Unless you specify the dielectric constant on the drawing, FR-4 has a wide
range compared to some of the microwave materials. If it's not specified, it
can be anywhere in the range and it still meets your print.

> -----Original Message-----
> From: Ron Luman [SMTP:[log in to unmask]]
> Sent: Monday, September 27, 1999 11:01 AM
> To:   [log in to unmask]
> Subject:      [DC] RF boards
>
> 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]