When you "an FSS" do you mean a completed and simulated design? If so, then just go to the Project Manager Box on the left side and click on YOUR_PROJECT >> YOUR_DESIGN >> FIELD OVERLAYS. Right Click FIELD OVERLAYS and click on the E fields. The E fields will be plotted on whatever object/surface/plane you have selected.
Thank you kthackst for your reply, but when i right click overlays then plot field then there options E or H or J or other, if i go with E there will be three options Mag_E or ComplexMag_E or Vector_E.
so which one to chose and how to see fields distribution at certain frequency?