[moved] Designing microstrip balun for spiral antenna (2 to 18GHz) using HFSS

Dear all,

I am trying to design a cavity backed archimedean spiral antenna (2 to 18GHz) using hfss. Can anyone tell me how to model and simulate a balun for that using hfss?

Thank you.

General spiral antenna impedance is 110 ohms, so you can design a balun for 50 ohms to 110 ohm a tapered balun.