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 299 for “"Reflector"”.
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Selected Reflector Antenna Studies
… studies some of the current research topics in reflector antennas. The topics dicussed are reflector surface distortion, compensation and detection; reflector near-field analysis; and reflector antenna surface shaping. Each chapter of the thesis covers one topic and is self-contained. The most …
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Multiple reflector scanning antennas
… is, of course, also very important. Traditional reflector systems employing the well-focused paraboloidal-shaped main reflector accomplish scan by motion of a few feeds, or by phase steering a focal plane feed array. Such scanning systems can experience significant gain loss. Traditional …
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Multiple feed reflector antenna analysis
… method of calculating the secondary pattern of a reflector illuminated by a feed array is developed. Geometrical optics is used to determine the incident field via a coordinate transformation approach. The incident field from each element is superimposed to form the total field used in finding the …
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Inline microring reflector for photonic applications
… and simulations of a compact microring based reflector assembled by forming a Bragg grating into a loop. With the appropriate design, the microring resonance can precisely align with the reflection peak of the grating while all other peaks are suppressed by reflection nulls of the grating. The …
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Integrated reflector antenna design and analysis
Reflector antenna design is a mature field and most aspects of it have been studied. However, most previous work is distinguished by the fact that it is narrow in scope, analyzing only a particular problem under certain conditions. Methods of analysis of this type are not useful for working on …
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Tolerance analysis of synthesized dual-reflector antennas
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1993.
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Adaptive Pattern Modeling for Large Reflector Antennas
… of large axisymmetric paraboloidal focus-fed reflector antenna systems. The intended application of these methods is to improve the performance of time-domain interference canceling (TDC) in radio astronomy. The first method yields a closed-form expression for the antenna pattern with …
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Investigation of a flexible inextensible composite membrane reflector
… A prototype membrane employed as a parabolic reflector antenna was fabricated and subsequently evaluated in terms of its functional performance. In constructing the prototype, many challenging and complex conceptual, analytical, and design problems arose and were resolved. In particular, the …
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Electron-reflector strategy for CdTe thin-film solar cells
… gap (1.5 eV). The incorporation of an electron reflector is a strategy to improve the open-circuit voltage of solar cells, and thus a strong possibility to improve the efficiency of CdTe thin-film solar cells. An electron reflector is a conduction-band energy barrier at the back surface of the …
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Analysis of reflector antenna systems for wide-angle scanning
ETDs are only available to UIUC Users without author permission
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Development of Electrodes for an Electrostatically Actuated Mesh Reflector
… actuators can enable radio frequency (RF) reflectors with previously inaccessible combinations of size and surface precision. A candidate approach for distributed actuation in large space structures is macroscale electrostatic actuation, which offers advantages in low power, high bandwidth, …
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Bragg reflector geometries for colorimetric orientation and deformation sensing
… and the combination of conformal and flat Bragg reflectors in order to identify suitable cavity designs. A MATLAB-based simulation environment was created to estimate the surfaces' intensity profile in monochromatic light and color chromaticity under any illumination source and incidence angle as …
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Modification of Large Reflector Antennas for Low Frequency Operation
Modifications of large reflector antennas, such that their observing capabilities are enhanced in the range of about 10-500~MHz without affecting operation of the pre-existing higher-frequency systems, are addressed in this dissertation. The major contributions of this dissertation can be divided …
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Beam scanning offset Cassegrain reflector antennas by subreflector movement
… for the mission was a wide scanning, high gain reflector antenna system for use in radiometric remote sensing from geostationary orbit. This work describes research conducted at Virginia Tech into techniques for beam scanning offset Cassegrain reflector antennas by subreflector translation and …
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Surface -Etched Distributed Bragg Reflector Lasers in Photonic Integrated Circuits
A high-power DBR laser array is also presented for use in spectral beam combining systems. The laser structure for this application is engineered for high-power applications. The engineering of the lateral optical guiding structure as well as the surface-etched grating is discussed.
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A Reflector Antenna Corrected for Spherical, Coma, and Chromatic Aberrations
Made available in DSpace on 2014-12-10T19:06:44Z (GMT). No. of bitstreams: 1 7121200.pdf: 4113603 bytes, checksum: 574e2ce2f80af0867718d49876bdda73 (MD5) Previous issue date: 1971
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Bragg reflector thin-film resonators for miniature PCS bandpass filters
… limited by the AlN film quality. Several Bragg Reflector TFR devices were fabricated and tested. Sputtered SiO2 and AINOx were used as the low and high acoustic impedance materials respectively. The best devices have a bandwidth of approximately 3.6%, or 25MHz and a Q of 400. The low figures of …
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A high gain tri-reflector antenna configuration for beam scanning
… following work is concerned with the design of a reflector antenna configuration for passive remote sensing and suitable for use on a geostationary platform; however, the resultant configuration is not limited to this application. The specific goal is the design of a reflector antenna …
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Fabrication and measurements of surface-etched grating distributed Bragg reflector laser
… gain is relatively broad, so a distributed Bragg reflector (DBR) laser is used to make a narrow linewidth laser. The thesis discusses semiconductor lasers that use surface-etched DBR along with the physics of both the semiconductor and the DBR laser. The topics addressed are the fabrication of the …
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