In an electromagnetic cloak based on a transformation approach, reduced sets of
material properties are generally favored due to their easier implementation in reality,
although a seemingly inevitable drawback of undesired reflection exists in such cloaks.
Here we suggest using high-order transformations to create smooth moduli at the outer
boundary of the cloak, therefore completely eliminating the detrimental scattering
within the limit of geometric optics. We apply this scheme to a non-magnetic
cylindrical cloak and demonstrate that the scattered field is reduced substantially in a
cloak with optimal quadratic transformation as compared to its linear counterpart.
We obtained the energy transport velocity distribution for a three dimensional ideal cloak
explicitly. Near the operation frequency, the energy transport velocity has rather peculiar
distribution. The velocity along a line joining the origin of the cloak is a constant, while
the velocity approaches zero at the inner boundary of the cloak. A ray pointing right into
the origin of the cloak will experience abrupt changes of velocities when it impinges on the
inner surface of the cloak. This peculiar distribution causes long time delays for beams
passing through the ideal cloak within a geometric optics description.
This book describes the applications of the fundamental interactions of
electromagnetic waves and materials as described in the preceding volume, “Basic
Electromagnetism and Materials”. It is addressed to students studying masters or
doctorate courses in electronics, electromagnetism, applied physics, materials
physics, or chemical physics. In particular, this volume analyzes the behavior of
materials in the presence of an electromagnetic field and related applications in the
fields of electronics, optics, and materials physics.
Free Space Optical Communication (FSOC) is an effective alternative technology to
meet the Next Generation Network (NGN) demands as well as highly secured (mili-
tary) communications. FSOC includes various advantages like last mile access, easy
installation, free of Electro Magnetic Interference (EMI)/Electro Magnetic Compatibil-
ity (EMC) and license free access etc. In FSOC, the optical beam propagation in the
turbulentatmosphereisseverelyaffectedbyvariousfactorssuspendedinthechannel,
geographicallocationoftheinstallationsite,terraintypeandmeteorologicalchanges.
Therefore a rigorous experimental study over a longer period becomes significant to
analyze the quality and reliability of the FSOC channel and the maximum data rate
that the system can operate since data transmission is completely season dependent.
The field of digital communication has evolved rapidly in the past few
decades, with commercial applications proliferating in wireline communi-
cation networks (e.g., digital subscriber loop, cable, fiber optics), wireless
communication (e.g., cell phones and wireless local area networks), and stor-
age media (e.g., compact discs, hard drives). The typical undergraduate and
graduate student is drawn to the field because of these applications, but is
often intimidated by the mathematical background necessary to understand
communication theory.
The use of optical free-space emissions to provide indoor wireless commu-
nications has been studied extensively since the pioneering work of Gfeller
and Bapst in 1979 [1]. These studies have been invariably interdisciplinary in-
volving such far flung areas such as optics design? indoor propagation studies?
electronics design? communications systems design among others. The focus
of this text is on the design of communications systems for indoor wireless
optical channels. Signalling techniques developed for wired fibre optic net-
works are seldom efficient since they do not consider the bandwidth restricted
nature of the wireless optical channel.
Static electricity is the most ancient form of electricity known to humans. More
than 2000 years ago, the Greeks recognized the attraction between certain mate-
rials when they were rubbed together; indeed, the word electricity comes from
the Greek elektron, which means amber. During the seventeenth and eighteenth
centuries, several key experiments were conducted to understand and measure
static electricity. But the discovery of electromagnetism and its formidable break-
through has rapidly outgrown interest in static electricity. Even today, where
the industrial applications of static electricity are not insignificant, they cannot
compare with those of electromagnetism and electrodynamics.
The challenges associated with the design and implementation of Electro-
static Discharge (ESD) protection circuits become increasingly complex as
technology is scaled well into nano-metric regime. One must understand the
behavior of semiconductor devices under very high current densities, high
temperature transients in order to surmount the nano-meter ESD challenge.
As a consequence, the quest for suitable ESD solution in a given technology
must start from the device level. Traditional approaches of ESD design may
not be adequate as the ESD damages occur at successively lower voltages in
nano-metric dimensions.
