How to estimate Disk Structure Inductance? Help!

I am developing a method to estimate semirigid coaxial cable parameters. This method needs a copper disc in order to short circuit the outter conductor and the center conductor. This disc has a hole in its center for the cable inner conductor to penetrate it (the disc is like a copper washer). Once conected to the cable, the current in the disc structure flows in radial maner.

What I need to know is the inductance of the copper disc, measured between the center and the outside (the disc it is going to operate at 1275MHz).

In fact, I need an estimation of inductance value (equation for example) or a way to simulate the structure (in HFSS 8 or Ensemble 7 preferentialy).

Thanks!