[SI-LIST] [Fwd: RE: Re: dielectric loss question]
- From: Jim G Roberts <jgroberts@xxxxxxxxxx>
- To: Silqun Leung <SLeung@xxxxxxxxxx>, SI list <si-list@xxxxxxxxxxxxx>
- Date: Tue, 18 Feb 2003 15:36:51 +0100
Silqun,
As far as I remember these are collected data from different
munufacturers but based on data measured or confirmed by measurement.
I have added additional info from another source where the source of the
data is given (DDI).
Regards,
Jim
-------- Original Message --------
Subject: RE: [SI-LIST] Re: dielectric loss question
Date: Mon, 17 Feb 2003 13:11:26 -0500
From: Silqun Leung <SLeung@xxxxxxxxxx>
To: "'Jim G Roberts'" <jgroberts@xxxxxxxxxx>
Jim,
Thanks for the presentation. Am I correct in assuming that the data
on the last plot with attenuation due to surface roughness is simulated
data?
Thanks,
Silqun
> -----Original Message-----
> From: Jim G Roberts [mailto:jgroberts@xxxxxxxxxx]
> Sent: Friday, February 14, 2003 1:41 PM
> To: Silqun Leung
> Subject: Re: [SI-LIST] Re: dielectric loss question
>
>
> Hi Silqun,
> This applies to PCB but it also applies to microwave
> transmission. Jim
>
> Silqun Leung wrote:
>
> > Jim,
> > I'm interested in seeing the ppt file regarding
> losses due to
> > surface roughness. Exactly what application does this presentation
> > apply
> > to: PCB design or packaging?
> >
> > Thanks,
> >
> > Silqun
> >
> > > -----Original Message-----
> > > From: Jim G Roberts [mailto:jgroberts@xxxxxxxxxx]
> > > Sent: Wednesday, February 12, 2003 9:23 AM
> > > To: milabont@xxxxxxxxx
> > > Cc: 'Si-List' (E-mail)
> > > Subject: [SI-LIST] Re: dielectric loss question
> > >
> > >
> > >
> > > Mike, Peter,
> > > It is also interesting that since data rate are
> in the 10GHz
> > > rates that the surface roughness begins to give a large
> percentage
> > > of the losses. These are also very frequency sensitive. If of
> > > interest I have a PPT file.
> > >
> > > --
> > > Regards, __________ James G Roberts
> > > /___ ____ | jrobert@xxxxxxxxxxxxxxxxxxxxx
> > > Jim __ / /___/ / jgroberts@xxxxxxxxxx
> > > / /_/ /---| | Room: BE436, Hilversum
> > > \____/ /_/ Tel: +31 35 687 4308 Fax: 5976
> > >
> > > Mike LaBonte wrote:
> > >
> > > > I don't have any info specific to moisture in PCBs. 2.45GHz
> > > is where
> > > > the dielectric permittivity of water begins to decrease
> > > significantly,
> > > > but it is not a peak absorption frequency. Peak dielectric loss
> > > > for water occurs in the range of 10GHz to 160GHz,
> depending on the
> > > > temperature. The peak frequency is higher for higher
> > > temperatures. At
> > > > 25degC the peak is near 40GHz.
> > > >
> > > > At DesignCon 2000 Howard Johnson presented "Multi-Level
> > > Signaling", in
> > > > which he gave the rate of change for signal degradation due to
> > > > skin effect and dielectric loss at 20dB/decade near 1-2GHz. At
> > > least half
> > > > of that is dielectric loss. But the paper also shows noise
> > > increasing
> > > > at 20dB/decade, and SNR falling to zero under 10GHz.
> > > >
> > > > My take on it is that water will not be the main cause of
> > > signal loss.
> > > >
> > > > http://www.sbu.ac.uk/water/microwave.html
> > > > http://signalintegrity.com/Pubs/misc/mls.htm
> > > >
> > > > Mike LaBonte
> > > >
> > > > -----Original Message-----
> > > > From: si-list-bounce@xxxxxxxxxxxxx
> > > > [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Peter Arnold
> > > > Sent: Tuesday, February 11, 2003 2:35 PM
> > > > To: 'Si-List' (E-mail)
> > > > Subject: [SI-LIST] dielectric loss question
> > > >
> > > > All,
> > > >
> > > > A question from the curious - in high-speed signaling
> > > environments we
> > > > may create time-varying electric fields that have
> > > components close to
> > > > the frequency used to heat water in microwave ovens,
> > > somewhere around
> > > > 2.45GHz. This suggests a portion of dielectric loss at these
> > > > frequencies might be due to dielectric heating of any moisture
> > > > that might be present in the fiberglass.
> > > >
> > > > Is this in fact the case, and what magnitude is the effect
> > > at normal
> > > > humidities? Does loss increase in real multi-GHZ signaling
> > > systems as
> > > > dielectric moisture content increases?
> > > >
> > > > Thank you,
> > > > peter arnold.
> > > >
> > > >
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>
> --
> Regards, __________ James G Roberts
> /___ ____ | jrobert@xxxxxxxxxxxxxxxxxxxxx
> Jim __ / /___/ / jgroberts@xxxxxxxxxx
> / /_/ /---| | Room: BE436, Hilversum
> \____/ /_/ Tel: +31 35 687 4308 Fax: 5976
>
>
>
-- Binary/unsupported file stripped by Ecartis --
-- Type: application/pdf
-- File: surf_rough1.pdf
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