Keep in mind that soldermask will also change the field distributions
around a
microstrip line, and will somewhat mitigate the microstrip's dispersive
as well.

I once worked with some miccrostrip couplers at around 2-4 GHz and found
directivity was significantly improved by adding two layers of thin kapton
on top of the coupled region, a solution that went into production.  I
expect that
the usual soldermask layer would have about the same effect.


On Thu, Feb 22, 2018 at 8:15 PM, jimlux <> wrote:

> On 2/22/18 12:29 PM, Leo Bodnar wrote:
>> Here is ENIG fact that is not widely known at the moment but which some
>> might find useful.
>> I could not understand why I get better TDR and insertion loss results
>> from solder-mask covered microstrip transmission lines than from otherwise
>> identical microstrips on the same substrate with soldermask removed and,
>> therefore, covered with ENIG.
>> Gold can't be bad, right? As it turns out, even gold coin has two sides
>> to it.
>> I have found that Shlepnev and McMorrow conducted extensive research and
>> published data, some of which is presented here
>> nPresentation_emc2011.pdf
> the ever useful site has an excellent
> discussion of this under the "skin effect" heading.
> _______________________________________________
> time-nuts mailing list --
> To unsubscribe, go to
> ailman/listinfo/time-nuts
> and follow the instructions there.
time-nuts mailing list --
To unsubscribe, go to
and follow the instructions there.

Reply via email to