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 20 for “"Phased array antennas."”.
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Optical feeds for phased array antennas
This thesis investigates optical feed methods for phased array antennas. The technical and practical limitations are analyzed and an optimum design is determined. This optimum optical feed is a two-beam interferometric approach which uses acoustooptic phase control. The theory is derived; a …
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DISTRIBUTED PHASED ARRAY ANTENNAS IN WIDE AREA RFID
… have been used to obtain good coverage with few antennas by making use of multiple spatially distributed antennas and phase dithering. This implements a far-field beamforming that maximises the instantaneous power at a tag. Separately, phased array antennas have also been used to increase the …
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Innovative Tiling Methodologies for the Synthesis of Phased Array Antennas for Advanced Radar and Communications Systems
In this work, the synthesis of clustered phased array antennas characterized by an irregular organization of tiles modules is addressed. By exploiting tiling theorems drawn from the mathematical theory, optimal and sub-optimal methods for the optimization of tiles arrangements and the corresponding …
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Broadband Approaches And Beam-Scanning Techniques For Reflectarray Antenna
<p>Reflectarray antennas combine the numerous advantages of reflector antennas and phased array antennas and create a hybrid high-gain antenna with a low-profile, low-mass, easy-fabrication, and diversified radiation performance. However, it still has some inherent drawbacks, such as limited …
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Design and Analysis of an Electronically Steerable Microstrip Patch and a Novel Coplanar Waveguide (CpW) Fed Slot Antenna Array
<p>Conformal Phased Array Antennas (CPAAs) are very attractive for their high gain, low profile, and beam scanning ability while being conformal to their mounting surface. Among them are microstrip patch phased arrays and wideband slot phased arrays which are of particular significance.</p> <p>In …
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Optimization of Aperiodically Spaced Antenna Arrays for Wideband Applications
Over the years, phased array antennas have provided electronic scanning with high gain and low sidelobe levels for many radar and satellite applications. The need for higher bandwidth as well as greater scanning ability has led to research in the area of aperiodically spaced antenna arrays. …
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An open source array antenna toolbox implementation
… first transmission of radio waves by means of phased array antennas was demonstrated. Since then, the further development of phased array radars was largely driven from a military point of view, with operational phased array systems implemented as far back as the second World War. In recent …
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Exploring the use of Model-Based Systems Engineering (MBSE) to develop systems architectures in naval ship design
… incorporate the latest in weapons technology, phased array antennas, composite structures, signature reduction, survivability, modularity, power systems, computing systems, and automation. The modem day warship is an exceptionally complex system and the design process is long and intricate, …
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Design and Simulation of a Two-Dimensional Beam Steered Millimeter-Wave Phased Array Antenna at W-Band (75 – 110 GHz, respectively 4 – 2.7 m)
Antennas play a significant role in wireless communication systems and have a direct impact on their performance. In particular, Millimeter-wave systems have gained popularity in the wireless communication sector in response to rising demand for greater throughputs, reduced interference, and …
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Analysis And Design Of Low Profile Multiband Multifunctional Antenna Arrays
Light-weight phased array antennas for aerospace and mobile applications require utilizing the same antenna aperture to provide multiple functions with dissimilar radiation pattern specifications (e.g., multiband operation for communications and tracking). Multi-functional antennas provide …
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New Approach to finding Active Element Patterns for Large Arrays
… to active-element pattern analysis, for large phased array antennas, was created using Floquet's theorem. The classic approach to finding active-element patterns uses a full array simulation that can become slow and produce patterns that are specific to certain elements in the array, though …
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A Comprehensive Investigation of New Planar Wideband Antennas
… wireless communications require wideband antennas to support large number of users and higher data rates. Desirable features of a wideband antenna are low-profile, dual-polarization and wide bandwidth in a compact size. Many existing wideband antennas are large in size and some have only …
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Analysis of infinite arrays of arbitrarily shaped planar radiating elements using a Floquet mode based Method of Moments approach
Large phased array antennas are theoretically capable of delivering the directive gain of similarly sized aperture antennas while offering electronic beam scanning capabilities and greater operational flexibility. Unfortunately, the high cost associated with large phased antenna arrays has limited …
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Digitally controlled microstrip phased array.
Adaptive phased arrays are versatile sensors which adjust themselves automatically and electronically to meet particular constraints. Such a constraint might be to minimise the level of interference or to enhance the desired signals or both simultaneously. This enhanced system performance. These …
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Physical Layer Security in Millimeter-Wave Communication
… quantization errors of the phase shifters in the phased-array antennas. The phase quantization errors have adverse effects on the PLS mmWave communication performances. Lastly, we consider to reduce the hardware costs and simplify the structure complexities of the PLS mmWave communication systems …
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Optimizing resource allocation in large communications satellite constellations
… on highly flexible digital payloads, such as phased array antennas, on-board processing, and adaptive modulation and coding schemes. Several approaches have been proposed to deal with the complexity of the added flexibilities at the spacecraft level. Nevertheless, how to address the …
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Architectures and system design for digitally-enhanced antenna arrays
… and signal processing efforts associated with phased array antennas. Fundamentally, these techniques have served to provide additional levels of convenience and performance over the fully analog counterparts, without specifically addressing the underlying design of the analog hardware aspects …
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Beam-Steerable and Reconfigurable Reflectarray Antennas for High Gain Space Applications
Reflectarray antennas uniquely combine the advantages of parabolic reflectors and phased array antennas. Comprised of planar structures similar to phased arrays and utilizing quasi-optical excitation similar to parabolic reflectors, reflectarray antennas provide beam steering without the need of …
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Unified conformal/nonconformal domain decomposition methods for solving large-scale multi-region electromagnetic problems
… method for simulating large finite semi-periodic arrays. For a plane wave incident on a planar boundary at a certain specified angle, this boundary condition can be tuned to be reflectionless for all frequencies and polarizations. Fifth, waveguide modal fields are employed to expand the dual …
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Liquid Crystal Optics For Communications, Signal Processing And 3-d Microscopic Imaging
… communications, photonic control techniques for phased array antennas and radar, and 3-D microscopic imaging. At the heart of the applications demonstrated in this thesis are LC devices that are non-pixelated and can be controlled either electrically or optically. Instead of the typical …