How to draw and excite an impedance helix in HFSS?

Hi friends!
I′m new in HFSS and
I′m make a helix antenna for 2.45Ghz in HFSS and i′ve to make the feed, the excitation, but i saw the HFSS user guide and i draw the coax, if i change the lenght of the coax change the input impedance, how can i draw the coax with the correct lenght for this frequence? or how excitate my antenna with the corrects parameters for this frequency?

i′m posting the draw of my antenna


Thank you!

Hi Erick_Lopes,

I realize that it has been a while after you have submitted your question. I just want to make sure you have seen the "Helical Antenna" example created by Ansoft. As you may have seen you can can add a feed pin at the bottom of the helix and then feed it with a wave port backed by a copper box(you do that to be able to add the wave port internally).

I hope this helps.
Joline

can you elaborate this?