Those pesky SMA launches strike again! bdempsey85 wrote: >All, > >I thought I would post my results from today's experiment. Yesterday >the traffic coming back from the server and privately was to examine the >launch -- i.e. the connectors. > >I cut off the edges of the PCB and mounted and end-launch SMAs to the >board. Even as poor as my connection is I have max loss of 1dB on S21! > >So this tells me (and any listeners) that the connector can (and did) >kill! > >Thanks to all who responded to my first post. > >Regards, >Bill > > > >>-----Original Message----- >>From: si-list-bounce@xxxxxxxxxxxxx >> >> >[mailto:si-list-bounce@xxxxxxxxxxxxx] > > >>On Behalf Of bdempsey85 >>Sent: Tuesday, March 09, 2004 10:06 AM >>To: 'Scott McMorrow'; si-list@xxxxxxxxxxxxx >>Subject: [SI-LIST] Re: uStrip question >> >>I'm off to do that in just a few minutes. Some quick lab work last >>night was showing that our end-launched designs are working.. >> >> >>The TDR analysis will hopefully show that the design-to-impedance >>numbers are right on. >> >> >> >> >> >>Bill >> >>-----Original Message----- >>From: Scott McMorrow [mailto:scott@xxxxxxxxxxxxx] >>Sent: Tuesday, March 09, 2004 8:22 AM >>To: bdempsey85@xxxxxxxxxxx >>Subject: Re: [SI-LIST] Re: uStrip question >> >> >> >>Bill >> >>Have you done a TDR of the traces to see what your impedance is, and >> >> >if > > >>there are any launch anomolies off the SMA's/ >> >>scott >> >> >>Bill Dempsey wrote: >> >> >> >>Tom, >> >>We have a set of rt angle calibration connectors that we use to cal >> >> >out > > >>the >>coax + connector effect. These same "style" connectors (diff vendor) >>are >>used as the souce/load connection point to the PCB. They are of >> >> >course > > >>soldered to the PCB -- that is to say they are not pressed or held in >>place. >> >>Did I answer your question? >> >>One item of note -- the Smith chart is showing a mostly inductive >> >> >tline. > > >>As part of this evaluation I built 3 tlines per board: one >>straight-thru, >>one with five 0402 custom sized packages with the terminals shorted, >> >> >and > > >>one >>with five 0603 packages... >> >>Interestingly the the tline with the 0603 pads (additional >> >> >capacitance) > > >>has >>much better performance (about 2.3dB loss vs. 6.5dB). >> >>Bill >> >> >>----- Original Message ----- >>From: "Tom Dagostino" <mailto:tom@xxxxxxxxxxxxx> <tom@xxxxxxxxxxxxx> >>To: <mailto:bdempsey85@xxxxxxxxxxx> <bdempsey85@xxxxxxxxxxx>; >><mailto:si-list@xxxxxxxxxxxxx> <si-list@xxxxxxxxxxxxx> >>Sent: Monday, March 08, 2004 10:26 PM >>Subject: [SI-LIST] Re: uStrip question - repost >> >> >> >> >>What you did not mention in your note may be the problem you are >>having.. >>How did you connect your VNA to the test articles? How clean was the >>launch? It is easy to get large reflections from poorly designed >>launches >>that will affect S21 >> >> >>Tom Dagostino >>Teraspeed Consulting Group LLC >>Device Modeling Division >>13610 SW Harness Lane >>Beaverton, OR 97008 >>503-430-1065 >>tom@xxxxxxxxxxxxx <mailto:tom@xxxxxxxxxxxxx> >> >> ><mailto:tom@xxxxxxxxxxxxx> > > >>Teraspeed Consulting Group LLC >>2926 SE Yamhill St. >>Portland, OR 97214 >>http://www.teraspeed.com >> >> >> >>-----Original Message----- >>From: si-list-bounce@xxxxxxxxxxxxx >>[mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Bill Dempsey >>Sent: Monday, March 08, 2004 7:57 PM >>To: bdempsey85@xxxxxxxxxxx; si-list@xxxxxxxxxxxxx >>Subject: [SI-LIST] uStrip question - repost >> >> >>--sorry for the repost but the server is adding junk to the message >> >> >that > > >>made it unclear to read -- >> >>I recently built 3 different uStrip construction testboards and was >>surprised by the results: it didn't work! >> >>I built two boards as trace over copper with soldermask and one board >>as a co-planar waveguide. I constructed the geometries of the boards >> >> >by > > >>following the results of some "freebie" tools out there. >> >>After the boards were built I connected them to an HP network analyzer >>(I calibrated out the cables/cons) to look at S21 response. What I >>found was surprising. The S21 was extremely poor: approx 6.5dB loss >>over 4". This just does not compare to the results of the tools I have >>access to. I expected about 1.2 - 1.5 dB of loss at this frequency. >> >>Has anyone else out there had some bad experiences with uStrip @ >>2.5GHz? What tools are you using? How are you correlating your >>tool's results to real-world? >> >>The construction of the three boards was as follows: >> >>Board 1: 12 mil trace, 1/2 oz foil with 1 oz plating, 8 mil to gnd >>(three >>sheets of 1080 prepreg), 1oz copper gnd >> >>Board 2: (CPW): 8 mil trace, 8 mils to gnd (again, 3 sheets of 1080 >>prepreg), 6 mil to gnd return on signal layer, same >> >> >plating/thicknesses > > >>Board 3: 4.75 mil trace, ~2.83 mils to gnd (one sheet of 1080 >> >> >prepreg), > > >>1/2 oz foil, 1oz plating, 1oz copper gnd >> >>Regards, >> >>Bill >> >>------------------------------------------------------------------ >>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.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 >> >> >>------------------------------------------------------------------ >>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.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 >> >> >> >> >> >>------------------------------------------------------------------ >>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.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 >> >> >> >> >> >> >> >> >>-- >>Scott McMorrow >>Teraspeed Consulting Group LLC >>2926 SE Yamhill St. >>Portland, OR 97214 >>(503) 239-5536 >>http://www.teraspeed.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: >>//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.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 >> >> >> > >------------------------------------------------------------------ >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.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 > > > > -- Scott McMorrow Teraspeed Consulting Group LLC 2926 SE Yamhill St. Portland, OR 97214 (503) 239-5536 http://www.teraspeed.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: //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.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