Re: [SI-LIST] : Ansoft 2D extractor question

J. Eric Bracken (bracken@ansoft.com)
Fri, 24 Apr 1998 08:53:17 -0400

Just to amplify the correct remarks already made by others:

In Ansoft 2D Extractor, the term "ideal ground" is used during
the 'Conductor Setup' to designate the return path for current flow.
You can define either zero or one "ideal ground" conductors. If
you don't define one, then the solver will take the boundary of
your 2D drawing and treat it as a perfectly conducting piece of
metal which acts as the return path for current.

As Eric Wheatley pointed out, the self-inductance of an isolated wire
with no return path is infinite. If you're looking for the "internal
inductance" of the isolated wire, you can compute this in 2D Extractor
by frequency sweeping the impedance solution. The difference between
the DC inductance value and the high-frequency inductance limit is the
"internal inductance" of the wire.

--Eric

--
J. Eric Bracken, Ph.D.                          Tel: 1.412.261.3200 x135
Group Leader, Signal Integrity R&D              Fax: 1.412.471.9427
Ansoft Corp., Four Station Square, Suite 660    bracken@ansoft.com
Pittsburgh, PA USA 15219-1119                   http://www.ansoft.com