Electrical and Computer Engineering ETDs

Publication Date

1-28-2015

Abstract

High-power microwave research strives for compact and highly efficient vacuum diode-driven sources. MAGIC particle-in-cell (PIC) computer simulations have shown that the performance of the well-known A6 relativistic magnetron with radial power extraction through one or more of its cavities can be improved by instead using axial power extraction through a mode-converting horn antenna, resulting in improved efficiency (30% improved to 70%) and greater output power handling capability (sub-gigawatt improved to multi-gigawatt) without breakdown. In addition, axial extraction results in a more compact profile that is compatible with mounting permanent magnets, which eliminate the need for bulky pulsed electromagnets or cryo-magnets and greatly enhance system efficiency. To this end, a variety of technologies were simulated and tested in experiment, the latter which required the design, construction, testing, and calibration of new diagnostics, pulsed power systems, and hardware, such as the complex A6 magnetron with diffraction output horn antenna (MDO). The primary goal of the experiments was to verify simulated 70% efficiency and greater than 1 GW of output power from the MDO. A less expensive vii compact MDO' variant, essentially an A6 magnetron with a flat-plate mode converter and \u03c0-mode strap was also simulated. Although both the MDO and the compact MDO are compatible with permanent magnets fitted around their exteriors, an effective configuration was simulated for the compact MDO, promising reduced size and increased efficiency of the total microwave system. In addition, both versions of the MDO were susceptible to bombardment of leakage electrons on their output windows; cathode endcaps were developed and tested to mitigate this issue. Finally, to further improve output power, a rodded metamaterial-like cathode that showed improved power in other relativistic magnetrons was also considered by simulation in an A6 magnetron with radial extraction.'

Keywords

axial extraction, magnetron, MDO, high power microwave, A6, compact

Sponsors

Office of Naval Research Grant N00014-13-1-0565, Air Force Office of Scientific Research Grant FA9550-11-1-0200, Air Force Office of Scientific Research DURIP Grant AF2386-12-13027, Raytheon University Research Project #2012-UNI-00022

Document Type

Dissertation

Language

English

Degree Name

Electrical Engineering

Level of Degree

Doctoral

Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Gilmore, Mark

Second Committee Member

Christodoulou, Christos

Third Committee Member

Cooper, Gary

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