Sponsor
Portland State University. Department of Electrical and Computer Engineering
First Advisor
Lisa M. Zurk
Date of Publication
1-1-2010
Document Type
Dissertation
Degree Name
Doctor of Philosophy (Ph.D.) in Electrical and Computer Engineering
Department
Electrical and Computer Engineering
Language
English
Subjects
Electromagnetic waves -- Scattering, Electromagnetism, Finite differences, Time-domain analysis
DOI
10.15760/etd.865
Physical Description
1 online resource (xxii, 183 p.) : ill. (chiefly col.)
Abstract
Terahertz (THz) reflection and transmission spectroscopy is a promising new field with applications in imaging and illicit material detection. One particularly useful application is for the detection of improvised explosive devices (IEDs) which is a favorite weapon of global terrorists. Explosive materials have been shown to have a unique spectral signature in the THz band which can be used to identify the explosives. However, the initial measurements performed on the explosive samples do not account for the modulation of the spectral features by random scattering that will be prevalent with actual samples encountered in applications. The intent of this work is to characterize and quantify the effects of random scattering that may alter the spectral features. Specifically, the effect that a randomly rough surface and granular scattering has on the scattered THz wave (T-Rays) will be investigated and characterized using the Finite-Difference Time-Domain (FDTD) simulation method. The FDTD method is a natural choice for this work as it can handle complicated geometries (i.e., multiple scatterers, arbitrarily rough interfaces, etc.) arbitrary materials (i.e., dispersive media, etc.) and provides broadband frequency data with one simulation pass. First, the effect that the randomly rough surface of the sample explosive has on the extracted spectral signature will be studied using a Monte-Carlo analysis. Then the effect of the complex structure inside the explosive material (the granular scatterers) will be considered. Next, when the physics of the rough surface and granular scattering are understood, a robust method to extract the spectral signature from the reflected T-rays will be developed.
Rights
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Persistent Identifier
http://archives.pdx.edu/ds/psu/4863
Recommended Citation
Sundberg, Garth, "Numerical Modeling of Electromagnetic Scattering in Explosive Granular Media" (2010). Dissertations and Theses. Paper 865.
https://doi.org/10.15760/etd.865
Comments
Portland State University. Dept. of Electrical and Computer Engineering