I would suggest Ansoft Designer, if available.

Another option (not available in the free version) consists in LayoutEditor: http://www.layouteditor.net/

You can export the HFSS design in a format readable by LayoutEditor, like .dxf, and then save it as a gerber file.

I have used LayoutEditor but for other purposes; I have never tried this procedure but in principle it should work. I hope this helps.

You can import your GDSII file to ADS momentum and there you can export gerber designs. Alternatively what i do is export the planar dxf file for each layer separately and create milling file from dxf directly,. If you are to make a layout film import dxf file to corel draw and make pdf or what ever you like,

I think you must go via ADS momentum, by importing GSDII file to ADS and then export it to gerber file.

use export command in hfss.

and then use any pcb designing software for dxf file

I agree with all previous answers, but here is a small tip. If your design shape includes curved or circular edges, it will appear in the layout as a small short linear segments in case you extracted directly from HFSS. To avoid this, you need to export "yourdesign.sat" from HFSS and import it in CST. Then, extract your gerber file directly from CST or extract "yourdesign.gds", then import it in ADS. If you did so, you will have perfectly rounded edges. On the other hand, if your design doesn't contain rounded edges, don't bother doing all of this :)

Moving the file into ADS Momentum is a very simple way to solve this issue. There you can export the gerber file with exact dimensions of your structure which you can directly feed into pcb layout machines.