Mesh Cell Dimensions

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Hi all,

I am trying to calculate the conductivity at each point along the length of a semiconductor using the equation:

But my question is how can I find the individual L (x dimension) of a cell from my mesh to do this calculation. All I can find is the parameter 'h' which is the length of the longest edge of the element, and that is not along the correct direction (in my particular model the longest edge is along the y direction). Any suggestions will be welcome!


2 Replies Last Post 2020年7月8日 GMT-4 下午2:18
Robert Koslover Antennas, Waveguides, Electromagnetics

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Posted: 4 weeks ago 2020年7月7日 GMT-4 下午9:55

Hmm. Not sure what module you are using there, but your equation sure looks a lot like the customary J = sigma * E to me, where E = electric field, if I set E = V/L. Now, if you are using one of the standard Comsol modules, then I suspect that the vector components of J and E are being computed when you solve the problem and are available to you in post-processing from pull-down menus. If so, and assuming you have decided that you want to use those to extract sigma (rather than use some other definition of sigma), then you can always construct J/E in the direction of your choice. For example, in the RF module, emw.Jx/emw.Ex should work. (Of course, I'm assuming that your sigma, if a matrix, is a diagonal one.) Does that help?

Hmm. Not sure what module you are using there, but your equation sure looks a lot like the customary J = sigma * E to me, where E = electric field, if I set E = V/L. Now, if you are using one of the standard Comsol modules, then I suspect that the vector components of J and E are being computed when you solve the problem and are available to you in post-processing from pull-down menus. If so, and assuming you have decided that you want to use those to extract sigma (rather than use some other definition of sigma), then you can always construct J/E in the direction of your choice. For example, in the RF module, emw.Jx/emw.Ex should work. (Of course, I'm assuming that your sigma, if a matrix, is a diagonal one.) Does that help?

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Posted: 4 weeks ago 2020年7月8日 GMT-4 下午2:18

Oh yes! I tunnel visioned too hard on the variables, the electric field is 100% what I should have been looking for, thank you so much!

Oh yes! I tunnel visioned too hard on the variables, the electric field is 100% what I should have been looking for, thank you so much!

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