We could achieve lower crosstalk by using dielectric with lower permittivity, while keeping *Z0* as a constant. I'm new in SI, my understanding about this question is: If we use dielectric with lower permittivity while keeping *Z0* as a constant. We need to reduce *h *to maintain a constant *C*, because *C*= *epsilon***w* /*h*, and *Z0*=1/*vp*/*C*. Since *Z0* = sqrt(*L/C*), to keep* Z0* as a constant, the stripe line need to adjust it?s current distribution to maintain a constant *L*. Considering the loop area decrease because *h* is reduced, the current distribution should be more tighter to maintain a constant *L*. Finally the tighter current distribution on the returning pass results in the reduction of the cross talk. Are these correct? I will appreciate your help Best Regards ------------------------------------------------------------------ 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