I just had a discussion with engineer about our RF project. He would really like to
see a lower-loss material. What is the characteristic dielectric constant (DC) for
Getek and Nelco 4000-13? I haven't used/specified these before. Or if there are
other common materials, excluding polyimide or teflon, that I could suggest. The
goal is a DC less than 4.

TIA

Scott
IDS

Gfranck wrote:

> Your RF guy might be correct.
> For RF applications using Epoxy blended materials I usually specify the
> laminate.  Two that come to mind are Getek, and Nelco 4000-13.  There are many
> others which are blended for high-speed, low-loss operations.  There actually is
> a wide range of materials which can qualify as FR-4, with a wide range of
> electrical properties at 'higher' frequencies.
>
> Even with the same resin, the dielectric constant for them material on 7628
> glass might be 4.6, and on 106 glass might 4.1.  Why?  because the resin %
> changes from 40% to 75% and the glass has a dielectric constant of over 6, and
> the resin has a constant of around 3.
>
> George Franck
> "My Opinions are just that"
>
> Ron Luman wrote:
>
> > I am having a problem with the RF engineer saying the board material
> > (vendor) is the problem with his circuit not working. In every formula I
> > have looked at the dielectric constant of FR4 is the same.
> > My boards are .062 thick FR4 Tg 130. no soldermask no silkscreen.
> > Can someone out there explain to me what the differences can be between two
> > vendors when they are both using the same process notes I supply to make the
> > boards??
> > And how this might effect the RF circuit?
> > Thank You
> >
> > Ronny Luman C.I.D.
> > SERCEL INC.
> > (918) 621-5725
> > [log in to unmask]
> >