EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: Alexei.Polkhanov on August 29, 2014, 12:54:44 am
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What should I use to glue Dielectric Resonators to PCB? I was Googling around and cannot find definitive answer on how Dielectric Resonators can be attached to the PCB.
Can I use SuperGlue?
If I need to use spacer what material spacer should be made from?
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What should I use to glue Dielectric Resonators to PCB? I was Googling around and cannot find definitive answer on how Dielectric Resonators can be attached to the PCB.
Can I use SuperGlue?
If I need to use spacer what material spacer should be made from?
Hmm. It seems odd that in datasheets like this http://www.temex-ceramics.com/site/fichiers/dielectric.pdf (http://www.temex-ceramics.com/site/fichiers/dielectric.pdf)
they don't say anything about what glue to use.
Have you tried just asking a supplier?
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I got few pretty good resonators but supplier barely knows what they are selling. It appears that my Googgling finally led me to some suppliers of what they call "low loss glue"
(this one for example: http://www.eccosorb.com/products-eccostock-low-loss-dielectrics.htm (http://www.eccosorb.com/products-eccostock-low-loss-dielectrics.htm)). They sell it in big quantities of course.
Answering my second question regarding superglue - it was simple really. I feel stupid I did not check it immediately. Dielectric constants of most glues have been measured and it happens that it is easy to find this data on internet! I found those parameters for superglue and it appears that it has dielectric constant (permittivity) of 3.3 and loss tangent 0.06 at 10MHz. PTFE in comparison is 2.1 with 0.00028 loss and FR4 is 4.8 and 0.008 loss so it is pretty bad for superglue - looks like it is not very good choice. Other sources actually suggest cyanoacrylic which is a SuperGlue so I am little bit confused. :-\
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You use only a small drop in the middle of the bottom of the resonator, so it will not add much loss to the circuit. Slathering it in glue is not really going to work. you might also try silver loaded epoxy or windscreen demister repair paint as it is conductive so low loss.
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Hmmm, conductive glue for dielectric resonator? I am not sure if that is a good idea. Do you have any references?
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I assume this is going on a high performance PCB material? I'd try to find out what the epoxy used in the PCB.
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It is Rogers RO3010, I don't think there is any epoxy in it.
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Hmm. Megtron 6 uses "ppe blend resin", whatever that is, and that led me to
"Plastics for Electronics"
http://books.google.ca/books?id=v_FCFUEXsbMC&lpg=PA55&ots=7cqm5nD-i-&dq=ppe%20blend%20resin%20system&pg=PP1#v=onepage&q=ppe%20blend%20resin%20system&f=false (http://books.google.ca/books?id=v_FCFUEXsbMC&lpg=PA55&ots=7cqm5nD-i-&dq=ppe%20blend%20resin%20system&pg=PP1#v=onepage&q=ppe%20blend%20resin%20system&f=false)
Me, I'd just JB Weld the thing and see what happens...
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I have repaired LNB units before where the resonator fell off the board, and a small drop of superglue worked well. Place on the middle of the old one with a pin tip and then place the DRO back on top and leave to cure. Put cover back on and stick back up on the roof and it worked till the dish rusted off. That was when the dish cost a lot, and the LNB was the cost of the digital converter box. Now you buy the whole kit for $50 including installation.