problems of a differential-driven MSA (Hfss)

hello everyone here,I have just learned to use HFSS these days...
Now I am trying to do the same simulation likehttp://0rz.tw/cd48Y

As usual , I draw the probe and the pin.(I guess this paper uses probe = =)
but i am not sure the way to "excite" those differntial signal.....
I draw two rings ,and orient the current from inner side of the ring
to the outer side of the ring.

I wonder if my model is right or not...