Notes 11 Fall 2004.doc
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 timevarying direction
and relative magnitude of the electric field vector; specifically, the figure traced as a function of
time by the extremity of the vector at a fixed location in space, and the sense in which it is traced, as
observed along the direction of propagation.”
We showed before for the field represented in free space by
(
)(
z
k
t
cos
E
x
ˆ
t
,
z
0
0
x
−
ω
)
=
E
G
that at a
particular choice of z the electric field vector varies in a straight line.
Therefore, we can say that
this electric field is a linearly polarized
uniform plane wave.
In phasor form this field is
.
z
jk
0
x
s
0
e
E
x
ˆ
E
−
=
G
We can write a more general phasor form which will encompass two additional polarization types:
()
(
b
0
a
0
z
k
j
z
k
j
s
be
y
ˆ
ae
x
ˆ
E
φ
+
±
φ
+
±
+
=
)
G
where a and b are the amplitudes for each direction and
a
φ
,
b
φ
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 Fall '10
 Czarnecki
 Polarization, Electromagnet, φ, Circular polarization, 2 radians

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