archimedean spiral antenna with cst

hi all,
can anyone help me with designing archimedean antenna with cst.
esp. the excitation.. how to use the lumped element port.. which material that i should choose.. etc
and if u dont mind, please upload one of your design for example..
thank you for your help

regard.

I think this antenna design is available with the design macro of CST. have a look .. also you can just define the port between antenna element and ground plane.

Regards