Electrical Length (Phase Shift in CST)

To everybody

Please refer to my attachment. What is the physical length (L) for my structure? How can I calculate the correct one?

For your information, I am using CST version 11.0? I need to determine the physical length before I can calculate the electrical length in theta (degree, not radian).

My question is:

How many phase shift that my structure have to go and so that I can obtain the beta value at 1 GHz?

Phase Shift=?
Frequency=1 GHz

Phase Shift=?
Frequency=10GHz

I am applying periodic to x-direction.

Single Turn.zipSingle Turn.zip