5.3 Amplifier Design Stages
215
Yet again, we may want to apply some selective mismatch to achieve a specific value of gain. Our
output matching network can therefore also be seen as a gain dial which provides a gain
|
|
| |
whose maximum value is achieved when i.e.
when a conjugate match is achieved at the
output.
The complete picture is shown in Figure 5.3-9.
Figure 5.3-9 Gain tuning by means of input and output matching networks with unilateral device
The expression for the overall unilateral gain is shown below
|
|
|
|
|
|
|
|
| |
And
the maximum value for the unilateral matching gain is
Our
unilateral matching video tutorial (video 5.5) will give the reader a greater insight into this
technique and its limitations.
Note that the gain is often expressed in dB. In this case eq. (5.3-1) becomes
G
0
Transistor
+
Bias
Z
0
Z
0
S
12
S
21
S
11
S
22
Input
matching
network
G
S
Output
matching
network
S L
G
0
G
S
G
L
(5.3-1)
Conquer Radio Frequency
215 www.cadence.com/go/awr
