1. ELECTRONIC MATERIALS, SENSORS, STRUCTURES
AND ENERGY TRANSFER
CARLOS M. PEREIRA PH.D.
Waves transport energy as a periodic disturbance through a medium from one
particle to adjacent particles depending on the type of waves. Waves exist in
different types and forms, but they all have some basic common characteristics
and behaviors. Observable waves required certain medium characteristics in
order to transport energy from one location to another, sound waves transmit
particles of air vibrating back and forth as the energy transport mechanism.
Observable waves can also travel through a solid medium or through a medium
such as a liquid or a gas, however, observable waves cannot travel through
vacuum or free-space. Other categories of waves that can travel through vacuum
or free space are characterized as non-observable waves and are associated
with electromagnetism principles and known as electromagnetic waves. These
types of waves can travel in vacuum or free-space where medium materials do
not exist, however, electromagnetic waves also propagate in material mediums
where forms of polarizable dielectrics, magnetizable materials and other
conductive materials that may have low mobilities would provide propagation
mediums with imperfect conduction. Propagation of electromagnetic waves in
both vacuum or in situations where dielectric medium materials are present,
require two vectors that are time-dependent and that are closely interrelated.
One of these vectors is the electric field component the other vector is the
magnetic field component these two vectors are always perpendicular to each
other. The electric field and magnetic field vectors are also time inter-dependent,

2. exist in a three dimensional space region and may exist and propagate energy in
the absence of a medium.
Energy is transmitted by electromagnetic waves and can be transferred to a
surface or geometry relatively fast because the slowest possible interaction is
between kinetic energy and potential energy which is characteristic of
mechanical waves. When an electromagnetic wave interacts with a surface,
resonance occurs after a few cycles, as the propagated electromagnetic energy
interacts with the atoms of the surface. At the point of interaction, the energy
carried by the electromagnetic waves excites the mass of the electrons on the
interface material of the surface. These interactions cause charges distributions
on the surface with similar time varying characteristics which should achieve
resonance in a few cycles. Since these interactions would occur at high
frequencies at which the wave is being propagated, the transfer of the energy
from the propagated wave to the surface or geometry would occur very fast, as
an example, at a propagating frequency of ten Gigahertz, the transfer of energy
would occur in less than ten cycles, which would occur in a few nanoseconds.
The transfer of the information contained in the propagating wave should be
practically transferred to the surface instantaneously.
Electromagnetic waves travelling in vacuum or free-space propagate at a speed
which is a function of the free space capacitance or permittivity and the free
space inductivity or permeability . The wave travels at the measured quantity
of one over the square root of the capacitance of free space multiplied by the
inductivity of free space, and the result of this calculation is the speed of light .
Electromagnetic waves can propagate and transfer energy in a vacuum by
means of two orthogonal vectors, the electric field and the magnetic field vectors
which are interrelated in time and space and can be expressed as an integral
over the spatial region that encloses their sources, also represented as a set of
four differential equations known as Maxwell’s equations.
At the interface region of a propagating electromagnetic wave with a surface, the
amount of energy transferred to the surface will largely depend on the shape of
(ε0)
(µ0)
(c)

3. the surface and the type of material that composes the surface. As an example, if
a surface is a three dimensional object, the energy transferred to the object
largely depends on the materials of the surfaces and the amount of energy
carried by the propagated wave. At the point of interaction with an object, the
energy carried on the propagated wave produces a small current, which serves
as a source charge and at the point of interface the propagated wave produces a
localized vector field which depending on the material characteristics would then
be absorbed by the material or scattered. In the interaction of electromagnetic
waves with objects and its surfaces, electric fields are generated by electric
charges (current) and magnetic fields are generated by charge motion.
At the interface where the propagated wave interacts with the material medium,
energy is transferred to the surface which can absorb the incident energy or the
surface can reflect or scatter the energy in various directions. The resulting
propagation of electromagnetic waves very much depends on the medium of
propagation and the medium of propagation very much depends on its
constituting matter. Matter is classified according to the values of its capacitance
, its inductivity and the medium conductivity . In material mediums
with very high conductivities, there are many free carriers or particles (free
electrons) to absorb the energy of a propagating electromagnetic wave. In a
perfect conductive environment, the conductivity parameter approaches
infinity and all propagated energy that reaches a surface with very high
conductivities will be absorbed and distributed over the surface. Material
conductive properties may also have no conductive properties (no free carriers),
in which case the conductivity parameter would approach zero. These
parameters together with the surface geometrical shape have a high degree of
affect on the resulting interaction of a propagated electromagnetic wave at the
interface region location .
(ε) (µ) (σ )
(σ )
(σ )