[SI-LIST] more data on FR4 loss at high freq, FYI
- From: "Greim, Michael" <mgreim@xxxxxxxxxxxx>
- To: "'alexh@xxxxxxxxxxxxxxxx'" <alexh@xxxxxxxxxxxxxxxx>,"'si-list@xxxxxxxxxxxxx'" <si-list@xxxxxxxxxxxxx>
- Date: Fri, 8 Jun 2001 13:51:52 -0400
Here are three more articles sent to me today on
this same subject.
Best Regards,
Michael C. Greim Sonus Networks
mgreim@xxxxxxxxxxxx 978-589-8336
Making the world safe for digital signals everywhere
And all this science I don't understand
It's just my job six days a week
The time is gone. The email's over
Thought I'd something more to say......
-----Original Message-----
From: Chris Mesibov [mailto:Chris.Mesibov@xxxxxxxxxxxxxxx]
Sent: Friday, June 08, 2001 7:58 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: HSPICE W element field solver model
Most PCB fabricators and their lamenate suppliers don't characterize FR4
above
1.5 GHz (i.e. for DK and loss tan). Therefore specifying controlled
impedance
lines intended for this bandwidth should be rejected by any fab house worth
their salt.
The problem is that the studies of FR4 at frequencies up to 10Ghz show
dramatic
changes in loss tan and DK over freq and temp. What this would result in
for
digital signals is group delay and rise time degradation. Group delay is
when
the fourier components of the waveform propagate down the transmission line
at
different rates. The rise time degrades because as the frequency increases,
so
does the loss tangent. This has the effect of attenuating the harmonics of
the
waveform, thus slowing the rise time.
Hope this sheds some light.
Chris
Alex March wrote:
> Dear SI experts,
>
> I would like to ask about your experiences with the
> W element field solver model in HSPICE. I am trying to
> make some simulations in the Gigahertz range with FR4
> material and I am not sure about what value I should
> use for the conductivity of FR4.
>
> Thank you,
>
> Alex
>
>
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--
Chris Mesibov
Sr. Hardware Engineer Fujitsu Network Communications, Inc.
Phone:(845)731-2037 2 Blue Hill Plaza, 6th Floor
Fax: (845)731-2011 Pearl River, NY 10965
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