TECHNET Archives

May 1998

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
"Arturo J. Aguayo" <[log in to unmask]>
Reply To:
Date:
Sun, 24 May 1998 08:02:20 -0700
Content-Type:
text/plain
Parts/Attachments:
text/plain (58 lines)
Hi to All,

Been following this long string of emails and just wanted to add a
comment or two from an RF/microwave point of view (which from some of
the comments I think probably already know). I also work for a high
frequency material supplier and have come across designs that use FR4 at
2 GHz and PTFE materials at 880 MHz. The case is that each application
is different and there is no set limit at which one type of material
ends and the other starts. One trend we have seen is that if the
application is digital, the switch to high performance materials is
sooner. The reason is that a square signal is made of of a series of
sine waves with a fundamental and a series of harmonics. When the
dielectric constant of a material changes vs frequency (which FR4 does),
the speed of each components is different. Faster rise times create the
need for higher level harmonics and these can start getting quite high
into the RF/microwave range (where dielectric losses are quite
critical). Hope this helps.

Art Aguayo, Technical Support Manager
Rogers Corporation
[log in to unmask]


Fred Watt wrote:
>
>         Thank you all for your inputs and thoughts on the subject of Frequency performance of FR-4 material.  This is an interesting Discussion.  Hope it continues.
>
>         The Rise time of 175 psec was degraded to 375 psec.
>
> Moral:
>         Use proper equipment and understand the theory before jumping to conclusions:
>
> Tenative conclusion:
>         FR-4 is acceptable for rise times of 500 psec and frequencies up to 1 GHz.
>
> ################################################################
> 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 web site (http://jefry.ipc.org/forum.htm) for additional information.
> For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
> ################################################################

################################################################
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 web site (http://jefry.ipc.org/forum.htm) for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################


ATOM RSS1 RSS2