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Electromagnetic Metamaterials
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Electromagnetic Metamaterials and their
Approximations:
Practical and Theoretical Aspects
CSIC Building (#406),
Seminar Room 4122.
Directions: home.cscamm.umd.edu/directions
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Near-cloaking by Change of Variables at Finite
Frequency II:
Numerical Assessment, Success, and Limitations
Professor
Daniel Onofrei
University of Utah
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Abstract:
This talk examines the performance of the
approximate cloaks introduced in part I. These
cloaks are obtained by applying the
change-of-variable scheme using
(i) a lossy layer surrounding a small ball, and
(ii) a nonsingular change of variable that "blows
up" the small ball to the region being cloaked.
Since the goal is to make the cloaked region
invisible, it is not sufficient to test the
visibility of a generic object in the cloaked
region. Rather, it is important to consider
worst-case examples. For cloaks with spherical
symmetry, we show how such examples can be
identified using separation of variables. Using
these worst-case examples, we explore the quality of
the approximate cloaks discussed in part I. In
particular, we explore the importance of using a
lossy layer at the inner edge of the cloak. Our
results suggest that use of a lossy layer is
crucial, if cloaking is to be achieved without
regard to the dielectric properties of the object
being cloaked. |
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