Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 26 for “"Propagation Loss"”.
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A comparison of ASTRAL and RAYMODE propagation loss models and their use in air ASW platforms
… warfare will entail the installation of propagation loss models on ASW aircraft. The decision to put either a range dependent or range independent model in the system will affect the predic
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A numerical method for solving for normal modes with impedance bottom
… of a computer program that calculates the propagation loss for low frequencies in a shallow ocean given the depth of source and receiver, the sound speed profile of the water, the frequency of the source, and the impedance and sound speed in the bottom. The program does this by computing …
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Near-Field Focusing Phased Array for Hyperthermia Application
… the tumor, (ii) deeper penetration depth as the propagation loss in the human body is partially compensated by the beam focusing effect, and (iii) smaller and electronically scannable 3 dB spot.
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Designing Enhanced Nonlinearity in Plasmonic Devices with Epsilon-Near-Zero Films
… used to evaluate effective nonlinear response, propagation loss, and normalized loss-adjusted figures of merit.</p> <p>For the metal-insulator-metal geometry, thinner epsilon-near-zero layers produced larger effective nonlinear coefficients, with the 5 nm silver–indium tin oxide case reaching …
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Modified chalcogenide glasses for optical device applications
… The writing parameters for the minimum propagation loss of 1.47 dB/cm are 0.36 µJ pulse energy and 50 µm/s scanning speed. The observation of spectral broadening in these waveguides indicates that they may have applications for nonlinear optical devices. Fs laser written waveguides in …
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Investigations of the cascade of Langmuir wave turbulence over HAARP Observatory in Gakona, Alaska
… frequency mismatch effect, has to overcome the propagation loss of the mother Langmuir wave in each cascade step. It is known, in general, that the resonant cascade process requires less thresholds than those of the non-resonant cascade process. Thorough analysis concludes that resonant decay is …
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Direct UV writing of structures in lithium niobate and lithium tantalate
… were characterised using mode profiles, propagation losses, numerical aperture and refractive index measurements. In z-cut congruent lithium niobate, waveguides were written on the +z and -z faces producing structures that guided TM polarisation only with +z face waveguides exhibiting the …
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First Demonstration of beta-phase Gallium Oxide Optical Waveguide in Visible-UV Spectrum
… chemical vapor deposition (MOCVD). Their propagation losses in the visible spectrum were comprehensively studied via experiments and simulations of the finite difference method by varying the dimensions of the waveguides. The fabrication process of the waveguides was shown and their …
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Techniques for Reliability and Robustness in Integrated Electronic and Photonic Systems
… selection of cut-back test structures and for propagation loss estimation with a Bayesian prior distribution for fiber-coupling error. Finally, a robust Bayesian optimization algorithm using a new tunable acquisition function is presented for photonic component design. The methods developed in …
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A Turbo Approach to Distributed Acoustic Detection and Estimation
… acoustic multi-sensor networks. An iterative, lossless data fusion algorithm was presented as the model for simulation development. The arrangement and orientation of objects in the simulation environment, as well as most other system parameters are defined by the user before the simulation …
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Studies of advanced integrated nano-photonic devices in silicon
… devices, due to its high-index contrast and low propagation loss at telecom wavelengths. The current thesis presents recent advances in demonstrating discrete components built in silicon-on-insulator (SOI) platforms, around 1550 nm, that can be used as building blocks for future EPIC systems. The …
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Fabrication and applications of fluorescent polymer fibres
… filled with dye or polymer solutions. Two propagation loss mechanisms have been identified; with a fast initial loss attributed to untrapped light, then a slower decay due to self-absorption and other loss processes. These structures exhibited concentration ratios in the region of 20-50.
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Fabrication and characterization of silicon nitride thin film planar waveguides produced by RF magnetron sputtering technique
… this fabrication was to investigate the optical propagation and to measure the propagation loss using prism coupling technique. The optical properties and thickness was determined first using spectroscopic ellipsometry technique. The thickness of waveguide was intended to greater than 400 nm as a …
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Monolithic electronic-photonic integration in state-of-the-art CMOS processes
… with integrated waveguides with 3.7 dB/cm propagation loss alongside unmodified electronics with less than 5 ps inverter stage delay serves as a proof-of-concept for this approach. Demonstrated photonic devices include high-extinction carrier-injection modulators, 8-channel wavelength …
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Metal-insulator-insulator-metal plasmonic waveguides and devices
… vector in its dispersion curve and an increased propagation loss. The MIM radiative SPPs are probed using attenuated total reflection in the Kretschmann configuration and using free space coupling. Both single- and double-sided leaky waves are analyzed. The leaky wave dispersion relation and its …
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3-D optical waveguide arrays for in-vivo optogenetics : development and application
… insertable silicon probes. The waveguides have a propagation loss of-0.4 dB/cm. Right-angle corner mirrors were fabricated at the outputs of the waveguides with losses measured to be 1.5 ± 0.4 dB. Silicon MEMS techniques were developed to fabricate both single- and multi-shank probe geometries …
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Flexible Polymer Waveguides for High-Speed Short-Reach Links
… performance including bending and twisting loss, crosstalk, bandwidth and mode coupling behaviour hasn’t been studied in detail when the flexure is applied to the waveguide. This research quantifies those performances when flexible polymer waveguides are being flexed and provides a useful …
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Numerical Modelling of Plasmonic Waveguides
… parameters are the real effective index, propagation length, and lateral mode radius 3db- addition, the figure of merit (FOM), defined as the ratio between propagation length and lateral mode radius, is also studied. The analysis is performed for different channel plasmon polariton (CPP) …
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Acoustic diffraction from a semi-infinite elastic plate under arbitrary fluid loading with application to scattering from Arctic ice leads
… problem relates to issues in long range sound propagation through partially ice-covered Arctic waters, where open leads or polynya on the surface represent features from which acoustic energy can be diffracted or scattered. This work focusses on ice as the material for the elastic plate …
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Numerical modelling of optical micro-cavity ring resonators for WDM networks
… approach in many studies. Although, their low propagation loss, and low dispersion, they suffers from high power losses at sharp bends. For this reason, large radius of curvature is required in order to achieve high efficiency and compromise the high level of integration. For the purpose of …
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