design of circular microstrip antenna

hi guys,
i have a problem about the designing antenna.
if you know how i can design antenna with HFSS10 please tell me.
this is my homework's title ''Single-Layer Single-Feed Dual-Frequency Circular
Microstrip Antenna With an Offset Open-Ring Slot''
if you know something about it please tell me.
this the image of the antenna which is i must do.