Far field source in CST...

Hello everybody,
I am trying to make a far-field source in CST MWS, with the incident E field as follows:
E_inc= {Sin(phi_i) , - Cos(phi_i)} exp[j k (x Cos(phi_i) + y Sin(phi_i))]
Then calculate the absolute current density on a patch antenna surface.
How can I input such an incident in CST MWS or even HFSS?
Thanks in advance!

hi
i dont know how u can cst but in hfss i seen incident wave in executive boundary