On 26 ago, 19:38, qrk wrote:
On Tue, 26 Aug 2008 10:02:47 -0700 (PDT), Wimpie
wrote:



Hello,

Most formulas for microstrip transmission line assume that there is
dielectric all over the ground plane.

Does somebody know a formula (or graphical solution) for the
characteristic impedance of a microstrip where there is only
dielectric material under the strip (so you can see the ground
plane)?

Best regards,

Wim
PA3DJS
www.tetech.nl
The mail address is valid when you remove abc

http://atlc.sourceforge.net/
The above link is a wonderful arbitrary solver for transmission lines.
This is primarily a Unix program. If you need a Windows build of the
program, I probably have version 4.4 somewhere.

--
Mark

Hello Mark,

I received a windows build via Tom and created a .bmp file with the
structure (with MSPaint, save as .bmp, not .jpg). Result is OK (I
use Win2000 SP4). My hand calculation closely matches the simulated
result.

As long as ground (green color) surrounds your structure completely,
results are OK. If not (for example a real microstrip line), results
are unreliable.

I will make the line and check the VSWR with 50 Ohms termination.

Best regards,

Wim
PA3DJS
www.tetech.nl
when you remove abc, the address is valid.