RE: [SI-LIST] : even-odd mode influence

John Williamson (williamj@nortelnetworks.com)
Fri, 16 Jul 1999 08:57:05 -0500

Folks,

A comment on HSPICE lossy coupled T-line accuracy. Be careful when using the
W-element.
We've found that the time and frequency domains do not agree. For example, a
set of extracted
RLGC parameters resulted in a frequency domain attenuation of -25dB at
10GHz. However when
the same model was used in the time domain driven by a 10GHz sine wave, the
attenuation was
only -8dB. We've found that this can be corrected by dividing the model up
into several shorter
ones. It's not computationally efficient, but it works fairly well.

Regards,

jw

John M. Williamson, 0V30, Electromagnetic & interconnect technology
Nortel Networks
(613) 763 3198, ESN 393-3198 E-mail: williamj@nortel.ca

> -----Original Message-----
> From: jaydiep@us.ibm.com [SMTP:jaydiep@us.ibm.com]
> Sent: Thursday, July 15, 1999 4:49 PM
> To: si-list@silab.eng.sun.com
> Subject: [SI-LIST] : even-odd mode influence
>
>
>
> Weber,
>
> To be able to simulate even-odd mode effects, you'll have to model the
> conductors as a system of coupled transmission lines. There are not many
> simulators that can do it, and even the ones that can are pretty limited
> to the
> number of conductors they can handle. Many of them can only handle lumped
> models, where what you really need to see what's going on is a true
> distributed
> model. You'll need a field solver to extract the coupled transmission
> line
> matrices - it's not easily done analytically. Take a look at Ansoft,
> Applied
> Simulation Technology, and Pacific Numerix. HSPICE can model coupled
> lines
> using geometric input (conductor size, spacing, etc.), but I can't vouch
> for its
> accuracy.
>
> Jay Diepenbrock
>
> Senior Engineer
> Interconnect Technology & Qualification
> IBM Global Procurement, B8UA/061, RTP, NC
> Phone: 919-543-8804 Fax: 919-543-3642
> Email: jaydiep@us.ibm.com
>
>
>
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