Exchange format for Keysight Momentum on ADS

If I want to port layout data to Keysight Momentum on ADS from other layout tool such as KiCad, what data format should I use ?

Gerber Format is not useful.

Is DXF candidate ?

DXF or if you have ODB++ file that can be also used.

My ADS is 2009U1.
I don't think ODB++ is supported in ADS2009U1.

I don't have license for importing DXF.
I have licenses for importing Gerber and GDSII.

My wish is to convert Gerber with unifying to GDSII.

Is there any freeware to do such task ?
https://www.klayout.de/

Having worked on these RF layout data translators for many years, I'm not aware of any free solutions.

Actually, the merging part isn't trivial. Many EDA tool manufacturers use the Gerber Union translator engine by Artwork Conversion.
http://www.artwork.com/gerber/gerber_union/index1.htm

Edit: I see that you already have a Gerber import license for your ADS2009? Any issues with using that?

Yes.

Union function is not available in ADS2009U1.
I think Union was available in ADS2005.

Union is available in preview editor in ADS2009U1, however I have to save data as DXF.

I think Gerber union require another license in current ADS.
http://www.keysight.com/ja/pd-211105...t?cc=JP&lc=jpn