16.360 Lecture 12

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16.360 Lecture 12
Last lecture

• impedance matching

A
Ii
Zg
Vg(t)
Matching network
ZL
Z0
Zin
Tarnsmission line
A
Zin Z0
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16.360 Lecture 12

• single-stub impedance matching network

d
M
A
Ii
Zg
Vg(t)
Yin
Y0
ZL
Yd
Transmission line
A
M
Ys
An example
l
A 50-? transmission line is connected to an
antenna with in a load ZL (25-j50)?. Find the
position and the length of the short-circuited
stub required to match the line.
Smith Chart
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16.360 Lecture 12
Today

• Transient on transmission line

A
Ii
Zg
Vg(t)
Z0
Tarnsmission line
If ?1, ?2,, ?n are transmitted on the
transmission line at the same time, each
frequency has its own location of voltage
distribution. The total voltage V(z) is the sum
of all these V?i(z).
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16.360 Lecture 12
Step function and pulse function

• step function U(t)

U(t) 1, if tgt0 U(t) 0, if tlt0

• single pulse function V(t)

V(t) U(t) U(t-t0),
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16.360 Lecture 12

• transient of a step function

A
Zg
Vg(t)
Ii
Z0
Tarnsmission line
-


?gV1
V2
V1
-
-


?gV1
V2
?LV2
?LV1




V
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16.360 Lecture 12
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16.360 Lecture 12

• Bounce Diagram

? ?g
? ?L
T
2T
3T
4T
5T
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16.360 Lecture 12

• An example

Z0 75?, ?r 2.1, Vg ?, Zlf ?, Lf ?
V
6V
3V
t
12?s
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