Page 130 - Complete Wireless Design

Amplifier Design

Amplifier Design 129

matching capacitor X is now in parallel with the source’s resistance, instead
P
of the load’s resistance).
When two different, but pure, resistances must be matched, the above tech-
nique is easily and rapidly applied to perform this task. However, if reactances
must also be canceled within one or both of these circuits—as well as the resis-
tances matched—then one (or both) of the two following methods may be
employed.
Absorption uses the reactances of the impedance matching network itself to
absorb the undesired load and/or source reactances (Fig. 3.27). This is accom-
plished by positioning the matching inductor in series with any load or source
inductive reactance. In this way, the load or source’s X actually becomes part
L

Figure 3.26 The final L network component values for a matched
source and load.

Figure 3.27 Circuit that requires the addition of components to absorb reactances.

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