Microstrip Dual Band Antenna Directivity Problem HFSS

Hello,

I am trying to design dual band microstrip patch antenna but I calculate very low directivity, gain values. I am trying to solve this for few days but I couldn't. Could you please help me?

Thanks...

Ansoft.rar

You need to increase the Ground plane size to increase the directivity. I changed the expression to -30*h + PatchX