Try this http://indy2.automata.com/tools/imped/imped-ems.unsafe.html Jeff Cole Battelle PNNL Scientific Engineering Associate (509) 375 - 2758 PH (509) 372 - 4725 Fax [log in to unmask] -----Original Message----- From: Daniel A. Doherty [SMTP:[log in to unmask]] Sent: Thursday, February 18, 1999 11:27 AM To: [log in to unmask] Subject: [DC] Embedded Microstrip Does anyone happen to know the CORRECT formula for the capacitance of an embedded micstrip? The one contained in -D-317A pg. 23 cannot be right as the natural log of a negative number is not defined... 317A states: C=(1/(H+t))*ln(1-(.6987*(E+1.41)/sqrtE)) Daniel A. Doherty North Coast Design 6341 Applewood Ln. Williamsburg, MI 49690-9725 V 616.267.9717 F 616.267.9718 ################################################################ DesignerCouncil E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE DesignerCouncil <your full name> To unsubscribe: SIGNOFF DesignerCouncil ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################ ################################################################ DesignerCouncil E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE DesignerCouncil <your full name> To unsubscribe: SIGNOFF DesignerCouncil ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################