CST mesh properties in Helix and spiral structures

Hi.
Everytime i simulate a Helix or a spiral structure, CST fill the antenna with PEC in staircase.
My mesh properties are set to default, how can i set the mesh properties to get good results?
I′ve tried to change the mesh properties, lines per wavelenght; lower mesh limit; mesh line radio limit...and never got good results.
This is a omni 2.4ghz antenna.

Nadabro!
In mesh view mode, right click on the object of the helix (at tree folder)
and choose (local) mesh properties - change there the local mesh of the helix antenna...

The only thing that can made those PEC Staircase disappear is using STAIRCASE MESH option in Local Mesh Properties..but the results are not good.
What kind of Mesh settings can i use without affecting the results?
thanks.

U can play around with meshing.
1) increase the frequency to higher value, it will improve the meshing:D although not good idea
2) Its better to change the tepmelate u start with, best one is
3) Go to File->select template->Antenna(free space,wavegide)
4) Meshproperties->special->equilibrate mesh