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 29 for “"Linear Arrays."”.
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Supramolecular Assemblies: Dendrimers, Linear Arrays, and Polypseudorotaxanes
… by 1H NMR spectroscopy and mass spectrometry. Linear supramolecular pseudorotaxane polymers were formed with reversible chain extension in solution by self-assembly of two complimentary homoditopic molecules with secondary ammonium ion and dibenzo-24-crown-8 moieties. The fraction of the cyclic …
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Fabrication and measurement of linear arrays of quantum dots
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.
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An iterative technique for shaped-beam synthesis of unequally spaced, nonuniformly excited linear arrays
… of unequally spaced, nonuniformly excited linear arrays. The technique requires an initial approximation to the desired radiation pattern. This approximation may be attained by any classical synthesis method. Successive iterations are then applied to the initial pattern and are of two …
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Design, diagnosis and reconfiguration of defect-tolerant VLSI
… design and reconfiguration of defect-tolerant linear arrays, (2) diagnosis and reconfiguration of memory chips with spare rows/columns, and (3) optimal diagnosis procedures for k-out-of-n structures.
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Sensor Array Processing with Manifold Uncertainty
… In this thesis, array manifold ambiguities for linear arrays of omni-directional sensors in non-dispersive fields are considered. </p><p>First, the problem of underwater a hydrophone array towed behind a maneuvering platform is considered. The array consists of many hydrophones mounted to a …
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High-power semiconductor laser arrays by metalorganic chemical vapor deposition
… which have led to the fabrication of large linear arrays capable of high power operation.
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Analysis and Synthesis of a New Class of Low Side Lobe Planar Arrays
Numerical techniques for designing planar arrays with low side lobe level often require memory intensive optimization algorithms and also initialization in the form of some known values of radiation pattern parameters beforehand - information that may not be available when designing arrays. A few …
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Optimal linear array heading in a directional noise field
… the signal-to-noise ratio (SNR) detected by a linear array in a directional ambient noise field. The SNR can be optimized by minimizing the ambient noise detected by the array. For a given target location, each possible heading of the array centers the ambiguous beam of the array at a different …
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Multi Array, Conformable Ultrasound Patch for Soft Tissue Imaging
… made in various configurations from dense 2-D arrays for volumetric imaging to single element needle like transducers for intravascular imaging. The performance of an ultrasound transducer is dictated by the properties of the piezoelectric material being used. One current drawback to ultrasound …
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Nanostructuring with diblock copolymers
… - Pattering of dense-packed gold clusters into linear arrays and subsequent fusion by electroless growth - Formation and deposition of cylindrical micelles as flexible templates for nano-wire growth
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Synthesis of Ultra-Wideband Array Antennas
… Factors contributing to bandwidth limitation of arrays include array factor, radiation characteristics of the array element, and inter-element mutual coupling. Strictly speaking, distortion-free transmission or reception of ultra-wideband signals can be maintained if the magnitude of the radiated …
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Randomly Spaced Smart Antennas
… presented so far for non-equidistant antenna arrays have been restricted to the analysis of symmetric or linear geometries. Several direction of arrival (DOA) and adaptive beamforming al- gorithms are implemented and analyzed for both linear and planar randomly spaced antenna configurations; …
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Substrate Integrated Waveguide Horn Slot Antenna Array
… which is synthesized in a planar substrate with arrays of metallic vias to realize bilateral side walls and its transitions with planar structures. These vias act as walls of the waveguide supporting current flow, thus allowing for waveguide mode propagation. Substrate integrated waveguide is …
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Efficient Array Processing for Partial Signal Coherence
With the growing use of antenna arrays for enhancing signal detection, estimation, interference cancellation, and position location comes the need to better understand the spatial properties of the received signals. To allow for simple and efficient implementation required in real-time processing …
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Phased Array Beamsteering in Composite Laminates for Guided Wave Structural Health Monitoring
… for beamsteering in certain directions with a linear array and performance similar or even better than the isotropic case. However, the useful range of angles with a 1-D linear array for anisotropic wave modes is quite small and other directions exhibit undesired grating lobes and large …
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Innovative Techniques for Antenna Synthesis in Modern Wireless Communication Systems
… a methodology for the design of aperiodic UWB linear arrays populated by spline-shaped radiating elements is proposed. Successively, the design of an array of UWB elements for imaging applications is described. In order to assess the effectiveness as well as the reliability of the proposed …
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Four Branch Diversity Combining and Adaptive Beamforming Measurements Using Mobile Arrays at 2.05 GHz
Mobile arrays employing diversity combining and adaptive beamforming techniques overcome multipath fading, improve coverage, and increase capacity in wireless communications systems. In this thesis, diversity combining and adaptive beamforming performance of different four element arrays for mobile …
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A novel technique for phased array receivers based on an economic sampling scheme
… signal in the frequency domain is derived for a linear array. The radiation pattern and the received signals are simulated for equally spaced planar and linear arrays. Bandwidth signal transmission is demonstrated and tapering effects are shown. After that, the proposed technique is expanded for …
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On the synthesis of optimum monopulse antenna array distributions
… antennas of high performance. For this reason arrays are finding increasing application as monopulse antennas. A new exact procedure is introduced for the synthesis of optimum difference distributions for linear arrays of discrete elements, with a maximum sidelobe level specification. The …
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