Rogowski Coil High Frequency Limit
What limits the frequency of a Rogowski coil to below the GHz range?


Mainly the fact that it is by definition a multi-turn inductor, and the self-resonant frequency is going to be a few hundred MHz at best.

An inductor that has an impedance of 50&Omega; at 1.296 GHz has an inductance of 6.14 nH. That's a really tiny value, and it's really difficult to make a low-loss discrete inductor with that value. Another issue is that the skin depth for copper at that frequency is only about 2 microns. That's why most work at microwave frequencies is done with silver-plated tuned cavities and striplines.

What is it that you're really trying to accomplish? If you can be more specific, we can come up with more appropriate approaches for you to try.