Because of the high maintenance needed to monitor and filter spammers from the RF Cafe Forums, I decided that it would
be best to just archive the pages to make all the good information posted in the past available for review. It is unfortunate
that the scumbags of the world ruin an otherwise useful venue for people wanting to exchanged useful ideas and views.
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Below are all of the forum threads, including all
the responses to the original posts.
Post subject: CPW Calculation Posted: Wed Sep 19, 2007 9:16 pm
Joined: Tue Sep 04, 2007 7:54 am
With the following parameters, I
am getting different answers with different tools.
H = 0.3mm
Er = 4.25
W = 0.56mm
gap = 0.35mm
Freq 1842 Mhz
With this Agilent Appcad gives 50.2 ohms. AWR Tx line gives 47 ohms.
Following online calculator gives 78 ohms.
understand the reason for this difference.
Post subject: Posted: Tue Sep 25,
2007 3:01 am
Joined: Tue Mar 15, 2005 11:43 pm
the difference is the ground plane.
I believe that for your first calculation (AppCad and
AWR) you included the groundplane (CPW ground)
While the online calculator is without ground plane.
you can double check the setting thru AppCad and also AWR (CPW and CPW ground).
Hope it helps.
Post subject: Posted: Tue Oct 16, 2007 5:40 am
Joined: Wed Jun 20, 2007 3:01 am
I'm with Jeanalmira
in his opinion. As for the lower impedance values you used -most probably- Grounded-Coplanar. While the larger
values is for the conventional coplanar waveguide -without lower ground plane-.
Kindly check this online
applet, it is for conventional coplanar waveguide.