Thank you Constantin,
I think you are right that it might be done by properly defining Custom
Design Rules.
However, I am struggling implementing this and I wonder if you can help me.
My starting point is shown in the PieceWise1.jpg image. The desired gap on
the Grounded CoplanarWaveguide is 8.01 mil and the Anti-pad release is
8.68504 mil, both exactly as it should be when specified by Wire-Wire and
Wire-Pad clearances.
The problem is however that the Anti-pad is represented by piecewise linear
approximation instead of a smooth circle.
So as the first step I am increasing Wire-Pad clearance to 12 mil as to
allow nice covering of the piecewise linear approximation by an additional
wide arc with to get desired Anti-Pad radius.
For this I am changing the Wire-Pad design rule as shown in PieceWise2.jpg
image.
Now, I am drawing a wide arc (defined as DGND signal, same as the poured
DGND polygon). The parameters of the arc are shown in the PieceWise3.jpg
image.
(I am using the following command:
ARC 'DGND' CW FLAT (1997.1477 1798.3743) (1995.6286 1745.0258) (1969.7139
1770.9405) 14;
The problem is that the width of the arc as I calculated it in order to get
the desired Anti-pad release should be 14 mil, but in reality I can't get
it wider than 8 mil, probably because of the Wire-Pad rule. So, I have
tried to define a custom design rule for Wire-Pad, but I can't get it
working, it doesn't seem to make the arc wider than 8 mil. My definitions
for the custom design rule are shown in the same PieceWise3.jpg image. I am
certain that I have not defined the rule properly and would like to ask you
to take a look at it and hopefully make it work.
I think I will also have to add small lines (again by using the arc
command) to fill small gaps that will remain after applying the wide
semicircular arc, but I think once I will understand how to make custom
design rules I will be able to do it.
Thanks for your cooperation and help,
Ilia