RF boards coating - RF Cafe Forums
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Below are all of the forum threads, including all
the responses to the original posts.
Post subject: RF boards coating Posted: Sun Feb 15, 2004 9:18 am
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.
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!!
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?
Post subject: Re: RF boards
coatingPosted: Fri Feb 20, 2004 5:08 pm
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
Welcome to Forum!
What is the applications for (be specific)? If
Satellite, LEO, MEO or GEO?
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?
Below is another one for your contact:
I hope this will help you. Good luck!
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.
Post subject: Posted: Tue Jun
08, 2004 2:34 am
why shouldn't the RF paths and microstrip lines be covered with solder mask?
The most important thing is don't cover the RF paths and microstrip lines with solder mask!!
Post subject: Posted: Tue Jun 08, 2004 10:53 am
Joined: Sun Aug 03, 2003 2:02 pm
Location: Erie, PA
why shouldn't the RF
paths and microstrip lines be covered with solder mask?
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.
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.
Post subject: Posted: Fri Jun 11, 2004 12:48 pm
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.
Post subject: about the bla bla blaPosted: Sat Aug 27, 2005 1:54 am
resonators and transmission lines with black mud. Does it work better?