Steve, The trace width is 50um, so according to your calculations, L is roughly 760nH/m. I am getting 611nH/m from Q3D. However, Q2D and mathematical equations give much lower L. Thanks, -Adnan -----Original Message----- From: steve weir [mailto:weirsi@xxxxxxxxxx] Sent: Friday, May 20, 2011 12:00 PM To: Yassin, Adnan Cc: si-list@xxxxxxxxxxxxx Subject: Re: [SI-LIST] Ansoft Q2D vs. Q3D It appears that the Q3D model is inferring mutual coupling to some structure. Perhaps your bounding box is too small. As a sanity check, in rough numbers, for a 30um height above the plane we should expect about 38pH/square which works out to about 2500nH/m at 15um width. That is way-off from either of the inductance/length figures you obtained. So, something looks fundamentally wrong. Steve. On 5/20/2011 11:27 AM, Yassin, Adnan wrote: > Hi Folks, > I have a question regarding extraction data using Ansoft Q2D vs. Q3D. I have > a simple model consists of a copper trace, 15um wide& 15um high. It is 30um > above a reference ground. The dielectric constant of the material between the > trace and the GND plane is 3.9. RLCG is extracted at 1.0GHz. The "RL" data I > get from Q2D is different than Q3D for the same model (data is below). Can > someone explain why the difference? The Q3D model is generated from Q2D model > using "Create 3D Design" command in Ansoft. What do I need to do when > generating 3D design from 2D design before extracting RLCG? > > G(mS/m) C(pF/m) R(ohm/m) L(nH/m) > Q2D Design 6.81 108.0 123.85 304.14 > Q3D Design 6.63 108.2 82.17 611.0 > > Thanks, > -Adnan > ------------------------------------------------------------------ > 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.net > > List archives are viewable at: > //www.freelists.org/archives/si-list > > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > > > -- Steve Weir IPBLOX, LLC 150 N. Center St. #211 Reno, NV 89501 www.ipblox.com (775) 299-4236 Business (866) 675-4630 Toll-free (707) 780-1951 Fax ------------------------------------------------------------------ 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.net List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu