How to simulate the EMI after layout?

After layout the circuit ,I want to perform EM simulation to check the EMI.Which simulator can do this job?

ADS can do. But it is 2.5D simulation. HFSS can do 3D EM simulation. you can try!

Can HFSS perform Harmonic Balance simulation?I am now designing a mixer .

then, how will you transfer your design data between these tools?
GDSII?
or something else?

SI-wave may be do the job.