[SI-LIST] Re: Dust and humidity impact on the signal
- From: Alan Hilton-Nickel <Alan.Hiltonnickel@xxxxxxx>
- Date: Wed, 17 Jan 2007 10:45:39 -0800
Considering that dust is something that randomly collects on a surface,
has little mass (as individual particles) and, unless
manipulated/compressed, is mostly comprised of air, I would expect it to
not change the Er at all. Might be an interesting experiment to measure
the Er of various kinds of dust, both natural and compacted (that'd be a
lot of dust). Problem is, there are a lot of different sources of dust.
Yes, sawdust and pet hair, but also shed human skin, soot, pollen, and
dirt, spider webs. Even dust due to dirt can have different compositions
from clay to decomposing leaves to worm casings.
What's the Er of worm poop?
Alan
(Who has clearly spent wayy too much time in his attic lately)
Loyer, Jeff wrote On 01/17/07 10:06,:
>It should be representative dust, with its corresponding Er. I don't
>think sawdust is a representative component, unless you've got your
>workshop in the kitchen (not that there's ANYTHING wrong with that,
>Scott, if you do - grin). =20
>
>I would propose dog or cat hair as a better material to spread over your
>board before TDR'ing it. If the study is taken to its extremes, the Er
>of various breeds could be determined, and characteristic impedance
>taken into account when visiting the pound.
>
>I hope the study finds a negligible effect due to dust - every home
>computer I've ever worked on has incredible amounts of dust. Maybe
>another reason to recommend stripline. :-)
>
>Cheers,
>Jeff Loyer
>
>-----Original Message-----
>From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
>On Behalf Of Scott McMorrow
>Sent: Wednesday, January 17, 2007 9:39 AM
>To: Fabrizio.Zanella@xxxxxxx
>Cc: Dorin.Oprea@xxxxxxxxxxxxxxxxxx; si-list@xxxxxxxxxxxxx
>Subject: [SI-LIST] Re: Dust and humidity impact on the signal
>
>To follow up, accommodation of the impact of humidity on Er and loss=20
>tangent should be fairly easy, although I've not tried it.
>
>1) Dry out your target material in an autoclave
>2) Weigh it.
>3) Place the material in a humidity chamber
>4) Weigh it.
>5) Compute the percentage water by weight.
>6) Compute the average increase in Er and loss tangent by using the=20
>ratios of dielectric and absorbed water.
>
>Once you know these, it should be possible to create a lossy dielectric=20
>model that is a pretty close match for 2D or 3D solvers. For extra=20
>credit, actual material measurements could be made using one of the many
>
>methods know for Er and TanD extraction, at multiple frequency points,=20
>to create a more precise frequency dependent model. However, I think if
>
>you perform steps 1 to 6 above you'll be closer than you might imagine=20
>(assuming that you know your original material properties well.
>
>I wouldn't worry much about dust, except for microstrip. In that case,=20
>I guess one could make some TDR measurements with and without dust and=20
>see what happens. (It's not like it's hard to create some good dust ...=20
>just get yourself a good circular saw, create some fine dust, and=20
>sprinkle it over the trace.
>
>
>Scott McMorrow
>Teraspeed Consulting Group LLC
>121 North River Drive
>Narragansett, RI 02882
>(401) 284-1827 Business
>(401) 284-1840 Fax
>
>http://www.teraspeed.com
>
>Teraspeed(r) is the registered service mark of
>Teraspeed Consulting Group LLC
>
>
>
>Fabrizio.Zanella@xxxxxxx wrote:
>
>
>>Dorin, there's a good paper from DesignCon 2004 which has information
>>
>>
>on
>
>
>>measurements on serial links including the effect of temperature and
>>humidity=3D2E
>>'The Impact of Environmental Conditions on Channel Performance', by
>>
>>
>Greg
>
>
>>Sheets, Agere and John D'Ambrosia, Tyco=3D2E You can take the dk
>>information and apply it as a variable in a 3D simulator, and then use
>>
>>
>a
>
>
>>parametric sweep=3D2E
>>
>>I can send you this paper if you're interested=3D2E
>>
>>Regards,
>>
>>Fabrizio Zanella
>>
>>
>>-----Original Message-----
>>From: Dorin=3D2EOprea@alcatel-lucent=3D2Ecom
>>[mailto:Dorin=3D2EOprea@alcatel-lucent=3D2Ecom]
>>Sent: Wednesday, January 17, 2007 10:59 AM
>>To: si-list@freelists=3D2Eorg
>>Subject: [SI-LIST] Dust and humidity impact on the signal
>>
>>Hi,
>>
>>I try to simulate the dust and humidity impact on 10G differential
>>signal routed as micro strip on the board=3D2E I know that the dust
>>thickness and humidity can vary significantly, but I wonder what would
>>be a good approach, for start, to build the corresponding model in a
>>
>>
>3D
>
>
>>simulation tool (suggestions on dk, df)=3D2E
>>
>>Thanks,
>>Dorin
>>
>>
>>
>>------------------------------------------------------------------
>>To unsubscribe from si-list:
>>si-list-request@freelists=3D2Eorg with 'unsubscribe' in the Subject
>>
>>
>field
>
>
>>or to administer your membership from a web page, go to:
>>http://www=3D2Efreelists=3D2Eorg/webpage/si-list
>>
>>For help:
>>si-list-request@freelists=3D2Eorg with 'help' in the Subject field
>>
>>List FAQ wiki page is located at:
>> http://si-list=3D2Eorg/wiki/wiki=3D2Epl?Si-List_FAQ
>>
>>List technical documents are available at:
>> http://www=3D2Esi-list=3D2Eorg
>>
>>List archives are viewable at:
>>http://www=3D2Efreelists=3D2Eorg/archives/si-list
>>or at our remote archives:
>> http://groups=3D2Eyahoo=3D2Ecom/group/si-list/messages
>>Old (prior to June 6, 2001) list archives are viewable at:
>> http://www=3D2Eqsl=3D2Enet/wb6tpu
>>
>>
>>------------------------------------------------------------------
>>To unsubscribe from si-list:
>>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>>
>>or to administer your membership from a web page, go to:
>>//www.freelists.org/webpage/si-list
>>
>>For help:
>>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>>
>>List FAQ wiki page is located at:
>> http://si-list.org/wiki/wiki.pl?Si-List_FAQ
>>
>>List technical documents are available at:
>> http://www.si-list.org
>>
>>List archives are viewable at: =20
>> //www.freelists.org/archives/si-list
>>or at our remote archives:
>> http://groups.yahoo.com/group/si-list/messages
>>Old (prior to June 6, 2001) list archives are viewable at:
>> http://www.qsl.net/wb6tpu
>> =20
>>
>> =20
>>
>>
>------------------------------------------------------------------
>To unsubscribe from si-list:
>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
>or to administer your membership from a web page, go to:
>//www.freelists.org/webpage/si-list
>
>For help:
>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
>List FAQ wiki page is located at:
> http://si-list.org/wiki/wiki.pl?Si-List_FAQ
>
>List technical documents are available at:
> http://www.si-list.org
>
>List archives are viewable at: =20
> //www.freelists.org/archives/si-list
>or at our remote archives:
> http://groups.yahoo.com/group/si-list/messages
>Old (prior to June 6, 2001) list archives are viewable at:
> http://www.qsl.net/wb6tpu
> =20
>------------------------------------------------------------------
>To unsubscribe from si-list:
>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
>or to administer your membership from a web page, go to:
>//www.freelists.org/webpage/si-list
>
>For help:
>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
>
>List technical documents are available at:
> http://www.si-list.net
>
>List archives are viewable at:
> //www.freelists.org/archives/si-list
>or at our remote archives:
> http://groups.yahoo.com/group/si-list/messages
>Old (prior to June 6, 2001) list archives are viewable at:
> http://www.qsl.net/wb6tpu
>
>
>
>
--
Alan Hilton-Nickel
Signal Integrity Engineer
Sun Microsystems Inc.
Netra Systems and Networking
Newark, CA
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
