Page 32 - Complete Wireless Design
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Wireless Essentials
Wireless Essentials 31
Figure 1.38 (a) A distributed capacitor; (b) two shunts equaling the single capacitor; (c)
equivalent lumped shunt capacitor.
Third, calculate the required microstrip’s length to become a capacitor of
value X , as calculated above, with this formula:
c
Arctan
30
X
c
length
360
where X capacitive reactance required in the distributed circuit, ohms
c
length length of the microstrip required to imitate a lumped
component of value X in mils (which should never be longer
c
than 30 degrees, or 12 percent, of )
wavelength of the frequency of interest for the substrate of
interest (or V ; see above formulas) , mils
P
Series inductor. As shown in Fig. 1.39, the equivalent series inductor is placed
in series with the 50-ohm microstrip transmission line, or placed between other
distributed or lumped components.
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