GW Instek GRF-3300 Series Student Manual - Manual (Page 6)

GRF-3300 Manual
3 314
O L
O L
o
o
Z Z
Z Z
V
V
*
(16-12)
When load mismatch occurs, not all generated power is delivered to the
load. This “loss” is called Return Loss (RL), and is defined (in dB) as
*
log 20 RL dB (16-13)
*
*
1
1
min
max
V
V
SWR (16-14)
The general form of the input impedance in Figure 16-3 is described as follows.
l j
O L
l j
O L
l j
O L
l j
O L
O in
e Z Z e Z Z
e Z Z e Z Z
Z Z
E E
E E
) ( ) (
) ( ) (
l jZ l Z
l jZ l Z
Z
L O
O L
O E E
E E
sin cos
sin cos
l jZ Z
l jZ Z
Z
L O
O L
O E
E
tan
tan
(16-15)
16-1-4. Special Cases of Terminated Lossless Lines
When a line is terminated in a short circuit, Z
L
becomes Z
L
=0. From 16-15 Zin is:
l jZ Z
O in
E
tan (16-16)
When a line is terminated in an open circuit, from 16-15 Zin is:
l jZ Z
O in
E
cot (16-17)
When the line length is
O/2:
L in
Z Z (16-18)
When the line length is
O/4: