RE: [SI-LIST] : Accuracy of Hspice's W element

Drew Plant (
Thu, 29 Jul 1999 10:50:29 -0700

I doubt if there are any real (=useful) closed-form
solutions for skin loss for stripline or microstrip traces.
Simple equations which assume for instance that the
skin-area in a stripline is planar/parallel to the ground/power
planes just don't work for making predictions of skin loss.

Good field solvers are inherently more accurate, because they take
into account the non-uniformity of the field at the trace edges.


Drew Plant
High-Speed I/O Product R&D
Integrated Circuits Business Division
Hewlett-Packard Company

--> -----Original Message-----
--> From:
--> []
--> Sent: Wednesday, July 28, 1999 7:47 AM
--> To:
--> Subject: RE: [SI-LIST] : Accuracy of Hspice's W element
--> Dmitri,
--> Thank you for posting the explanation.
--> All,
--> The main accuracy issue we've seen with W - elements
--> is not the W element
--> model, but the value we calculate for Rs. For thin
--> lines, at high
--> frequencies, the value for Rs can have a dominant
--> damping effect that causes
--> circuit to work or not work in simulations. I don't
--> seem to be able to get
--> field solvers and closed form equations to all
--> agree. I do have my favorite
--> though. I don't know if this is the forum to talk
--> about individual products
--> though. So I'll refrain.
--> ... Rich

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