How to make a tapered spiral antenna?

Hi all,
I want to make a tapered slot spiral antenna,would anybody help me about how I should draw and design it in cst software

You can generate the curve's (x,y) points in MATLAB/Octave/Excel/... using the equation for a spiral antenna.

Then import this curve into CST and then proceed from there.

Hi all,
would you please let me know the equation or the relationship for tapering the slot spiral antenna?

Please refer to it.

Is it antenna? Looks like coplanar. Witch frequency? 1.5GHz?:

i cannot download