Hi Saoer, There are generally two ways to include S-parameter data in a SPICE simulation: 1. Directly using an S-parameter primitive 2. Indirectly, by using a separate tool to create an equivalent network = of (passive) circuit elements which can be included as a sub-cicuit in the SPICE simulation. Many of the popular SPICE simulators have options to enforce passivity = and causality in the evaluation of their S-parameter primitives. I have personal experience with this feature in the simulators from = Mentor Graphics, Agilent and Ansoft.=20 My appolgies to the vendors of other popular tools, but I do not have = the personal experience to talk about the availability of this feature in = their simulators. As Antonio says, many of the separate tools that create equivalent SPICE sub-circuits from S-parameter descriptions also have these options. The full wave solvers from quite a few popular vendors create models = that have causality and passivity issues. This problem can be made worse if the model was generated for a smaller frequency range than will be used for simulation. S-parameter models created from measurement can also suffer from the = same problems due to small errors in the measurement process. If you are interested in more information, papers from Mentor Graphics (DesignCon 2006), Ansoft (IBIS China 2007) and Agilent (DesignCon 2008) = are available. (Again my appologies to the authors of other papers on the subject, these are a few that I saw in person). I hope this helps Ian Dodd SI Consultant -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] = On Behalf Of Antonio Ciccomancini Scogna Sent: Monday, June 02, 2008 6:53 AM To: saoer.sinaga@xxxxxxxxx; si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: S-par to Spice Hi Saoer, Typically all 3D EM tools have the possibility to enforce passivity = thought generation of a SPICE model: for instance MOR (model order reduction) technique. With regarding to free tools in order to achieve this task you can take = a look to http://www.emc.polito.it/ Best regards, Antonio -----Original Message----- From: saoer.sinaga@xxxxxxxxx [mailto:saoer.sinaga@xxxxxxxxx] Sent: Monday, June 02, 2008 4:02 AM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] S-par to Spice Dear all, As you all might know, the S-parameter produced by HFSS is not always passive, especially when you extrapolate to DC. Is there any tool that can generate a passive spice file (spectre compatible) out of a non-passive S-par? Preferably a freeware that I can = use immediately. many thanks, Saoer Sinaga NXP Semiconductors. ------------------------------------------------------------------ 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 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 -- HTML Attachment decoded to text by Ecartis -- -- File: ALTERNATIVE.HTM =20 Hi Saoer,=20 =20 Typically all 3D EM tools have the possibility to enforce passivity = thought generation of a SPICE model: for instance MOR (model order reduction) technique.=20 With regarding to free tools in order to achieve this task you can take = a look to http://www.emc.polito.it/[1]=20 =20 Best regards, Antonio=20 =20 =20 =20 =20 =20 =20 -----Original Message----- From: saoer.sinaga@xxxxxxxxx [mailto:saoer.sinaga@xxxxxxxxx]=20 Sent: Monday, June 02, 2008 4:02 AM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] S-par to Spice=20 =20 Dear all,=20 As you all might know, the S-parameter produced by HFSS is not always=20 passive, especially when you extrapolate to DC.=20 Is there any tool that can generate a passive spice file (spectre=20 compatible) out of a non-passive S-par? Preferably a freeware that I can = use immediately.=20 =20 many thanks,=20 Saoer Sinaga=20 NXP Semiconductors.=20 =20 =20 ------------------------------------------------------------------=20 To unsubscribe from si-list:=20 si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field=20 =20 or to administer your membership from a web page, go to:=20 //www.freelists.org/webpage/si-list=20 =20 For help:=20 si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field=20 =20 =20 List technical documents are available at:=20 http://www.si-list.net=20 =20 List archives are viewable at: =20 //www.freelists.org/archives/si-list=20 or at our remote archives:=20 http://groups.yahoo.com/group/si-list/messages=20 Old (prior to June 6, 2001) list archives are viewable at:=20 http://www.qsl.net/wb6tpu=20 =20 =20 --- Links --- 1 http://www.emc.polito.it/ ------------------------------------------------------------------ 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: =20 //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 =20 ------------------------------------------------------------------ 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 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