Hi Tom, in my opinion the portfolio of an SI engineer working at gigabit application should contain 2 kind of tools. First a 3d full wave EM solver should be used, in pre-layout analysis, to fix necessary layout constraint to be used to obtain a clean design. It should be clear that decision about via, differential via , cut in gnd planes should not be taken be without the help of a tool . A 3D solver will help you, in an easy way, to find the best comprise about strategic problem. Last but not least a 3D solver can be efficient to analyse power Delivering System,decide where to place decap capacitor and theyr values... At the moment I am using CST Microwave Studio, being a time domain solver, it could be very useful for signal integrity problem A 2D EM solver could also be used to optimize layer stack-up, spacing and width of traces, material...and so on ( you could find some tools very useful on the web) Second, a post-layout tool would be necessary when the layout will be complete to correct problem introduced during the routing especially if one uses automatic routing. A typical post-layout tool like the one offered by company such as Zuken could be a valid help to find potential SI problem in a complex board and will allow you to perform efficient time-domain analyisis A last consideration should be done: these tools need to be introduced in your design flow and they will have an impact on it. In my opinion both pre-layout and post-layout analysis could dramatically improve the "quality" of design flow and produce a drastic reduction of the time you, actually, spend debugging your board but you would need to be careful in tuning the exchange of information among your design flow Hope this could help Giancarlo tom_cip_11551 ha scritto: > Hi, > > At present, I work for a small company that does gigabit design, > pretty much by experiment. If we do not make our return loss > specification, we take some copper away from the ground layer, or do > something else, until we do make it. We may turn the board a few > times but that is the way it goes. > > I have done a number evauations of programs that do EM analysis, > such as AWR Microwave Office, CST Microwave Studio and Sonnet EM > Suite. > > I would like to know if there is an opinion in the group concerning > any other programs that are generally used. For example, I have read > some data about Cadence Specctraquest. Specctraquest, however, > appears to be more model based (pspice) than EM based. > > Before I make a proposal to management for capital equipment, I > would like to get more opinions for the SI group. > > The main challenge that we have, is the mating of high speed > connectors to the PCB. Sometimes we can get spice models of the > connector, by itself, but that does not do us much good concerning > the mating interface of the PCB pad to the connector pin. > > Thank You > Tom > > > > > > > > ------------------------------------------------------------------ > 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 > > > > > ------------------------------------------------------------------ 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