Page 136 - Complete Wireless Design

Amplifier Design

Amplifier Design 135

Figure 3.35 Reactance values as calculated for pi network.

easier to absorb any reactances. These conversion equations are found later
in this chapter.
1. Select a proper network topology that will absorb both stages’ reactances.
In this case, we would choose a pi network with two parallel capacitors (see
discussion above on absorption).
2. Choose a desired Q and frequency of operation.
3. Find “R,” the virtual resistance:

R
H
"R"
2
Q 1
Note: R is equal to whichever source or load resistance is larger, R or R .
H L S
4. Find X and X by:
C2 L2

R
L
X and X Q"R"
C2 Q L2
for the load-side values.
5. Find X and X by:
C1 L1

R R
S
S

1
X |Q and X Q "R"
C1 Q 1 "R" L1 1
1
6. As shown in Fig. 3.38, add X and X to form X ; combine X and
L1 L2 LNEW CSTRAY1
X ; then combine X and X (X and X must be smaller than
C1 CSTRAY2 C2 C1 C2
X and X respectively, since adding two capacitors’ reactances in
CSTRAY1 CSTRAY2
parallel involves:
X C
STRAY
C
X
X C C
C STRAY
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