careful of ED-130 this material is no longer being made by Allied 
     Signal and is getting tuffer and tuffer to get.  We have found that 
     FR404 gives us a very similar DK to ED130.  The stack up of the layer 
     is very important because a change in the stack up can change your DK.


______________________________ Reply Separator _________________________________
Subject: AW: Dielectric Constant-1 -4 gigaHz
Author:  [log in to unmask] at _internetcc
Date:    12/5/96 12:57 PM


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]
     
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