[HFSS] How may I calculate the magnetic field being coupled through a defined surface

[sandbo]

Sorry if this is a duplicated question, but I am working on this and hope to extract the data within this week, after some tries I decided it maybe better to seek advice.

It's actually the same simulation I was running in a previous question:
https://www.edaboard.com/threads/327356/

The magnetic field is being coupled from the Red CPW line to the square within the Blue CPW line, with the below setup:

Using the plot field feature to give the mag and vector plot of the field through a define non-model square overlapping the hollow in the blue CPW line, I am able to visualize the field and strength, which both looked pretty good.
To extract the number, I tried to use the field calculator:
In Tabs, HFSS-->Field-->Calculator

But then in that I found a lot of expressions, I tried a few of them intuitively like:

However I cannot really tell if that's correct, much appreciated if you don't mind correcting me or sharing with me how this maybe done.

 

[PlanarMetamaterials]

Hi sandbo,

It looks to me that your definition is correct. I think you're just looking for the magnetic flux through the surface, so it's a fairly straightforward calculation.

 

[sandbo]

Hi sandbo,

It looks to me that your definition is correct. I think you're just looking for the magnetic flux through the surface, so it's a fairly straightforward calculation.

Thanks a lot, in fact I am getting numbers pretty close to the expected, however the thing bothered me is when I tried to plot the flux normal to the square, I get fluctuating values, instead of the exponential decay of field I expected.

However from the vector plot, I do see the arrow decreasing with distance of the hollow area from the center Red CPW line.

 

[sandbo]

I am pretty frustrated, though I am not quite confident with the expression, in which I call the surface, take a dot product of the vec_H with the normal to that surface, and then integrate the dot product over that surface, I am getting a fluctuation like below, while I expected an exponential decay, much appreciated if any ideas can be provided.