CERAMIC COAXIAL RESONATORS
Application notes
APPLICATION NOTES
S OLDERING RECOMMENDATIONS
Before any soldering operation is im plem ented, the coaxial resonator m ust be preheated in order
to avoid a therm al shock and a subsequent m echanical stress liable to initiate failure m echanism .
TEMEX recom m ends a m inim um preheating tim e of 2 m inutes at 120° C with a m axim um heating rate
of 2° C / sec.
FREQUENCY ADJ USTMENT
When the frequency tuning adjustm ent is needed, two solutions can be adopted:
a)
Mechanical lapping of the ceram ic, or m echanical grinding of m etallization, depending where
m etallization will be grinded off.
b) Using a TEMEX air or sapphire dielectric tuning capacitor (“Air trim m er” or“Gigatrim ”):
in this case, the frequency will decrease when capacitance will increase.
This provides an additional advantage of m ounting / term inating resonator to the assem bly
by utilizing the leg configuration of the tuning capacitor.
QUALITY FACTOR Q
The Q factor of a coaxial resonator is essentially determ ined by the m etallization.
The dielectric m aterial, 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 m in. increases as frequency increases (proportionally to Fo).
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