Vijay, If you calculate the capacitance per unit length C with all dielectrics present. And calculate the capacitance per unit length Co with all dielectrics set to air. c is speed of light in vacuum. Then Z = 1 / (c x sqrt(C x Co)) It does not matter what you call it. There are some shareware FEM programs on the WEB that will let you look at arbitrary geometries. www.quickfield.com www.pdesolutions.com Both of these limit the number of nodes. Use symmetry to get more nodes applied to your problem. The full version of FlexPDE is less than $500. Dan Dan Swanson EMAIL: d.swanson@xxxxxxxx Bartley RF Systems, Inc. TEL: 978-834-4085 37 South Hunt Road FAX: 978-388-7077 Amesbury, MA 01913 On Thursday, September 20, 2001 8:21 PM, Vijay Varadarajan [SMTP:Vijay.Varadarajan@xxxxxxx] wrote: > Hi All! > Consider a EM structure with 4 layers of dielectric. > layer 1 air > layer 2 dielectric > layer 3 dielectric > layer 4 dielectric > top and botton are grounded. if i draw a rectangular conductor in layer 3(say) how do i calculate the characteristic impedane for the port termination. do i consider it as a stripling or a microstrip. > i will be gald if anyone could anwer my question. > - vijay > > ------------------------------------------------------------------ > 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 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 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