Thanks for all of replies.Specially for bradb and shlepnev's patience,you are so nice, also for ken's honest and direct advice. First, i am not using a pirated copy of HFSS. i ask help for local FAE. but he always gives me wrong answers. he seems to be less knowledged in EM than me. So i resort to SI-LIST Yes, Ken,you are right, i only have undergraduate level Emag. But it can not prevent me from learning EM without a education background. ------------------------------------------------------------------ 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