[SI-LIST] Re: Microstrip line loss on Rogers 4350
- From: Ming Tsai <ming.tsai@xxxxxxxxxx>
- To: jaudet@xxxxxxxxxx
- Date: Mon, 21 Mar 2005 10:44:24 -0800
Hi Jean,
I did not take 'good' care of my test board. I did leave it in the lab. Did
not think of moisture and temp issues. But it is really the case, how could
the board go to production or installed in the fields?
Hopefully I could find the cause in the design of fabrication, otherwise, it
would be a really BIG worry for me...
Thanks!
Ming
jaudet@xxxxxxxxxx wrote:
> Also moisture absortion level produce additional insertion loss.
>
> So if the parts or board sit on your desk for a couple weeks, you will get
> a moisture level saturation for the specific temp/humidity condition of
> your envronement. As an example if you mesure a dry part versus a part
> expose at 35C and 85% RH, this will affect the insertion loss perfomance
> and may be significant.
>
> The SM and the dielectric absorb at different level the humidity....
>
> P.S. also by increasing the temperature of the board (like 80C) you will
> get also a significant additional insertion loss (depend on your material
> used)
>
> Jean Audet
> Electrical Analysis
> STG / World Wide Packaging & Test
> Organic and Ceramic Packages
> IBM Bromont
> Tel: 450-534-6317, tie line: 552-6317
> E-mail: jaudet@xxxxxxxxxx
>
>
> "Loyer, Jeff"
> <jeff.loyer@intel
> .com> To
> Sent by: "steve weir" <weirsi@xxxxxxxxxx>,
> si-list-bounce@fr <ming.tsai@xxxxxxxxxx>,
> eelists.org <si-list@xxxxxxxxxxxxx>
> cc
>
> 03/21/2005 12:19 Subject
> PM [SI-LIST] Re: Microstrip line loss
> on Rogers 4350
>
> Please respond to
> jeff.loyer
>
>
>
>
> Could be - my experience with 22mil traces is limited to zero.
>
> I'd be interested to know what the final finding is.=20
>
> Jeff Loyer
>
> -----Original Message-----
> From: steve weir [mailto:weirsi@xxxxxxxxxx]=20
> Sent: Monday, March 21, 2005 8:43 AM
> To: Loyer, Jeff; ming.tsai@xxxxxxxxxx; si-list@xxxxxxxxxxxxx
> Subject: Re: [SI-LIST] Re: Microstrip line loss on Rogers 4350
>
> Jeff, I don't think a poor model of the trace shape is at play here.
> Ming=20
> has a very wide trace, and he sanded the SM off the top. There will
> still=20
> be some fringing through SM adjacent to the traces, but I would start
> with=20
> getting the calibration right. Scott has speculated that Ming might be=20
> running into a resonance issue with his SMA launches.
>
> Steve.
> At 08:15 AM 3/21/2005 -0800, Loyer, Jeff wrote:
> >I had similar results on FR4 when I played around with several
> >configurations (single-ended and differential microstrip, single-ended
> >asymmetric stripline, and differential symmetric stripline), trying to
> >correlate different tools to actual measurements. I could get good
> >broadband correlation for all but the single-ended microstrip (and I
> did
> >have well setup TRL structures for all). For single-ended microstrip,
> I
> >couldn't get good correlation at all frequencies with any tool (though
> >this wasn't an in-depth study). I suspect that, for this case, the
> >trace geometries are complex enough that all the subtleties must be
> >properly represented. For instance, neither a simple rectangle nor
> >trapezoid is sufficient - the plating process makes the trace appear as
> >more of a "mushroom". This complex shape might have significant effect
> >on cross sectional area, and how the fields surround the trace (how
> much
> >energy is in dielectric vs. air). I think you might have to
> >cross-section your traces to determine their actual complex geometry,
> or
> >take a best guess, based on info. from your fab vendor.
> >
> >I'm surprised that removing the soldermask didn't have any effect.
> >While I haven't done that on actual boards, simulations show it does
> >have a significant effect. And, I've added soldermask (putting a layer
> >of Kapton tape over a trace), and seen significant effects.
> >
> >My 2 cents.
> >
> >Jeff Loyer
> >
> >-----Original Message-----
> >From: si-list-bounce@xxxxxxxxxxxxx
> [mailto:si-list-bounce@xxxxxxxxxxxxx]
> >On Behalf Of Ming Tsai
> >Sent: Friday, March 18, 2005 6:08 PM
> >To: si-list@xxxxxxxxxxxxx
> >Subject: [SI-LIST] Microstrip line loss on Rogers 4350
> >
> >Hi All,
> >
> >I am studying the microstrip line loss on 10 mil Rogers 4350 (Er =3D3D =
> =3D
> >3.48,
> >loss tangent =3D3D 0.004 @ 10 GHz). The trace width is 22 mils, with =
> half
> =3D
> >oz
> >copper. From some transmission line calculator I expect to see 0.25dB
> >/inch loss @ 10 GHz. However I measured under network analyzer and I
> got
> >the loss up to 0.5dB/inch @ 10 GHz.
> >
> >I did not have well-setup TRL calibration on board, but I took 3
> >separate measurements from 3", 5" and 7.5" long microstrip lines, and
> >estimated the delta to get 0.5dB/in loss. So I assume the edge-mounted
> >SMA connector is not a factor. Also checked under TDR I saw 48 ohms of
> >line impedance, which is within the spec. I also scratched out the
> >solder mask which did not have any effect. I used full-wave tool to
> >verify the radiation as well as skin effect, but no surprise the
> >simulation showed that I should get about 0.25dB/in loss.
> >
> >Does anyone have similar experience or any suggestion? Thanks!
> >
> >Regards,
> >
> >Ming
> >--
> >Ming. Tsai
> >Staff Hardware Development Engineer
> >Product Technology - Hardware Design Group
> >XILINX
> >
> >
> >
> >------------------------------------------------------------------
> >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: =3D20
> > //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
> >
> >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:
> > //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
> >
>
> The weirsp@xxxxxxxxxx e-mail address will terminate March 31, 2005.
> Please update your address book with weirsi@xxxxxxxxxx
>
> ------------------------------------------------------------------
> 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:
> //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
--
Ming J. Tsai, Ph.D.
Staff Hardware Development Engineer
Product Technology - Hardware Design Group
XILINX
Telephone: 408-626-6260
E-Mail: ming.tsai@xxxxxxxxxx
------------------------------------------------------------------
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:
//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:
