[SI-LIST] Re: DesignCon presentations posted

  • From: Bill Dempsey <cadcocat@xxxxxxxxx>
  • To: si-list@xxxxxxxxxxxxx
  • Date: Tue, 16 Feb 2010 21:14:49 -0800 (PST)

Istvan,
Ok, still absorbing a lot of great papers here... and
while doing so I seemed to have missed this one:
http://www.simberian.com/AppNotes/DesignCon2010_Paper2807.pdf 
which elaborates a method "similar" to what I proposed.  I use the word 
"similar" very loosely here. :)

In
that paper, the authors state "Conductor resistivity and RMS
measurements of roughness and roughness factor make it possible to
separate all metal losses with high confidence â?? it is impossible to
identify the dielectric properties without such separation in the
model"  You seem to indicate that this might be an issue (re:
cross-correlation).

So what do you (read:Sun) do with regards to
Dk/Df frequency dependence?    What about everyone else out there? 
What's next?  Seems like Simbeor is addressing this in their tools --
anyone else?

...thinking...

Bill


--- On Tue, 2/16/10, Istvan Novak <istvan.novak@xxxxxxx> wrote:

From: Istvan Novak <istvan.novak@xxxxxxx>
Subject: Re: [SI-LIST] Re: DesignCon presentations posted
To: "Bill Dempsey" <cadcocat@xxxxxxxxx>
Cc: si-list@xxxxxxxxxxxxx, Istvan.Novak@xxxxxxx
Date: Tuesday, February 16, 2010, 10:02 PM

Hi Bill,

Yes, all those things you mention are doable, but the challenge is that 
eventually we need a trusted model to fit to, because beyond a few hundred MHz 
there is no direct way to measure the contributing factors separately. AND the 
more cross-correlation we do (for instance different line trace length, 
different line widths, etc) the more we rely on the elusive assumption that 
everything else stays the same except the single
 parameter we intend to change.

Regards,

Istvan Novak
Oracle-SUN


Bill Dempsey wrote:
> <second posting...apologies>
> Hi Istvan,
> I just read the DesignCon paper on the loss tangent measurement and had a 
> question with regards to other possible techniques to measure Df (and 
> similarly Dk).
> Previously you built a stripline test board for measuring glass weave 
> effect.�  The cool thing about this board was that you launched from 
> "inside" the board and minimized the effects of the launch structure.� �  
> Couldn't you build a similar test board with various copper line widths and 
> measure insertion loss on a VNA?�  Once you have the insertion loss, 
> couldn't you then subtract out the Rdc+Rac component from the overall 
> insertion loss to give you a loss curve from which you could derive Df?�  
> Use the various line widths to minimize any weave effect.
> 
> Using this same
 board, can you not look at group delay to also measure the Dk over frequency?
> 
> I know your paper talks about cured and uncured resin variations but in the 
> end, isn't it just the cured value we need?�  Most tools don't address a 
> frequency dependent Df/Dk at this time so what do we do once we get a 
> frequency dependent Dk/Df anyway? I'm curious to see how others are 
> addressing this issue and how much their lab measurements have been off from 
> simulations.
> 
> And I'd like to see some posts from tool vendors who are addressing the 
> frequency dependence of these values.
> 
> Regards,
> Bill
> From: istvan Novak <Istvan.Novak@xxxxxxx>
> To: SI-List
>  <si-list@xxxxxxxxxxxxx>
> Sent: Mon,
 February 15, 2010 10:52:42 PM
> Subject: [SI-LIST] DesignCon presentations posted
> 
> 
> FYI:
> 
> For those of you who could not make it to DesignCon, the Oracle-SUN 
> presentations are posted at http://www.electrical-integrity.com/
> 
> For the three Best Paper Award winner presentations, both the written 
> materials and the slides are posted:
> ââ?¬Å?Introduction and Comparison of an Alternate Methodology for Measuring 
> Loss Tangent of PCB Laminates�
> ââ?¬Å?Additional Trace Losses due to Glass-Weave Periodic Loadingââ?¬ï¿½
> ââ?¬Å?Accuracy Improvements of PDN Impedance Measurements in the Low to 
> Middle Frequency Range�
> 
> Also posted are the slides for the panel discussion "Making Sense out of 
> Dielectric Loss Numbers, Specifications and Test Methods"
> 
> Regards,
>
 
> Istvan Novak
> Oracle-SUN
> 
> 
>   




      


      
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