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RF boards coating - RF Cafe Forums
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Al
Post subject: RF boards coating Posted: Sun Feb 15, 2004 9:18
am
Hi:
We are developing some RF boards for space application.
As usual this boards must be protected by a coating, but the material
should not have any effect on the RF signal. Any advice or suggestion
of supplier?
Thanks a lot.
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Guest
Post
subject: Posted: Wed Feb 18, 2004 4:16 pm
The most important thing
is don't cover the RF paths and microstrip lines with solder mask!!
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JGP
Post subject: RF boards coatingPosted: Thu
Feb 19, 2004 8:58 pm
Welcome to Forum!
What is the applications
for (be specific)? If Satellite, LEO, MEO or GEO?
Sincerely,
John Pereira
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Al
Post subject: Re: RF boards
coatingPosted: Fri Feb 20, 2004 5:08 pm
Hi:
The application is
for a LEO satellite. We have experience working with Low Freq. Boards
in which there is not problem applying coating. Have you used Parylene
coating in RF boards?
Thanks.
JGP wrote:
Welcome to Forum!
What is the applications for (be specific)? If Satellite, LEO, MEO
or GEO?
Sincerely,
John Pereira
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JGP
Post subject: RF boards coatingPosted: Mon Feb 23, 2004 2:38 pm
No, I haven’t used their services. Why don’t you try them?
http://advancedcoating.com/coating.htm
Below is another one for your contact:
http://www.standardpc.com/profile.htm
I hope this will help you. Good luck!
Sincerely,
John
Pereira
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va3diw
Post subject: Posted: Wed
May 05, 2004 4:19 pm
hahaha. Gold is bad, solder mask is bad, special
paints are high loss/high permitivity. Seriously, go to the drugstore
across the street. I used the righ microwave nail polish for 20years
and it works. Wish somebody would told me.
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pigger
Post subject: Posted: Tue Jun 08, 2004 2:34 am
why shouldn't
the RF paths and microstrip lines be covered with solder mask?
Anonymous wrote:
The most important thing is don't cover the
RF paths and microstrip lines with solder mask!!
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Kirt Blattenberger
Post subject: Posted: Tue Jun 08, 2004 10:53
am
Site Admin
Joined: Sun Aug 03, 2003 2:02 pm
Posts: 308
Location: Erie, PA
pigger wrote:
why shouldn't
the RF paths and microstrip lines be covered with solder mask?
Greetings Pigger:
Solder mask is lossy (higher insertion
loss along the line), and unless the dielectric constant and thickness
of the mask layer is modeled properly in your simulator, the impedance
will be incorrect.
For relatively short runs and frequencies
under about 1 GHz, I have not had major problems with using solder mask,
though. Someone with more experience might want to offer an opinion
at higher frequencies.
- Kirt B.
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ck
Post subject: Past experience with coating.Posted: Fri Jun 11, 2004
11:45 am
Several years ago, the company I worked for sold a COTS
telemetry receiver for use on the International Space Station. There
was a need to coat all circuit boards. The receiver was P-band (under
500 MHz) as downconversion was done elsewhere. A unit earlier sold for
evaluation/vibration/rad approval for the project was reacquired, and
'converted' to prove out the process.
Surprisingly, no problems
were encountered. In fact, we found the noise figure of the receiver
dropped slightly after mods! Later flight units were modified with no
problems. For this project, a Humidseal product was approved and used.
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Itay
Post subject: Posted: Fri Jun 11, 2004
12:48 pm
At frequency under 1GHz the solder mask doesn't have any
effect. It starts to affect at frequencies above 3GHz. It increases
the insertion loss, there are types of solder mask which don't cause
this phenomena, they are more expensive though, and required for specific
applications.
Sensitive circuits such as distributed elements (filters,
couplers etc), shouldn't be covered with solder mask above these frequencies.
- Itay
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va3diw
Post subject: about the
bla bla blaPosted: Sat Aug 27, 2005 1:54 am
cover your resonators
and transmission lines with black mud. Does it work better?
Posted 11/12/2012
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