Try:- www.ultracad.com/articles.htm <http://www.ultracad.com/articles.htm> and www.polarinstruments.com <http://www.polarinstruments.com> Geoff Layhe -----Original Message----- From: Benjamin Zhu [mailto:[log in to unmask]] Sent: 23 May 2001 07:31 To: [log in to unmask] Subject: [TN] Controlled Impedance Hi All, Is there anybody who can tell me some information about controlled impedance, like: * Documents * Website where I can find information about controlled impedance * You kindly comments about controlled impedance (Differential & Coplanar structure preferred) Thank you for your kindly help. Best regards, Benjamin Zhu Private & Confidential: This e-mail message is confidential and is intended solely for the person or organisation to whom it is addressed. If the message is received by anyone other than the addressee please return the message to the sender by replying to it and then delete the message from your computer.