Fred,

although I am working for a PTFE/woven glass fabric manufacturer, I can tell you that based on many years of
experience in manufacturing FR4, BT/Epoxy, Polyimide, PTFE, etc. base materials, 400 MHz is still a good
frequency for FR4 - depending on tolerances.

Some design engineers use FR4 up to more than 1 GHz, whereas other ones use PTFE/woven glass laminates from
even as low as 200 MHz on.

Regards

Manfred Huschka
Taconic

--- On Thu, 21 May 1998 08:25:09 -0700  Fred Watt <[log in to unmask]> wrote:
        Has anybody had any problems with FR-4 at 100 to 200 MHz?  I have several boards from several
fabrication shops in which the signal loses amplitude above 80-100 MHz.  The boards are controlled impedance
(50 Ohms) with 5 mil traces and 5 mil dielectrics.  The traces are about 6.5" long.
        I would appreciate any comments on this subject.  The supplier of the material says that FR-4 should
be good to 400 MHz.

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---------------End of Original Message-----------------

--------------------------------------------------------
Name: Manfred Huschka
Taconic Advanced Dielectric Division, Lynn Industrial Park, Mullingar,
Co. Westmeath, Republic of Ireland
Office: PF 1275, D-51676 Wipperfuerth, Germany
        Tel.: +49 2267 888004
        Fax:  +49 2267 888005
E-mail: Manfred Huschka <[log in to unmask]>
Web: www.taconic-add.com
Date: 05/22/98
Time: 18:17:36

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