The dielectric constant of 0.71 mm epoxy/glass laminate is 4.8 at 1 Mhz, 4.6 at 1 GHz and 4.57 at 8.5 GHz. Due to the nature of the base material, a composition of E-glass (DK of 6.6 at 1 MHz) and epoxy resin (DK of 3.6 - 3.7 at 1 MHz), and a retained resin content of the laminate of approx. 40 %, the value will not change even when using a different laminate from another supplier. We have measured DK values for ED130 (difunctional epoxy, min Tg 130 Deg C) FR404 (multifunctional epoxy, min Tg 150 Deg C) and found no difference within normal measuring tolerances. Comparing the behaviour of FR4 to that of BT-Epoxy (e.g. G200) it has to be noted that the slope of DK drop at higher frequencies is not as steep with BT-Epoxy. Regards Manfred Huschka AlliedSignal Laminate Systems Europe ---------- Von: [log in to unmask] An: [log in to unmask] Betreff: Dielectric Constant-1 -4 gigaHz Datum: Donnerstag, 5. Dezember 1996 00:49 Microsoft Mail v3.0 (MAPI 1.0 Transport) IPM.Microsoft Mail.Note From: [log in to unmask] To: [log in to unmask] Subject: Dielectric Constant-1 -4 gigaHz Date: 1996-12-05 00:49 Priority: 3 Message ID: B99511B7194ED011B4CF00805FD4C991 ----------------------------------------------------------------------- ----- -- hi, one of my customers have built a 4 layers board as follows: ____________________________18 MIC COOPER (1/2 oz) ======================== ======================== 3 X 7628 ======================== ---------vcc-------35 mic cooper (1 oz) 0.711mm CORE ----------gnd-------35 mic cooper SAME AS ABOVE with multifunctional resin type materials, it's tg is 140 c. the end-user of this board have not specified any controlled impedance tracks , BUT some signals do carry 0.7 giga to up to 4 giga !!! could someone advise what is the dk of the epoxy at those rates, should other materials be used then std. epoxy resins (fr4 -gfn) any comment would be appreciated. Yisrael Leshman Octava Marketing zichron-yaakov ISRAEL [log in to unmask] ************************************************************************ *** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * ************************************************************************ *** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * ************************************************************************ *** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ************************************************************************ *** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************