Are both reference planes well coupled?

Out of interest, if you fire over the geometry and Dk's and Df's I'll give you a non-Polar model. Might even chuck in the
susceptibilities as well.


Best Regards

David Greig
______________________________
GigaDyne Ltd
Buchan House
Carnegie Campus
Dunfermline KY11 8PL
United Kingdom
t: +44 (0)1383 624 975
www.gigadyne.co.uk
______________________________

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jim Henderson
Sent: 15 November 2005 14:28
To: [log in to unmask]
Subject: [TN] impedance testing

Hello,

If there are any impedance testing gurus out there I have a question for you.  We are testing an edge coupled offset strip line
coupon.  We modeled the stack up to give us 100 ohms differential.  When we test the coupon we get around 130 ohms.  We have
done a microsection of the coupon and modeled the coupon data and Polar says we should have 105 ohms, within tolerance.
We had a 4 panel lot and it is consistent across the board.  The coupon is constructed correctly.  My question is, other than
what I am seeing on the microsection should I look for to find the culprit of the high reading?  Any help would be great.

Jim Henderson
Colonial Circuits

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