CST, HFSS, FEKO
but feko is the fastest
EMPro i know it uses fdtd method,
cst also uses fdtd
hfss uses FEM
FEKO uses MOM
if youdesign ultrawideband system fdtd methot is suitable
if you want analysis fast use feko (MoM)
if you want very very fast use analytic regularization method and use C/C++ or matlab
WIPL-D is an other 3D EM Solver.
It sould be pretty good, the guys programming it really seem to now their stuff, at least in theory (they wrote several books on this topic).
There is also a free trial version - however, I was unable to get anything useful out of it... so I actually would not recommend it.
when you use fdtd method you mesh the structure and your time domain pulse.the time domain pulse includes your frequency bandwith.But when use MoM (Frequency domain) you mesh only structure but you must calculate the frequencies one by one.If your structure has many details MoM method may be slower than FDTD.
I advice you when you desidn an antenna try in many simulation software because at that time you might not know the details of the solution method so you might design faulty.
You could try **broken link removed**. This is a wire MoM-code with conformal geometry modeling. It is the only MoM code with curved segments, which exactly follow the contour of helix, loop and spiral antennas. This feature improves the convergence rate compared to NEC-based softwares with straight wire segments.