From: Cosmin Iorga ([email protected])
Date: Thu Aug 03 2000 - 10:02:20 PDT
Does anybody know a field solver that can extract and simulate
a via model from a board database? The via model should include
both signal and return path if the transmission line changes the
reference plane. The following picture tries to illustrate it:
______________________________
|______________________________| <-- trace 1 (top layer)
||
___________________________ || __________________________________
|___________________________ || ________________ground plane 1____|
|| ||
signal via --> || || <-- ground via (return path)
|| ||
___________________________ || ___||_____________________________
|___________________________ || ________________ground plane 2____|
||
_||________________________________
trace 2 (bottom layer)--> |___________________________________|
The signal propagates through trace 1, which is a microstrip
line referenced to ground plane 1, then through the via and
trace 2, which is a microstrip line referenced to ground plane 2.
The return path for the current consists of ground plane 2,
ground via, and ground plane 1. The transition from the top
to the bottom layer will look more inductive if the distance
between the signal and ground vias increases. So far I've tried
XTK and SPECCTRAQuest but none of them could extract correctly
this via model.
Best Regards,
Cosmin Iorga
(818) 874-7149
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