Hello Jeffrey,

Can you selective plate just the pads?  ENIG can introduce loss
on longer traces.  If you have to plate the tracks themselves, keeping
the trace length to a mimimum will minimise the losses.

As far as impedance is concerned the geometries would be nominally
the same as unplated tracks.

Kind regards
Martyn Gaudion
www.polarinstruments.com



At 13:06 02/12/2004, you wrote:
>How does a nickel-gold finish impact the way you calculate the trace and
>space requirements for constructing a coplanar waveguide? I have a
>calculators for these structures but they assume the conductive features
>to be copper.  I know, from empirical measurements, that solder plating
>has very little effect on these designs, but due to mechanical flatness
>requirements I need a finished surface with less than 0.0003" of
>roughness which can not be produced by HAL.
>
>Jeffrey A McGlaughlin, CID
>Engineering Designer
>Battelle Memorial Institute
>Columbus Ohio
>http://www.battelle.org
>[log in to unmask]
>
>---------------------------------------------------------------------------------
>DesignerCouncil Mail List provided as a free service by IPC using LISTSERV
>1.8d
>To unsubscribe, send a message to [log in to unmask] with following text in
>the BODY (NOT the subject field): SIGNOFF DesignerCouncil.
>To temporarily stop/(restart) delivery of DesignerCouncil send: SET
>DesignerCouncil NOMAIL/(MAIL)
>Search previous postings at: www.ipc.org > On-Line Resources & Databases >
>E-mail Archives
>Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
>for additional information, or contact Keach Sasamori at [log in to unmask] or
>847-615-7100 ext.2815
>---------------------------------------------------------------------------------
>
>______________________________________________________________________
>This email has been scanned by the MessageLabs Email Security System.
>For more information please visit http://www.messagelabs.com/email
>______________________________________________________________________


______________________________________________________________________
This email has been scanned by the MessageLabs Email Security System.
For more information please visit http://www.messagelabs.com/email
______________________________________________________________________

---------------------------------------------------------------------------------
DesignerCouncil Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF DesignerCouncil.
To temporarily stop/(restart) delivery of DesignerCouncil send: SET DesignerCouncil NOMAIL/(MAIL)
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815
---------------------------------------------------------------------------------