How to draw the coaxial cable feeding for spiral antenna design in CST?

Hi...
can u all tell me how to draw the coaxial cable feeding for spiral antenna design?what the material is used.and is it need to calculate?

You can draw a coaxial cable by drawing a pec cylinder and inserting a dielectric cylinder in it with inner and outer radii corresponding to the radius of the inner conductor and the radius of the outer conductor.
The most commonly used dielectric in coaxial cable is Teflon. It has a dielectric constant of about 2.1 and a very small loss tangent.
BR,
Adel