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

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

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,

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

"Wimpie" wrote in message
...
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,

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.

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

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

On Tue, 26 Aug 2008 12:18:37 -0700, John Smith
wrote:

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 ...

Drifting further off topic.... Here's the commercial incantation of
that antenna (the three photos on the right) from Tecom:
http://802.11junk.com/jeffl/antennas/tecom/index.html
PCB losses make it a rather marginal performer.

Note the added decoupling sleeve. That somewhat beam uptilt due to
the effects of the mounting hardware.

The worst part of the design is that 1/2 the RF is radiated in the
first half wave (bottom two elements). 1/4th is radiated from the
next half wave. 1/8th from the next dipole, and so on. By the time
what's left gets to the top element, there's not much left. With all
the RF coming from the base of the antenna, and with the uptilt
problem, it's often best to mount the antenna in an inverted position.

I have an NEC2 model somewhere but it has problems. Sorry.

However, I do agree with the article's conclusions. It is a cheap
antenna to build.

As for the original question, ATLC is certainly the right answer for
modeling a rather unusual microstrip configuration. The program can
allegedly be built using Cygwin for Windoze. I haven't tried it:
http://atlc.sourceforge.net/installing.html
Note the spelling of Windoze on that page. I looked through the
ported package list, but didn't find ATLC.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Tue, 26 Aug 2008 11:02:15 -0700 (PDT), Wimpie
wrote:

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,

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.

--
Mark

qrk wrote:
On Tue, 26 Aug 2008 11:02:15 -0700 (PDT), Wimpie
wrote:

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,

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.


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

--
Regards, Joerg

http://www.analogconsultants.com/

"gmail" domain blocked because of excessive spam.
Use another domain or send PM.

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.

On Aug 27, 11:25*am, qrk wrote:
On Tue, 26 Aug 2008 11:02:15 -0700 (PDT), Wimpie
wrote:



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,

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.

--
Mark

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