Design Fresnel zone plate antenna in HFSS.

Any one help me to design Fresnel zone plate antenna in HFSS. The design has two elements. (1) A plate having circular rings of different radii. It can be made by printed technology on RT/duroid 5880. and (2) horn antenna as a feed. My doubt is how can I simulate this complete design (plate+horn)?
how to simulate this design.please please help me....