciones matemáticas aplicadas al análisis eficiente y riguroso de diversas estructuras, dispositivos y fenómenos físicos en el rango frecuencial de las microondas. Los objetivos …