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

Ron Miller (rmiller@Brocade.COM)
Fri, 02 Jul 1999 09:15:04 -0700

--------------D7B37F7A17D7934596F62483
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

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

--------------D7B37F7A17D7934596F62483 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit

<!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                 
     ==========0000-(_)0000=========== 
Brocade Communications Systems, 1901 Guadalupe Parkway, San Jose, CA  95131
rmiller@brocade.com,  rbmiller@sjm.infi.net
  --------------D7B37F7A17D7934596F62483-- **** 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 ****