Hello again,
I have simulated your inductor now. Before, I did not realize that it is single turn, so that the resistances are extremely small, on the order of 20mOhm. This means that any comparison to measurement suffers from accuracy problems in the measurement: contact resistance, resistance from soldering etc.
But let's start with the EM analysis first.
As I wrote above, for thin metal analysis, the simulator can not predict the skin effect current distribution on top/bottom of the trace. In Sonnet, we can set the skin effect current ratio manually, and I have plotted the extreme cases with current ratio = 0 (skin current on one side only) and current ratio = 1 (skin current on two sides). As you can see, they agree at DC (as calculated from metal thickness and conductivity) and diverge where skin effect takes over.
Your inductor does not have ground below, so we expect that current ratio = 1 with symmetric current on top and bottom should be more correct. For a thick metal analysis, where Sonnet calculates two sheets, the skin currents can be EM calculated, and we see that we are indeed very close to the current ratio = 1 (skin current on two sides) thin metal result.
In the plots, you can also see the extracted series resistance, which determines the Q factor. These resistances are very small for your model, and it will be difficult to measure this accurately. Your difference between measured and simulated is 20mOhm. From many years of consulting with on-chip inductor modelling and measured-vs.-simulated tests, I have a very strong trust in my Sonnet results, and know how difficult it can be to measure the Q accurately in the presence of contact resistance.
Best regards
Volker