Department of Electrical and
Computer Engineering
ECSE 352 Electromagnetic Waves and Optics
2 Wave propagation in dielectrics
2.2 Wave propagation in dielectrics
References: Section 12.2
2.21
Overview
So far we have looked at waves propagating in a vacuum, which is an ideal,
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edia
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lossless medium. All real media are lossy (to a certain degree) and we need to
understand how to calculate wave propagation in these. We will see that we can
divide materials into lossy conductors and low loss dielectrics. In a conductor the
dominant source of loss is electron conduction, whereas in a dielectric loss arises
due to damping of theelectric dipoles. Thiswill give us two different regimes of
calculation. In all cases however, loss can be represented by adding an imaginary
term to the dielectric constant. This results in an attenuation constant which causes
the electric field amplitude to decay exponentially with distance. We will see that
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y
py
loss is also frequency dependent and we will examine the impact of loss on choice
of EM wave frequency in various applications.
©AGK 2006
ECSE 352 2.22
Module 2: The Uniform Plane Wave
Module 1: Transmission Lines
Module 2: The Uniform Plane Wave
ave propagation in free space
1. Wave propagation in free space
2. Wave propagation in dielectrics
3. The loss tangent
4. Wave power and the Poynting vector
5. The skin effect
ave polarization
6. Wave polarization
Module 3: Waves at boundaries
©AGK 2006
ECSE 352 2.23
Module 4: Waveguides and antennas
Learning outcomes
After taking this class you should be able to:
• Model wave propagation in a lossy dielectric using
the
complex permittivity
model
alculate the properties of lossless dielectrics
•
Calculate the properties of lossless dielectrics
• Define the
refractive index
of a dielectric
• Model wave propagation in lossy materials
ppg
y
• Recognize that loss introduces
frequency
dependence
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 Spring '10
 mi
 Permittivity, Wave propagation, ECSE

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