- Link:
- http://hdl.handle.net/1721.1/16615
- Collection:
-
- Subjects
- Electrical Engineering and Computer Science. Electrical Engineering and Computer
Science.
- Creator:
- Pacheco, Joe, 1978-
- Contributors:
- Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. Jin A. Kong. Massachusetts Institute of Technology. Dept. of
Electrical Engineering and Computer Science.
- Format
- 235 p.
- Format
- 6334649 bytes
- Format
- 7475899 bytes
- Format
- application/pdf
- Language
- eng
- Publisher
- Massachusetts Institute of Technology
- Rights
- M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See
provided URL for inquiries about permission.
- Rights
- http://dspace.mit.edu/handle/1721.1/7582
- Type
- Thesis
- Description
- Materials with simultaneously negative permittivity
and permeability over a certain frequency band were first studied
by Veselago in 1968, who termed such media left-handed (LH) due to
the LH triad formed by the electric field vector, the magnetic
field vector, and the phase propagation vector. However, since no
such naturally occurring materials were known, Veselago's work laid
dormant for nearly 30 years. Recently though, a composite material,
also known as a metamaterial, consisting of the periodic
arrangement of metallic rods and split-rings has been shown to
exhibit left-handed properties. Because the dimension of the rods
and rings that makeup the metamaterial are small compared to the
wavelength of interest, it is possible to approximately describe
their bulk electromagnetic properties using an effective
permittivity and an effective permeability. In this thesis, the
properties and potential applications of LH media are explored. In
addition, various tools are presented for the purpose of
characterizing metamaterial designs. Before studying their
metamaterial realization, the basic properties of propagation,
radiation, and scattering through homogeneous LH media are studied.
Many of the basic properties of LH media are in contrast to those
typically encountered in right-handed media. For example, using a
rigorous plane wave analysis of propagation and transmission into a
dispersive LH medium from a RH medium, it is shown that power
refracts at a negative angle, without violating causality. Second,
the perfect lens concept is studied through a Green's function
analysis. It is shown that under the perfect lens requirement, that
a single source outside a LH media slab will generate two perfect
images.
- Description
- (cont.) Interestingly though, the time-averaged
power flow inside the slab forms a sink. However, it is shown that
while the introduction of loss eliminates this behavior, the lens
becomes imperfect. It is seen that even a small amount of loss can
destroy the imaging properties of the LH media lens. In terms of
scattering, the Mie solution for plane wave scattering by a LH
medium sphere is examined. It is shown that where applicable, care
must be taken in choosing the appropriate algebraic signs of the
wavenumbers in the evaluation of the Mie coefficients. In addition,
it is then shown that a sphere composed of a LH medium will focus
incoming energy into a spot inside the sphere. Finally, because the
metamaterials studied in this thesis are anisostropic, the effects
of aniostropy on reflection and transmission are examined. Next,
various tools for understanding and characterizing left-handed
metamaterials are presented. First, the accuracy of approximate
analytic models of the rods and split-rings is investigated by
using two-dimensional FD-TD simulations to compare transmission
characteristics. It is shown that the rods tend to agree more
favorably with their analytic model than the split-rings do. Next,
in order to better understand the behavior of the rods and rings
separately, numerical simulations of rods (or rings) embedded in
homogeneous mag- netic (or electric) plasma media were performed.
Using the transmission characteristics, it is shown that in order
to obtained left-handed features, the plasma in the immediate
vicinity of the rods or rings needed to be removed,
...
- Description
- by Joe Pacheco, Jr.
- Description
- Thesis (Ph. D.)--Massachusetts Institute of
Technology, Dept. of Electrical Engineering and Computer Science,
2004.
- Description
- Vita.
- Description
- Includes bibliographical references (p.
223-244).
- Description
- This electronic version was submitted by the
student author. The certified thesis is available in the Institute
Archives and Special Collections.
- Rights
- M.I.T. theses are protected by copyright. They may be
viewed from this source for any purpose, but reproduction or
distribution in any format is prohibited without written
permission. See provided URL for inquiries about
permission.
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