CAD File for Self-Complimentary Archimedean Spiral Antenna

Hello All,
I'm attempting to make a CAD file (to be used on a milling machine for a microstrip antenna) of a self-complementary 2-arm Archimedean spiral antenna. The inner radius (i.e. upper frequency limit) should be around 1.91cm, and the outermost radius (i.e. lower frequency limit) should be around 5.97cm. I'm not really sure how to design this in CAD. AutoCAD is the most accessible software for me, though I can get access to Inventor as well. I've read through most of the spiral antenna threads on these boards, and some of them even have code, however, I'm not sure how to go about modifying that code. I was hoping someone might know how to create a 2D spiral like this in a CAD program.

Thank you in advance,

- Chris