panel size optimization by only thickness distribution

Hi. I want to solve the problem about erp reduction by free-size optimization(design valuable is only thickness)

 

It looks like easy problem but I want to know exact process.

 

If I have plate 180 [mm] x 180 [mm] and property = pshell (thickness = 2.5 [mm]), I want to reduce equivalent radiated power by size optimization by thickness distribution.

 

I want to set under bound = 1 [mm] and upper bound = 5 [mm].

 

It means that initial thickness(2.5 [mm]) can change 1 [mm].

 

Would you plz let me know how to set desvar, generic relationship in free-size panel in optimization panel.

 

Thanks a lot.