Dual band antenna with I3ED

Hello guys!

i would like to build a dual band patch antenna with IE3D F1=10Ghz and F2=20GHz.
i would like to what is the best design to made it?

i think about a first patch with the resonant frequency F1 and a second patch over the first one feedind together with the same port but i don't know how to design a port who feed the two antennas.

thanks for your help.