CPW Calculation - RF Cafe Forums
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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.
Don't 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.