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Suitability of Nickel Plating for microwave modules - RF Cafe Forums
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RFpowerJunkie
Post subject: Suitability of Nickel Plating for microwave
modules Posted: Tue Feb 20, 2007 1:57 pm
Lieutenant
Joined:
Tue Feb 20, 2007 1:52 pm
Posts: 3
I’m being forced down a route
to adopt Electroless Nickel plating on aluminium for an enclosure that
will contain a microstrip microwave assembly operating up to 12 GHz.
The RF needs to be launched onto microstrip via an SMA connector
through the nickel plate on the enclosure.
Plating offered is in
the range of 10 - 13 um (more than the skin depth at 12GHz) with a Phosphorous
content of 6 - 12%.
It appears that for optimal electrical properties
Phosphorous content needs to be 1.5 to 3%.
Can anyone advise how
much the insertion loss might change from moving from an aluminium enclosure
to one with Electroless Nickel plating on aluminium?
We have previously
used Electroless Nickel plating on aluminium up to 4 GHz with little
observable effect but are unsure what might happen at higher frequencies
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fred47
Post subject: Nickel platingPosted: Tue
Feb 20, 2007 5:50 pm
General
Joined: Wed Feb 22,
2006 3:51 pm
Posts: 104
Hi!
This is just a generic response
to the question, as I don't have specific experience with the exact
question.
As always at frequencies in that range, surface roughness
is a strong contributor to loss. Of course, the electrical conductivity
of the nickel is important, too.
So the big question is, what
will your surface roughness be, after plating?
Good Luck,
Fred
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Joe
Post subject: Electroless NickelPosted:
Tue Feb 20, 2007 6:19 pm
Captain
Joined: Fri Feb 17,
2006 6:25 pm
Posts: 6
Location: US
I've used Electroless Nickel
plating to 20GHz with no apparent degradation. In microstrip, most of
the fields are confined to the ground plane of your substrate. Except
for the transitions, the nickel will not have much effect. If you are
looking to squeeze every last .1dB, there may be some additional loss,
but in general there isn't a signifiicant difference.
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RFpowerJunkie
Post subject: Posted: Wed Feb 21, 2007 5:39
am
Lieutenant
Joined: Tue Feb 20, 2007 1:52 pm
Posts:
3
Thanks for the advice Guys.
Can anyone suggest who might
be the best company to approach in the UK for plating microwave enclosures?
I neglected to say I plan to glue the microwave assemblies to the
enclosure with a thin layer of silver loaded epoxy.
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Joe
Post subject: Electroless NickelPosted: Wed Feb 21,
2007 3:08 pm
Captain
Joined: Fri Feb 17, 2006 6:25 pm
Posts: 6
Location: US
Can't help on plating vendors on your side
of the pond.
You didn't mention what substrate or carrier, if
any, you are using. I would recommend an epoxy preform if you are going
to see much temperature variation in further processing or in operation.
Check the thermal coefficients of expansion for the aluminum and for
your substrate and carrier.
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RFpowerJunkie
Post subject: Posted: Thu Feb 22, 2007 5:23 am
Lieutenant
Joined: Tue Feb 20, 2007 1:52 pm
Posts: 3
Substrate will
be Rogers 5880 at 15" or 20" thou.
My assumption is that the
surface roughness of the plated finish is largly determined by that
of the Aluminium underneath and that the plating will tend to smooth
the milling cutter chatter marks left in the Aluminium .
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Joe
Post subject: Posted: Mon Feb 26, 2007 4:36 pm
Captain
Joined: Fri Feb 17, 2006 6:25 pm
Posts: 6
Location: US
Once you launch to the microstrip on the 5880, most
of the currents will be in the copper clad unless the copper thickness
is not thick enough. I doubt that the housing finish will be a large
contributor to insertion loss.
Posted 11/12/2012
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