Electrical and Computer Engineering ETDs

Publication Date

Spring 4-12-2018

Abstract

Experimental Testing of a Metamaterial Slow Wave Structure for High-Power Microwave Generation

by

Kevin Aaron Shipman

B.S., Exercise Science, University of New Mexico, 2008

A.S., Mathematics, San Juan College, 2014

M.S., Electrical Engineering, University of New Mexico, 2018

Abstract

A high-power L-band microwave source has been developed using a metamaterial (MTM) to produce a biperiodic double negative slow wave structure (SWS) for interaction with an electron beam. The beam is generated by a ~700 kV, ~6 kA short pulse (~ 10 ns) electron beam accelerator. The design of the metamaterial SWS (MSWS) consists of a cylindrical waveguide, loaded with alternating split-rings that are linearly arrayed axially down the waveguide. The beam is guided down the center of the rings by a strong axial magnetic field. The electrons interact with the MSWS producing electromagnetic radiation in the form of high-power microwaves (HPM). The Power is extracted axially by a conical horn antenna.

Microwave generation is characterized by an external cutoff waveguide detector, as well as the radiation pattern of the RF. Mode characterization is performed using a neon bulb array, where the bulbs are lit by the electric field in such a way that the pattern in which they are excited resembles the field pattern. A time integrated image is of this pattern is taken by an SLR camera. Since the MTM structure has electrically small features, breakdown within the device is a concern. Therefore, a fiber-optic-fed, sub-ns photomultiplier tube array diagnostic has been developed and used to characterize light emission from breakdown. A description of the diagnostic developed and experimental results will be presented.

Keywords

High-power microwaves, slow wave structure, metamaterials, backward wave oscillators, electrical breakdown, mode characterization

Sponsors

AFOSR MURI Grant FA9550-12-1-0489

Document Type

Thesis

Language

English

Degree Name

Electrical Engineering

Level of Degree

Masters

Department Name

Electrical and Computer Engineering

First Committee Member (Chair)

Dr. Mark Gilmore

Second Committee Member

Dr. Edl Schamiloglu

Third Committee Member

Dr. Dustin Fisher

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