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

Chung, Chee Yee ([email protected])
Thu, 23 Apr 1998 18:44:00 -0700

not sure the exact problem but hope to provide some insight.

when you calculate for microstrip line, you had a ground plane.

believe Ansoft 2D calculates the loop inductance and not partial. so,
problem 1 and 2 could be tricky for Ansoft 2D solver.

Change the problem space (the box used where all the models are in) and
believe you are going to see different results.

my suggestion is always define a ground return (i assume you did not
define them in problem 1 and 2) when using Ansoft 2D or you might need
to blow the solvingn region real big.


______________________________ Reply Separator
Subject: [SI-LIST] : Ansoft 2D extractor question
Author: Grasso, Charles (Chaz) [SMTP:[email protected]] at
Date: 4/23/98 1:56 PM

This question is for anyone who uses the Ansoft 2D extractor..

I have been using this s/w for about 4 months and, in my innocence,
have been attempting to "calibrate" the answers. For example, I
plugged in a simple microstrip and behold - I got the right answers for

Problem 1..
I then tried to get the Zo of a two wire configuration. The
wires are 20mils diameter and spaced (center to center) 50mils apart.

Accepted calculations indicate that the Zo should = 188 ohms. The
2DExtractor gives me an answer of 14 ohms!!

Problem 2..
I then tried to get the inductance of a 2 meter length of 28AWG wire.
Measurements (@1kHz) gave an answer of 2.1uH.
Formulae gave an answer of 3.748uH.
2DE gave an answer of 0.5uH

Can somebody explain what is going on??

Thank you
Charles Grasso
EMC Engineer
2270 Sth 88th Street
Louisville CO 80027 MS 4262
[email protected]
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