CERAMIC COAXIAL RESONATORS
Application notes
APPLICATION NOTES
SOLDERING RECOMMENDATIONS
Before any soldering operation is implemented, the coaxial resonator must be preheated in order
to avoid a thermal shock and a subsequent mechanical stress liable to initiate failure mechanism.
TEMEX recommends a minimum preheating time of 2 minutes at 120° C with a maximum heating rate
of 2° C / sec.
FREQUENCY ADJUSTMENT
When the frequency tuning adjustment is needed, two solutions can be adopted:
a)
Mechanical lapping of the ceramic, or mechanical grinding of metallization, depending where
metallization will be grinded off.
Using a TEMEX air or sapphire dielectric tuning capacitor (“Air
or“Gigatrim”):
in this case, the frequency will decrease when capacitance will increase.
This provides an additional advantage of mounting / terminating resonator to the assembly
by utilizing the leg configuration of the tuning capacitor.
b)
QUALITY FACTOR Q
The Q factor of a coaxial resonator is essentially determined by the metallization.
The dielectric material, having low losses, does not have a direct effect on the “Q” (secondary
influence).
The curves show the range of “Q” factor versus resonator size and frequency range.
Curves show that Q min. increases as frequency increases (proportionally to
√
Fo
).
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