FreeLists / si-list / [SI-LIST] Re: Serpentine/Spiral Lines (was Re: Trace Bends)

["Tsuk, Michael" <Michael.Tsuk@xxxxxxxxxx>]

Chris Padilla wrote:

> "FDTD Analysis of Conventional and Novel Delay Lines" by Omar M. =
Ramahi (he=20
> is the co-author of a great little handbook: "EMI/EMC Computational=20
> Modeling Handbook")  Try him at Omar.Ramahi@xxxxxxxxxx but I've no =
clue if=20
> that email address is still viable...I have my doubts! :|

No, Omar isn't at Compaq anymore; he's now at the University of =
Maryland.  His new email address is:
oramahi@xxxxxxxxxxxxxx

--=20
Michael Tsuk
Compaq AlphaServer Platform Group
(508) 467-4621



-----Original Message-----
From: Chris Padilla [mailto:cpad@xxxxxxxxx]
Sent: Wednesday, May 01, 2002 1:46 PM
To: SI-List Discussion Group
Subject: [SI-LIST] Serpentine/Spiral Lines (was Re: Trace Bends)



This is slightly off-topic of trace bends but one of the main reasons =
some=20
of us worry about trace bend is they are chiefly used to create time=20
delays.  This method is known as "serpentining."

There was a paper presented at the 16th Annual Applied Computational=20
Electromagetics symposium presented at the Naval Postgraduate School in=20
Monterey, CA from March 20-24, 2000.

"FDTD Analysis of Conventional and Novel Delay Lines" by Omar M. Ramahi =
(he=20
is the co-author of a great little handbook: "EMI/EMC Computational=20
Modeling Handbook")  Try him at Omar.Ramahi@xxxxxxxxxx but I've no clue =
if=20
that email address is still viable...I have my doubts! :|

Basically, the paper talks about delay lines and minimizing crosstalk =
while=20
maintaining the same spacing and density of the serpentined line.  The=20
conclusion is to use a spiral method of delay line.  This is difficult =
to=20
describe without a picture, unfortunately.

Being an EMI Engineer, I wonder about the EMI radiation from such a=20
structure as a whole rather than just the many 90-degree bends present!

Two references were sited:

R-B. Wu and F-L. Chao, Laddering wave in serpentine delay line, IEEE =
Trans.=20
Components, Packaging and Manufacturing Tech., Part B: Advanced =
Packaging=20
vol. 18, no. 4, pp. 644-650, Nov. 1995.

R-B. Wu and F-L. Chao, Flat spiral delay line design with minimum =
crosstalk=20
penalty, IEEE Trans. Components, Packaging and Manufacturing Tech., Part =
B:=20
Advanced Packaging vol. 19, no. 2, pp. 397-402, May 1996.

Thanks----->Chris


>As a follow-up to this subject, there was a paper
>presented at the Denver EMC symposium
>(1998 I believe) which stated a *lowering* of
>emissions from serpentine construction of traces.
>Can't remember who presented it nor what
>speed of signals were involved.
>
>Regards, Doug McKean

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