[SI-LIST] Fw: Re: Dielectric constant measuring

Presumably you are measuring microstrip.  The dielectric constant you
computed includes signal traveling in the air above the microstrip.  You
are getting a composite measurement of air and laminate, and that is why
the answer is less than that of the laminate alone.
 
Orin
 
On Tue, 23 Oct 2007 11:38:46 -0700 (PDT) ma mu <sitaskina@xxxxxxxxx>
writes:
> Hi ,
>    
>    I am trying to measure the dielectric constant value of our ckt  
> at 100mhz -3 Ghz in our lab. I have measured it but the value is too 
> low 2.5 ( expectiing value is  between 3.2 to 3.5) .
>    
>   I have used Iconnect software to measure the transient time for an 
> electromagnetc pulse to travel the length of my transmission line.
>    
>   and the formula I have used is following:
>   td=measured data 
>   l=length of the transmission line
>   Vc= velocity of light. 
>    
>   Er= (Vc*Vc*td*td)(l*l)
>    
>   the TDR I have used has 35 ps rise time . 
>    
>    
>   please let me know why I did get this low value. or you could 
> recommend me to find a way to get Er value. I will appreciate your 
> help.
>    
>    
>   Ma
> 
>   Steve,
> 
> Thanks for the plug! Sometimes the best solutions are the easiest!
> 
> Lee
> 
> 
> > [Original Message]
> > From: steve weir 
> > To: 
> > Cc: QU Perry 
> ; si-list
> 
> > Date: 9/15/2007 12:10:47 PM
> > Subject: Re: [SI-LIST] Re: fiber-weave effect alive and well?
> >
> > In the shameless plug for someone else dept: Lee's book "Right the 
> 
> > First Time Volume 2" does do a nice job of demonstrating the 
> difference 
> > between various weaves including some good cross-section 
> > microphotographs and TDR plots. I think it is worth the price of 
> the 
> > book for that information alone.
> >
> > Steve
> > Lee Ritchey wrote:
> > > The link to the Circuitree web site requires each person to 
> register and
> > > obtain a password.
> > >
> > > It is true that the thinner weaves are the problem.
> > >
> > > I cover these weaves and results in Chapter 5 of Volume 2 of my 
> book. 
> > > There are photos showing what the weaves look like compared to a 
> 3.5
> mil
> > > trace. Also show what vias do to very fast signals.
> > >
> > > Lee Ritchey
> > >
> > >
> > > 
> > >> [Original Message]
> > >> From: QU Perry 
> 
> > >> To: si-list 
> > >> Date: 9/14/2007 12:25:54 PM
> > >> Subject: [SI-LIST] Re: fiber-weave effect alive and well?
> > >>
> > >> I would be interested to see a link as well.
> > >>
> > >> Jeff's paper on DesignCon2007 is convincing to me that this is
> something
> > >> we need to pay attention. Real life design will probably not be 
> as bad
> > >> as the theoretical estimate since most of the diff pair routing 
> we have
> > >> on the PCB is not likely to run a long length non-stop in 
> parallel with
> > >> edge. The "jog" as is called in the paper is very common due to 
> vias
> etc
> > >> and pretty random.
> > >>
> > >> Also from the data we got from PCB vendor, it appears that 
> thinner
> > >> dielectric substrate the worse fibre weave effect as the gap 
> between
> the
> > >> fiber is larger. Has this been looked at ?
> > >>
> > >> Regards
> > >>
> > >> Perry
> > >>
> > >>
> > >> 
> > >
>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
3D=
> > > 
> > >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=20
> > >>
> > >> Perry Qu=20
> > >>
> > >> Design & Qualification, Alcatel-Lucent Canada Inc.
> > >>
> > >> 600 March Road, Ottawa ON, K2K 2E6, Canada=20
> > >>
> > >> DID: 613-7846720 Fax: 613-5993642=20
> > >>
> > >> Email: perry.qu@xxxxxxxxxxxxxxxxxx=20
> > >>
> > >>
> > >> 
> > >
>
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
3D=
> > > 
> > >> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=20
> > >>
> > >> =20
> > >>
> > >> 
> > >>> -----Original Message-----
> > >>> From: si-list-bounce@xxxxxxxxxxxxx=20
> > >>> [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of=20
> > >>> Aubrey_Sparkman@xxxxxxxx
> > >>> Sent: Friday, September 14, 2007 1:59 PM
> > >>> To: leeritchey@xxxxxxxxxxxxx; rdudek@xxxxxxxxxxxxxxx;=20
> > >>> si-list@xxxxxxxxxxxxx
> > >>> Subject: [SI-LIST] Re: fiber-weave effect alive and well?
> > >>> =20
> > >>> Would you like to share a link?=3D20
> > >>> =20
> > >>> =20
> > >>> Aubrey Sparkman=3D20
> > >>> Enterprise Engineering Signal Integrity Team=3D20 Dell, 
> Inc.=3D20=20
> > >>> Aubrey_Sparkman@xxxxxxxx=3D20
> > >>> (512) 723-3592=3D20
> > >>> "Discovery consists of seeing what everybody has seen and=20
> > >>> thinking what nobody else has thought." - Jonathan Swift
> > >>> =20
> > >>> =20
> > >>> -----Original Message-----
> > >>> From: si-list-bounce@xxxxxxxxxxxxx=20
> > >>> [mailto:si-list-bounce@xxxxxxxxxxxxx]
> > >>> On Behalf Of Lee Ritchey
> > >>> Sent: Friday, September 14, 2007 11:36 AM
> > >>> To: Russell S. Dudek Jr.; si-list@xxxxxxxxxxxxx
> > >>> Subject: [SI-LIST] Re: fiber-weave effect alive and well?
> > >>> =20
> > >>> We already have a glass weave solution. Check my column in=20
> > >>> the April issue of Circuitree magazine.
> > >>> =20
> > >>> Lee Ritchey
> > >>> =20
> > >>> =20
> > >>> 
> > >>>> [Original Message]
> > >>>> From: Russell S. Dudek Jr. 
> > >>>> To: 
> > >>>> Date: 9/12/2007 1:10:28 PM
> > >>>> Subject: [SI-LIST] Re: fiber-weave effect alive and well?
> > >>>>
> > >>>> Steve,
> > >>>> =3D20
> > >>>> I agree, Fiber Weave Effect (FEW) has most certainly been=20
> > >>>> 
> > >>> confirmed by
> > >>> such
> > >>> 
> > >>>> research. However, there is a new change in the wind. I=20
> > >>>> 
> > >>> have the=3D20=20
> > >>> 
> > >>>> unique opportunity, as a technical liaison, to enable a=20
> > >>>> 
> > >>> technology=3D20=20
> > >>> 
> > >>>> that may put
> > >>>> 
> > >>> an
> > >>> 
> > >>>> end to FWE as a consideration in high-speed designs. We=20
> > >>>> 
> > >>> all know that
> > >>> =20
> > >>> 
> > >>>> the crux of the matter is the glass weave and its effect 
> on=20
> > >>>> 
> > >>> localized
> > >>> Er.
> > >>> 
> > >>>> Either get ride of the reinforcement layer completely or 
> more=3D20=20
> > >>>> challenging change the fundamentals of the glass weave 
> fabrication
> > >>>> 
> > >>> process (GWFP).
> > >>> 
> > >>>> =3D20
> > >>>> We have taken the more challenging (and fun) approach and 
> have=20
> > >>>> rocked=3D20 the fundamentals the GWFP. I cannot disclose much 
> the=20
> > >>>> specifics of=3D20 the technology and our partners in such 
> an=20
> > >>>> 
> > >>> open forum. =20
> > >>> 
> > >>>> However, if=3D20 you are interested learning more feel 
> free=20
> > >>>> 
> > >>> to contact=20
> > >>> 
> > >>>> me and we can=3D20 get the proper NDAs in place to 
> facilitate=20
> > >>>> 
> > >>> such a discussion.
> > >>> 
> > >>>> =3D20
> > >>>> RD
> > >>>> =3D20
> > >>>> Russell Dudek
> > >>>> Technology Specialist
> > >>>> Compunetics, Inc.
> > >>>> 700 Seco Road
> > >>>> Monroeville, PA 15146
> > >>>> 412-858-6264
> > >>>> rdudek@xxxxxxxxxxxxxxx
> > >>>> www.compunetics.com =3D20
> > >>>>
> > >>>> To see where no one notices the contrast of white on white is 
> =
> > >>>> 
> > >> an=3D20=20
> > >> 
> > >>>> indispensable virtue of infinite potential.
> > >>>>
> > >>>> =3D20
> > >>>>
> > >>>>
> > >>>>
> > >>>> 
> ------------------------------------------------------------------
> > >>>> To unsubscribe from si-list:
> > >>>> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the=20
> > >>>> 
> > >>> Subject field
> > >>> 
> > >>>> or to administer your membership from a web page, go to:
> > >>>> http://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: =3D20
> > >>>> http://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
> > >>>> =3D20
> > >>>> 
> > >>> =20
> > >>> =20
> > >>> 
> ------------------------------------------------------------------
> > >>> To unsubscribe from si-list:
> > >>> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the 
> Subject field
> > >>> =20
> > >>> or to administer your membership from a web page, go to:
> > >>> http://www.freelists.org/webpage/si-list
> > >>> =20
> > >>> For help:
> > >>> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
> > >>> =20
> > >>> =20
> > >>> List technical documents are available at:
> > >>> http://www.si-list.net
> > >>> =20
> > >>> List archives are viewable at: =3D20
> > >>> http://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
> > >>> =3D20
> > >>> 
> ------------------------------------------------------------------
> > >>> To unsubscribe from si-list:
> > >>> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the 
> Subject field
> > >>> =20
> > >>> or to administer your membership from a web page, go to:
> > >>> http://www.freelists.org/webpage/si-list
> > >>> =20
> > >>> For help:
> > >>> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
> > >>> =20
> > >>> =20
> > >>> List technical documents are available at:
> > >>> http://www.si-list.net
> > >>> =20
> > >>> List archives are viewable at: =20
> > >>> http://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
> > >>> =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:
> > >> http://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: 
> > >> http://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
> > >> 
> > >> 
> > >
> > >
> > > 
> ------------------------------------------------------------------
> > > 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:
> > > http://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: 
> > > http://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
> > > 
> > >
> > >
> > >
> > > 
> >
> >
> > -- 
> > Steve Weir
> > Teraspeed Consulting Group LLC 
> > 121 North River Drive 
> > Narragansett, RI 02882 
> >
> > California office
> > (408) 884-3985 Business
> > (707) 780-1951 Fax
> >
> > Main office
> > (401) 284-1827 Business 
> > (401) 284-1840 Fax 
> >
> > Oregon office
> > (503) 430-1065 Business
> > (503) 430-1285 Fax
> >
> > http://www.teraspeed.com
> > This e-mail contains proprietary and confidential intellectual 
> property
> of Teraspeed Consulting Group LLC
> >
>
-------------------------------------------------------------------------
---
> --------------------------
> > Teraspeed(R) is the registered service mark of Teraspeed 
> Consulting Group
> LLC
> 
> 
> ------------------------------------------------------------------
> 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:
> http://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: 
> http://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
> 
> 
> 
> 
>  __________________________________________________
> Do You Yahoo!?
> Tired of spam?  Yahoo! Mail has the best spam protection around 
> http://mail.yahoo.com 
> 
> ------------------------------------------------------------------
> 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:
> http://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:     
>                 http://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
>   
> 
> 
> 
------------------------------------------------------------------
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:
http://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:     
                http://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: