How to assign the port in HFSS for spiral antenna?

Hello Everybody:

I'm having a really hard time trying to design a spiral antenna. Design parameters are not really fixed, I fact I may choose among log,arquimedian,equiangular or even square spirals but I having trouble fiding papers with fixed information about how to do it, specially about the broadband balun for feeding and sizes of each element.

I'm trying with HFSS but I having problems assigning the port. I want to use a port without a balun, I mean, simulate the spiral with an ideal excitation without a balun or coax just for trying the body of the spiral. Is these possible and is It possible using HFSS 9.1?

I have look trhough all the forum, but I don't find something that could help me. If some of you find some other topic that may help, that information will be very wellcome :)

Please could somebody help me, thanks in adnvace!

P.D. Please excuse my English. I'm a Spanish student and I don't feel very confident about my grammar ;)

Pls explain your design title more specific.
There are a lot of ways to design different spirals. which parameters are more important for you?

your best resort is to upgrade to HFSS12.1 and use the Antenna Design Toolkit which has several Spiral antennas that it will autogenerate for you.

have fun! :)