[SI-LIST] Re: 3D-em simulation and terminations: macromodelling
- From: "jian" <jian@xxxxxxxxxx>
- To: "'Istvan Nagy'" <buenos@xxxxxxxxxxx>, <si-list@xxxxxxxxxxxxx>
- Date: Mon, 5 Jan 2009 14:59:18 -0800
Hi, Istvan:
S-parameter are similar to Y-parameter and Z-parameter. It contains a
complete description of the system performance of a linear system. It is
independent of excitations and terminations. Given the s-parameters with
specific terminations (or Zc), the excitations and terminations, you are
able to find the voltage and current at all the ports of a linear system in
both frequency domain and time domain.
Best regards,
----------------------------------------------------------------------------
------
Jian X. Zheng, Ph.D.
Zeland Software, Inc.
48834 Kato Road, 103A, Fremont, CA 94538, U.S.A.
Tel: 510-623-7162, Fax: 510-623-7135, www.zeland.com
----------------------------------------------------------------------------
------
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of Istvan Nagy
Sent: Monday, January 05, 2009 1:34 PM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] 3D-em simulation and terminations: macromodelling
hi
if i simulate a pcb structure (a microstrip trace) with an 3d
electromagnetics simulator to create a macromodell (s-parameter touchstone
file), then do i have to connect terination resistors in the em simulation
setup? or all the ports in all simulators are automatically terminations
too? do i have to use the same term.resistor value in system simulation too
(when using the macromodel. example in Agilent ADS or spice) to get accurate
results?
the problem is that in the em simulation we can not use the correct
termination, since it comes with using IBIS buffer models and those are not
compatible with any of the EM simulators, they can be connected in a circuit
simulator only. so do macromodelling: first EM simulation, create
macromodel, then system simulation with the other elements of the signal
path.
I was thinking:
if the S parameter data ( S21(f) ) should depend on the actual
termination?
if we change the termination of a transmission line, then it changes the
reflections (matched, unmatched...as we studied in the school). is it the
same when we use an s-param (touchstone) macromodel instead of the real
tline?
if i dont terminate in the em simulator, then the strong reflections will
cause strong loss and not-flat response, and that loss will go into the
s-param file. then if i connect correct termination in the system level
simulation, it will not to fix those reflections/loss anymore.
am i right?
so, how much usable is an s-parameter macromodell, and macromodelling
anyway?
Istvan Nagy
CCT
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
