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 14 of 14 for “"beam alignment"”.
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Beam alignment and image metrology for scanning beam interference lithography : fabricating gratings with nanometer phase accuracy
We are developing a scanning beam interference lithography (SBIL) system. SBIL is capable of producing large-area linear diffraction gratings that are phase-accurate to the nanometer level. Such gratings may enable new paradigms in fields such as semiconductor pattern placement metrology and …
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Enabling dense spatial reuse in millimeter-wave networks
… links that use extremely narrow directional beams. This provides us with a new opportunity to exploit spatial reuse in order to scale network throughput. Exploiting such spatial reuse, however, requires aligning the beams of all nodes in a network. Aligning the beams is a difficult process …
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Millimeter wave communications : from point-to-point links to agile network connections
… radios have to scan the space to find the best alignment between the transmitter's and receiver's beams, a process that takes up to a few seconds. This delay is problematic in a network setting where the base station needs to quickly switch between users and accommodate mobile clients. This …
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Millimeter wave wireless communication: initial acquisition, data communication and relay network investigation
… contributions. First, we propose an efficient beam alignment (BA) scheme for mmWave OFDM (orthogonal frequency division multiplexing) systems. Second, we further explore single-carrier (SC) operation mode at mmWave frequencies and propose a new BA scheme for mmWave SC systems. Third, we define …
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Design and analysis of a scanning beam interference lithography system for patterning gratings with nanometer-level distortions
… The novel patterning method, termed scanning beam interference lithography (SBIL), uses the interference fringes between two coherent laser beams to define highly coherent gratings in photo resist. The substrate is step and scanned under the interference pattern to expose large gratings. Our …
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Software-hardware systems for the Internet-of-Things
… in today's networks: signal blockage and beam alignment. Lastly, this thesis shows how these systems enable new IoT applications, such as untethered high-quality virtual reality. To tackle the energy constraint, this thesis introduces a VLSI chip, which is capable of performing a …
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Low-Energy Electron-Photon Interactions in a Scanning Electron Microscope
… nanostructured interaction regions, and active beam alignment. Chapter 5 explores various experimental results, demonstrating enhanced loss spectroscopy of 2D materials, energy resolution of gold nanoparticle plasmons, as well as spectroscopy of time-tagged cathodoluminescence from optical …
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Microwave accelerating structures: an innovative parallel coupled electron LINAC
… to decoupled propagation axes for RF power and beam it is possible to increase the structure shunt impedance without affecting the cell to cell coupling, combining the advantages of travelling and standing wave structures. Besides in case of a breakdown only the energy stored in one cell is …
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On-Orbit Pointing Risk Mitigation for the Agile MicroSat (AMS) CubeSat Laser Guidestar Payload
… and recharacterize the orientation of the laser beam relative to the spacecraft body. Within the limits of the attitude determination and control system (ADCS), our search mode can accommodate over 1.75° of pointing error during a single pass, and has the capability to search larger areas by …
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Nonlinear Interferometers for Quantum Information Processing and Metrology
… the need for interferometer balancing, beam alignment, and phase stabilization. The simplicity, robustness and versatility of our demonstrated NLI technique illustrates its important role in quantum state engineering and quantum metrology.
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Negative temperature states of bosons in triangular and kagome lattices
… technique which is used for precise lattice beam alignment. The effect of harmonic confinement on band gaps is also considered for lattice depth calibration. Lastly, I present the theory for lattice acceleration experiments which can be used to study Wilson lines and Euler class topology in …
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Development of an automated alignment system for the Magdalena Ridge Observatory Interferometer
… with baselines up to 347 metres. The optical beam trains will deliver light from the telescopes over hundreds of metres in vacuum pipes to a central beam combining laboratory that houses the fringe tracker and science instruments. One major improvement of the MROI over contemporary …
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Design and Optimization of 5G and Beyond Hybrid Communication Systems
… communications, massive MIMO, and hybrid beamforming. We introduce a novel antenna configuration called twin-ULA (TULA) and its composite configurations to generate sharp beams with maximal and uniform gain. We introduce a novel beam alignment technique to maximize the utility of …
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Towards the formation of a forward-boosted beam of neutral antihydrogen for gravitational studies
… the methodology chosen is to create a pulsed beam of antihydrogen atoms, well defined in time, and let it pass through the grids of a moir ́e deflectometer [13] while accelerating because of the influence of the Earth’s gravitational field. By the pattern created by the particles passing …