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Electric field evaluation and unit

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1. Can someone explain why the electric field, magnetic field units on comsol is V*m, A*m instead of V/m, A/m?
Or is there any other method to evaluate electric field, magnetic field or poynting vector than from integration under derived values in result menu?

2. I am working in RF module to evaluate the skin depth of the electromagnetic field in a medium (e.g from air to concrete or liquid). Is it possible to evaluate the skin depth of electromagnetic field in a medium from RF module?
I have tried to evaluate the poynting vector probably i can use it to latter derive an expression to evaluate the skin depth but its seems not working.
Thank you in advance as awaiting your replies.

1 Reply Last Post 28 set 2016, 16:16 GMT-4
Robert Koslover Certified Consultant

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Posted: 8 years ago 28 set 2016, 16:16 GMT-4
1. Under what circumstances do you observe those peculiar units of E and H? In my Comsol Multiphysics models, I am accustomed to seeing the units of E and H as V/m and A/m, respectively. Also, no, you generally do not have to integrate anything under the "derived values" section just to compute or plot components of E or H. In most applications, if you are likely to need to compute or plot E or H, then those quantities are already available as post-solution variables, for you to select from. For example, in the RF module, the components of E are available to you as emw.Ex, emw.Ey, and emw.Ez.

2. You might want to post your model to this forum, so that others can see what might be causing your problem. Note that you should indeed be able to model the tapering of the fields as they penetrate partially into a partially-conducting medium, if you set the problem up correctly. Bear in mind that along with the fields tapering as they penetrate the media, there can (and generally will) also be some reflection of waves at the interface. The latter can confuse some people if/when they attempt to compare and understand the field amplitudes on the two sides of the interface in question.

Good luck.

1. Under what circumstances do you observe those peculiar units of E and H? In my Comsol Multiphysics models, I am accustomed to seeing the units of E and H as V/m and A/m, respectively. Also, no, you generally do not have to integrate anything under the "derived values" section just to compute or plot components of E or H. In most applications, if you are likely to need to compute or plot E or H, then those quantities are already available as post-solution variables, for you to select from. For example, in the RF module, the components of E are available to you as emw.Ex, emw.Ey, and emw.Ez. 2. You might want to post your model to this forum, so that others can see what might be causing your problem. Note that you should indeed be able to model the tapering of the fields as they penetrate partially into a partially-conducting medium, if you set the problem up correctly. Bear in mind that along with the fields tapering as they penetrate the media, there can (and generally will) also be some reflection of waves at the interface. The latter can confuse some people if/when they attempt to compare and understand the field amplitudes on the two sides of the interface in question. Good luck.

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