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 38 for “"high power microwave"”.
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Anode Materials for High Power Microwave Devices
… energy relates to devices capable of generating highly focused energy sources, including lasers, particle beams and microwaves. Extensive research is continuingly conducted into such devices’ frequency spectrum in order to increase their power levels to develop new applications. However, one area …
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High Power Microwave Generation for Advanced Particle Acceleration
… the experimental demonstration of advanced high power microwave sources for application to high gradient particle accelerators. The major effort was directed at the design and successful test of a metamaterial-based power extractor at the Argonne Wakefield Accelerator (AWA). We obtained up …
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Thermal and mechanical analysis of high power microwave windows
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1995.
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A High Power Microwave Zoom Antenna With Metal Plate Lenses
A high power microwave antenna with true zoom capability was designed and constructed with the use of metal plate lenses. Proof of concept was achieved through experiment as well as simulation. This concept comprises a horn feed antenna and two metal plate lenses. Good agreement was found between …
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Modulation-Doped Field-Effect Transistors for High-Power Microwave Applications
… and sequential wet and dry selective etching. A high linearity of device characteristics is important to minimize intermodulation of high frequency signals under high-power operation. The linearity of device performance is investigated through the comparison of InGaAs/GaAs PHEMTs and doped …
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Metamaterial structures for Wakefield acceleration and high power microwave generation
… for two applications: wakefield acceleration and high power microwave generation. Under the topic of wakefield acceleration, on the theoretical side, several metamaterial structures have been designed and simulated. The novel phenomenon of reversed Cherenkov radiation has been found to enhance the …
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Generation of coherent high-power microwave radiation with relativisitic electron beams
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Physics, 1994.
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Computational analyses of high power microwave slotted array antennas for mobile applications
Computational Analyses of High Power Microwave Slotted Array Antennas for Mobile Applications
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High power microwave generation using an active metamaterial powered by an electron beam
… and experimental demonstration of coherent microwave generation at 2.4 GHz in a metamaterial loaded waveguide using a 490 keV, 84 A, one microsecond pulse length electron beam that produced more than 5 MW of microwave power. Three different metamaterial structure designs named MTM1, MTM2, …
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An iterative time reversal high-power microwave approach to detect resonant frequencies of electronics
… simple scatterers despite ambient noise that was higher in power than the reflection of the DUT but was outside of the filtered frequency range. Three electrically complex DUTs were then measured in the GTEM and one in the semi-reverberant room. The results of the GTEM and semi-reverberant room …
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Advancing high power microwave spark-gap technology : design and analysis of a coaxial ringdown oscillator
High-power microwave (HPM) systems play a significant role in radiated Intentional Electromagnetic Interference (IEMI) technologies. Generating high peak voltages allows HPM systems to produce powerful electromagnetic pulses. However, their development is limited by challenges in achieving high …
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High-Power Microwave/ Radio-Frequency Components, Circuits, and Subsystems for Next-Generation Wireless Radio Front-Ends
… As the essential part of the hardware, power amplifiers (PAs) capable of operating over a wide bandwidth have been identified as the key enabling technology. This dissertation focuses on novel methodologies for designing and realizing broadband high-power PAs, their integration with …
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Design, fabrication, and characterization of indium phosphide-based heterostructure field-effect transistors for high-power microwave applications
… have, over the past several years, demonstrated microwave performance capabilities superior to those of GaAs-based and Si-based transistors. In particular, InGaAs/InAlAs modulation-doped field effect transistors (MODFETs) have exhibited world-record unity current gain frequencies ($f\sb{t}$s) as …
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Dielectric Properties of Minerals and Ores and the Application of Microwaves for Assisted Comminution and Ore Sorting
Upon exposure to microwave radiation, most valuable minerals heat very well, while in general, gangue minerals do not. This selective heating leads to differential thermal expansion across phase boundaries and causes microfractures, which can improve liberation and reduce ore competency. During ore …
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Design and simulation of a compact radiating system for high power microwaves in the 4 to 6 GHz range
As high power microwave technologies have advanced, demands have called for sources and radiators to become more compact. The University of Missouri has designed and simulated a compact radiating system for a compact virtual cathode oscillator. The radiating system has been developed to efficiently …
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Performance analysis of high power photoconductive switch at elevated temperature
This project deals with the analysis of high power radio frequency effects on a non-linear opposed contact GaAs photoconductive semiconductor switch, used in high power microwave generation. Specifically, effects of heating on the contacts and the bulk were studied. The changes in the I-V …
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Synthesis Technique of Thickness-Customizable Multilayered Frequency Selective Surface for Plasma-Based Electromagnetic Structures
… for the design of thickness-customizable high-order (N ≥ 2) bandpass frequency selective surface (FSS) and its application in realizing versatile multi-layered FSS and absorbers. Admittance inverters layers are used to synthesize the transfer response of the filter given desired …
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Dynamic nuclear polarization of biological systems at high magnetic fields
… nuclear polarization methods were studied at high magnetic field strength and were applied to improve the sensitivity of the nuclear magnetic resonance spectroscopy of biological solids. Studies of the dynamics of electron-nuclear polarization transfer via the solid effect and thermal mixing …
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Coherent Dynamic Nuclear Polarization: Mechanistic Insights and Experimental Advances
… the development of pulsed DNP—employing short, high-power microwave bursts—has shown the advantages of coherent spin control. We present both theoretical and experimental investigations aimed at understanding and optimizing polarization transfer. On the theoretical side, we examined multiple DNP …
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Design and implementation of a X-band transmitter and frequency distribution unit for a synthetic aperture radar
Synthetic aperture radar (SAR) can provide high-resolution images of extensive areas of the earth's surface from a platform operating at long ranges, despite adverse weather conditions or darkness. A local consortium was established to demonstrate a consolidated South African SAR ability to …
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