Thanks for the replies. After reviewing my problem again with Tr(rise time) around 100ps (Er=3D4.3), 1mm~2mm line should act as a lumped capacitor based on the formula Tr/(5*To)>length [eq.(6.32),pp239,Bakoglu]. For my case, 100ps/(5*69ps/cm) =3D 20/69cm > length=3D1mm~2mm. Thus I added only a lumped capacitor to one line like this. in1 --------------- out1 --capacitor- connected to gnd in2 --------------- out2 in3 --------------- out3 |<----10cm---->| |<--1mm-->| Should I also include an inductor together with a lumped capacitor? If the extra length I am considering were greater than 20/69cm, I think I should follow the Ihsan's advice. Thanks, Yongjin --- In si-list@xxxxxxxxxxxxxxx, "Ihsan Erdin" <erdinih@...> wrote: > > The question implies that the mutual coupling between the lines be included > otherwise the solution is trivial. If the length difference is short > cascading a w-element is not a good solution. Indeed the w-element for > electrically short lines should be avoided at all times. A quick and dirty > way is to make a ladder circuit or use a U-element (if anybody can remember > that...) to account for the length difference. > Regards > > Ihsan > > > On 3/29/06, YongJin CHOI <yc2158@...> wrote: > > > > Dear SI members, > > I am looking for a simple simulation method to get a > > rough idea if one or two of the four traces is a > > little bit longer like 1~2mm. The transmission line > > models I am having are W-model from Hspice field > > solver(2-D) and S-parameter model from HFSS. I can use > > Hspice or Spectre depending on the simplicity. > > Any comments would be appreciated. > > Thanks, > > > > Yongjin CHOI > > > > __________________________________________________ > > 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@... 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@... 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@... 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@... 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