Masters Theses

Date of Award

8-1995

Degree Type

Thesis

Degree Name

Master of Science

Major

Electrical Engineering

Major Professor

Igor Alexeff

Committee Members

Marshall Pace, David Rosenberg

Abstract

We have successfully constructed a microwave plasma closing switch and a stealth plasma antenna using ordinary fluorescent tubes. For the microwave plasma closing switch, the basic idea is a coaxial plasma line structure the inner conductor of which is a fluorescent tube while the outer conductor is a metal pipe. Under normal conditions when the gas is not ionized, the system is just a waveguide beyond cutoff and microwave transmission is negligible. However, when the gas is ionized, the structure acts as an excellent coaxial line that transmits microwave. We have obtained a 63 dB relative amplitude for a 15 MHz signal and a 21 dB relative amplitude for a 900 MHz signal. By using a simple equivalent electrical circuit, we are able to predict the behavior of the coaxial line structure successfully. For the stealth antenna, the basic principle is based on the electromagnetic wave propagating in a plasma medium. If the incident wave frequency is greater the wave will propagate through the tube If the incident wave frequency is less than the plasma frequency, reflection will take place. However, when the gas is de-ionized, the radar cross section is negligible, rendering the antenna a stealth property. Our experimental work has successfully demonstrated the case.

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