I am used to generate mictrostrip to layout and then export to gerber in ADS.
However, I am first time dealing with CPWG lines. I can see CPWG converted in the layout with center conductor (line width W) and thin ground lines at distance (Gap=G) apart.
I can see the same once I export the layout to gerber.
However my doubt is why the outer ground lines are so thin and not the typical PCB layout lines where we have center conductor and a gap, and a ground everywhere else (the way it should look like as shown in the attached image "Expected").?
Not sure which ADS element you have used. The thin line might be there to indicate the gap width, and the electrical model assumes a wide, large ground. My interpretation is that you must add the ground manually, outside that gap indicated by the thin line.