Just to explain the manufacturing codes of the 2 mentioned microwave base materials: Taconic's RF-35 is a
ceramic filled PTFE/glass base material with a DK of 3.5. Rogers' 4003 is a ceramic filled thermoset
resin/glass base material with a DK of 3.38.

RF-35 is typically used in applications up to approx. 10 GHz. It is difficult to advise from which frequency
on one should use an RF/microwave base material. It really depends on your design, tolerances, etc. Take the
loss factor for example: The loss factor of RF-35 is 0.0018 at 1.9 GHz, and around 0.0012 at 500 MHz (I  have
no accurate data for such a low frequency, because typically we start measuring Df above 1 GHz), whereas the
one of FR4 is about 0.015 at 500 MHz - ten times higher!

Or look at water absorption. Max. permissible water absorption of FR4 is 0.35 %, whereas PTFE/glass base
material absorb less than 0.02 %.

TechNet is not meant for advertising products. For this reason I don't want to compare more data on this
reply. I would have to ask you to visit the Taconic web site at http://www.taconic-add.com for more product
data.

There are pcb shops specialising in processing microwave base materials. But in general they are processed in
in similar steps than FR4. The main difference is hole wall processing, where PTFE base material require a
plasma etch hole wall preparation compared to permanganate treatment for FR4. Any board shop that manufactures
flexible or rigid/flex pcbs should therefore also be able to manufacture RF/microwave boards. Please contact
Taconic off-line if you need recommendations.

regards

Manfred Huschka
Taconic Advanced Dielectric Division
[log in to unmask]


--- On Fri, 29 Jan 1999 09:44:27 -0400  Yvon Hache <[log in to unmask]> wrote:
Hi everybody,
I have been following this RF Material stuff but I don't understand anything about RF35 and Roger 4003
manufacturing codes.  I am a design engineer and the last design we are working on uses RF at 418MHz.  Does
standard FR4 material will work fine?  Is there any consideration I should take care of when contacting a
board manufacturer?

thanks


Yvon Hache
Design Engineer
Concept + Inc.

Tel: 506-863-2467
Fax: 506-858-4075
email: [log in to unmask]
web: www.concept-plus.com

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################


--------------------------------------------------------
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: http:\\www.taconic-add.com
Date: 01/30/99
Time: 09:42:56

This message was sent by Z-Mail Pro - from NetManage
NetManage - delivers Standards Based IntraNet Solutions
--------------------------------------------------------

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################