CHAPTER 3
3.1. An empty metal paint can is placed on a marble table, the lid is removed, and both parts are
discharged (honorably) by touching them to ground. An insulating nylon thread is glued to
th
Notes 9
Polarization
According to the IEEE Standard Definitions for antennas the polarization of a radiated wave is
defined as That property of a radiated electromagnetic wave describing the time-vary
Notes 6
Conservation of Power and the Poynting Vector
Note the following:
) (
(
) (
)
1 1 1
A A = A A + A A = 2A A = A A
2
2
t
t
t
t
t 2
Recalling the first two of Maxwells equations we can manipula
Notes 11
Power Considerations
As a notational convenience we will represent the magnitude of the time-averaged Poynting vector
as P instead of S and call it simply the power density of the wave.
The p
Notes 14
Transmission Lines
Comparing the general form of the uniform plane waves electric field that we have been using, i.e.,
E = E 0 cos(t kz + ) with the form of the voltage that was used in study
Notes 10
Plane Waves at Boundaries
In the previous material we discovered that when incident upon a good conductor the electric and
magnetic fields of an EM wave attenuate very quickly at the boundary
Notes_1.doc
Scalar Fields and Vector Fields
A voltage as a function of time may be written as v (t ). This is an example of a function of one
variable. In electromagnetics this, as well as other quant
Notes 4
Development of Maxwells equations:
Faradays law of induction
r
(
s A ) dS = A d l
r
Recall Stokes theorem:
r
r
r
r
Since Stokes theorem is valid for any vector field, we can substitute the ele
Notes 3
Faradays Law of Induction and the Electromotive Force
Early in the history of the scientific examination of electromagnetism it was noted experimentally that
a voltage can be induced in a loop
Notes 5
The Uniform Plane Wave
Electromagnetic wave propagation
Maxwells equations show us that in a source-free region of free space ( = 0, J c = 0 ) a time-varying
magnetic field results in a non-ze
Notes 17
Impedance matching networks:
Weve determined that a load is said to be matched to its transmission line when the input impedance
Zin is equal to the characteristic impedance of the line, Z in
Notes 18
Example:
I. Let us assume that an antenna is feeding a television at a frequency of 6 MHz where we consider
the antenna to be the source for the television, which we will consider the load. C
Notes 8
We see that in high-loss media, i.e. when tan > 100 , we approximate the angle on the intrinsic
impedance as 45 !
Lets see how well that approximation works 1:
Take care not to confuse the two
Notes 13
Example: An EM wave with circular, right-hand polarization is normally incident from air onto a semiinfinite slab of plexiglass ( r = 3.45, eff = 0 ) . Calculate the percentages of the incide
Notes 7
Wave Propagation in Dielectric Media
Dielectrics differ from conductors in that they have few (if any) free charges available for conduction.
They do, however, have fixed, or bound, charges th
Quiz 2 - Basic Equations of Electrodynamics
Mathematical Identities
v(t) = Recfw_Vejtwhere V = |V|ej
= x /x + y /y + z /z
Electromagnetic Variables
E = electric field (V/m)
H = magnetic field (A/m)
A
Flux
open surface magnetic flux:
closed surface magnetic flux:
open surface electric flux:
closed surface electric flux:
del operator in Cartesian form
=
(Webers, Wb)
= 0 (always)
=
=
(Coul
The Chronology of Electromagnetics
~900 BC: Certain rocks (later called magnetite) were found to attract iron bits and bits of
straw.
~600 BC: Greek philosopher Thales described how amber, after being
Final Exam - Basic Equations of Electrodynamics
Mathematical Identities
v(t) = Recfw_Vejtwhere V = |V|ej
= x /x + y /y + z /z
Electromagnetic Variables
E = electric field (V/m)
H = magnetic field (A/
EE 3320 Homework
Name: _
Be sure to write the standard form for the E-field and clearly identify A and .
1. Utilize the polarization chart below to ascertain the polarization classification of the fol
38
2
Uniform Plane Waves
2. Uniform Plane Waves
Because also z Ez = 0, it follows that Ez must be a constant, independent of z, t.
Excluding static solutions, we may take this constant to be zero. Sim
Notes 16
Smith Chart
The Smith chart is the most widely used graphical technique for analyzing transmission line circuits
and designing impedance matching circuits. Today much is computerized, however
Notes 12
Plane wave propagation in general directions
Previously weve described the electric field via E y = E y0 e jkz (for example). Technically, we could
jk r
jk z z
jk r
have written E y = E
Notes 15
Three limiting cases to note about L :
Short circuit the load: Z L = 0
L = 1
Open circuit the load: Z L
L = +1
Matched line ( Z L = Z o )
So there is no reflection.
L = 0 V = 0
We see that w