Re[2]: [SI-LIST] : Parallel tracks on Flexible PCB without G

mcheong@molex.com
Fri, 2 Jul 1999 13:13:28 -0500

Cai,

Per Ron's message below, you can also download the free software AppCAD from
HP...

It has an impedance calculator for the various transmission line structures (or
passive circuits), including coplanar waveguide (with & without ground plane).
It's very useful if you want a first pass look at the impedance of any line.

Enjoy......

Michael Cheong
*****************************************
Sr. Product Design Engineer, Advanced Development
Molex Incorporated
email: mcheong@molex.com

Tel: (630)-527-4257
Fax: (630)-969-1352
2222 Wellington Court
Lisle, IL 60532
*****************************************

____________________Reply Separator____________________
Subject: Re: [SI-LIST] : Parallel tracks on Flexible PCB without Grou
Author: Ron Miller <rmiller@Brocade.COM>
Date: 7/2/99 9:15 AM

Cai

The signal with grounds either side is referred to as co-planar waveguide in
microwave terms and there are many simulators for that impedance. Try the
IEEE MTT Proceedings for papers on the subject. If you want a tool that
can simulate it RF Design Magazine has a series of software routines donated
from many
engineers over the years. If you want a commercial tool to simulate it Try
HPEEsof
Touchstone, which used to cost about $500 for a dos version and more for windows
versions.

In the case of a signal with a ground on only one side I would look for an
offset
coplanar waveguide model and extend the unused groundplane to the limits of the
model.

Ron MIller

CAI ZhongPing wrote:

> Dear experts,
>
> Sorry to disturb you again. :) The following figure explains the case more
clearly:
>
> ________ ________ ________ ________
> |________| |________| |________| |________|
> GND Signal GND Signal
>
> So they are not driven differentially. General tools calculate differential
impedance, right? Can just setting the distance to the plane very high get
correct result?
>
> Thanks for your help and look forward to your reply.
>
> Cai
>
> **** To unsubscribe from si-list: send e-mail to majordomo@silab.eng.sun.com.
In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP.
si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****

--
Ronald B. Miller  _\\|//_  Signal Integrity Engineer
(408)487-8017    (' 0-0 ') fax(408)487-8017
     ==========0000-(_)0000===========
Brocade Communications Systems, 1901 Guadalupe Parkway, San Jose, CA  95131
rmiller@brocade.com,  rbmiller@sjm.infi.net

<!doctype html public "-//w3c//dtd html 4.0 transitional//en"> Cai

The signal with grounds either side is referred to as co-planar waveguide in
microwave terms and there are many simulators for that impedance.  Try the
IEEE MTT Proceedings for papers on the subject.  If you want a tool that
can simulate it RF Design Magazine has a series of software routines donated from many
engineers over the years.  If you want a commercial tool to simulate it Try HPEEsof
Touchstone, which used to cost about $500 for a dos version and more for windows
versions.

In the case of a signal with a ground on only one side I would look for an offset
coplanar waveguide model and extend the unused groundplane to the limits of the
model.

Ron MIller

CAI ZhongPing wrote:

Dear experts,

Sorry to disturb you again. :)  The following figure explains the case more clearly:

   ________    ________    ________    ________
  |________|  |________|  |________|  |________|
     GND        Signal       GND        Signal

So they are not driven differentially. General tools calculate differential impedance, right? Can just setting the distance to the plane very high get correct result?

Thanks for your help and look forward to your reply.

Cai

**** To unsubscribe from si-list: send e-mail to majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP.  si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****

-- 
Ronald B. Miller  _\\|//_  Signal Integrity Engineer
(408)487-8017    (' 0-0 ')
fax(408)487-8017          &nbs
p;      
     ==========0000-(_)0000=========== 
Brocade Communications Systems, 1901 Guadalupe Parkway, San Jose, CA  95131
rmiller@brocade.com,  rbmiller@sjm.infi.net
  **** To unsubscribe from si-list: send e-mail to majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****