tapered balun

Does anyone have any documentation of designing a tapered balun for a specific antenna. I want to design a sinuous antenna, cavity backed for frequencies 2-18GHz. But I don't know how to design the balun for the specific antenna.

Please help with sugestions, tutorials, documentations, examples...etc.

If one knows the input impedance of their antenna, how would one figure out the starting (unbalanced) and ending (balanced) width of the baluns?

go to this links:
https://www.edaboard.com/viewtopic.php?p=824907#824907

https://www.edaboard.com/viewtopic.php?p=824910#824910