Microstrip formula for non-standard geometry

[Wimpie]

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

 

[qrk]

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.

 

[Wimpie]

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.

Hello Mark,

This is good one (I found it via google also). You can enter both
metallics and dielectrics as you want. It would be very nice when you
can mail me a Windows Build (I hope it is not that big). A link would
also be useful.

My address is valid when you remove abc.

Best regards and thanks,

Wim
PA3DJS
www.tetech.nl

 

[JB]

Hello Mark,

This is good one (I found it via google also). You can enter both
metallics and dielectrics as you want. It would be very nice when you
can mail me a Windows Build (I hope it is not that big). A link would
also be useful.

My address is valid when you remove abc.

Best regards and thanks,

Wim
PA3DJS
www.tetech.nl

AFAIK dielectric between the strip and GP is the most significant unless
stripline is to couple to other stuff. Anytime you change board material
there are subtle changes in VF. For proto, I always like to allow for
trimming where it has to be critical, but best to make it less critical so
you don't have to spend time on every board. Air is better, but spacing
variations come into play, and what will happen if you drop it. The
calculations only get you so far unless you have your constants handy.

 

[John Smith]

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

This is a bit off topic in direct relation to your post; however, I
built this antenna as an external to my wifi router/switch to increase
coverage of the net:

http://www.centurion.com/home/pdf/wp_omni_wireless.pdf

Fig. 1-5 and the plot of the radiation pattern (fig. 1-7) I found
particularly interesting ...

Regards,
JS

 

[qrk]

Hello Mark,

This is good one (I found it via google also). You can enter both
metallics and dielectrics as you want. It would be very nice when you
can mail me a Windows Build (I hope it is not that big). A link would
also be useful.

My address is valid when you remove abc.

Best regards and thanks,

Wim
PA3DJS
www.tetech.nl

I will keep this on the web site for a few days. About 3MB download.
http://qrkwiggles.googlepages.com/atlc-4.4.4_Win32.zip

This version has problems with muliple dielectrics. I works fine with
two dielectrics, air and one of your choosing.

 

[Joerg]

I will keep this on the web site for a few days. About 3MB download.
http://qrkwiggles.googlepages.com/atlc-4.4.4_Win32.zip

This version has problems with muliple dielectrics. I works fine with
two dielectrics, air and one of your choosing.

Thanks for sharing this, Mark. I'll try it out as well, just not right now.

 

[Wimpie]

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.

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.

 

[K7ITM]

I will keep this on the web site for a few days. About 3MB download.http://qrkwiggles.googlepages.com/atlc-4.4.4_Win32.zip

This version has problems with muliple dielectrics. I works fine with
two dielectrics, air and one of your choosing.

The version I have, which I sent to Wim, is 4.6.0. I'm not sure about
the differences, but if anyone is interested, I have it in a zip file
I can send. The zip file is encrypted, so it will pass through at
least some of the email filters that take out executables or zips with
embedded executables; I'll supply the password of course (just my
call...).

Cheers,
Tom

 

[qrk]

The version I have, which I sent to Wim, is 4.6.0. I'm not sure about
the differences, but if anyone is interested, I have it in a zip file
I can send. The zip file is encrypted, so it will pass through at
least some of the email filters that take out executables or zips with
embedded executables; I'll supply the password of course (just my
call...).

Cheers,
Tom

4.6.0 is the latest version which fixes the multiple dielectric
problem. I believe this version is had multiple processor support
removed since the author had problems getting it running properly.

Where did you get the Windows build from? My work colleague was the
last one to supply Dr. Kirkby a windows build which was ver 4.4.4. It
would be great if you could give Dr. Kirkby the latest windows build
so he can post it.

 

[K7ITM]

4.6.0 is the latest version which fixes the multiple dielectric
problem. I believe this version is had multiple processor support
removed since the author had problems getting it running properly.

Where did you get the Windows build from? My work colleague was the
last one to supply Dr. Kirkby a windows build which was ver 4.4.4. It
would be great if you could give Dr. Kirkby the latest windows build
so he can post it.

Ah, OK; I thought from the atlc website that we'd just all be on our
own to do it. I'm an analog guy; I enlisted the help of a digital/
software friend. He had no trouble building it to run in a DOS
shell. I'll drop David a note, letting him know that I have it, to
see if he'd like it there.

Cheers,
Tom

 

[JeffM]

http://atlc.sourceforge.net/
[...]arbitrary solver for transmission lines.
This is primarily a Unix program. If you need a Windows build[...]

I will keep this on the web site for a few days. About 3MB download.
http://qrkwiggles.googlepages.com/atlc-4.4.4_Win32.zip
This version has problems with muliple dielectrics.

The version I have, which I sent to Wim, is 4.6.0
Tom

Note to Tom:
If you are going to continue to post via Google, you should read this:
http://groups.google.com/group/sci....gle.blockquotes.them+long-links+get.butchered

4.6.0 is the latest version
which fixes the multiple dielectric problem.
Where did you get the Windows build[ ]?

Pursuing this via Google,
http://www.google.com/search?q=+atlc++Win32+-4.4.4+mdtlc
(Why they won't give you, by default, WHAT YOU ASK FOR
http://www.google.com/search?q=atlc+Win32+-4.4.4
really pisses me off.)

Anyway, I discovered !!!
http://www.google.com/search?q=cach...tiple.Dielectric.Transmission.Line.Calculator

 

[TheM]

Anyway, I discovered !!!
http://www.google.com/search?q=cach...tiple.Dielectric.Transmission.Line.Calculator

I'm just downloading mdtl from sourceforge, will give it a try as soon as I find some free time.
Cool link, thanks for some detective work

M