Homebrew PCBs

----- Original Message ----- 
From: "Gavin Dingley" <dingley76@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, June 11, 2008 6:05 PM
Subject: Re: [Homebrew_PCBs] How to mask bottom layer from etching?


> Hi Lanny,
> I was just wondered what frequency you will be operating the microwave 
> circuit, and what board you are using. As I understand it you can use FR4 
> up to 2GHz, beyond this you need special board which is made of a low-loss 
> dielectric material. Also if you are using standard FR4, is there not a 
> problem due to tolerances/variations associated with the board thickness 
> over an area, as this will change the characteristic impedance of 
> micro-strip lines - along the line (if you can see what I mean).

Radio amateurs often use FR4 above 2 GHz without any problems. Special 
dielectrics are only needed for high-performance applications.

Leon
--
Leon Heller
Amateur radio call-sign G1HSM
Yaesu FT-817ND and FT-857D transceivers
Suzuki SV1000S motorcycle
leon355@...
http://www.geocities.com/leon_heller