As you know software use solvers either from the integral equations family (like MoM) or from the differential equations family (FDTD, FIT, FEM) and it depends on the kind of your antenna. if you use planar antenna I advise you FEKO or HFSS. if you are interested to the current distribution on surfaces and borders , i advise you CST.

i prefer HFSS then CST and then microwave studio

i worked on HFSS, CST and I like HFSS 

Try here for more information about CAD Tools used for microwave simulations

http://uwaverf.altervista.org/forum/viewforum.php?f=19

thanks a lot to everyone for your valuable suggestions.

i worked on HFSS, CST and IE3D

u try HFSS and CST 3D EM