Electric field plot

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Hi, I am using the scattering field formulation for my model. I am using an x-polarized negative z-propagated plane wave as my background electric field. My structure is a box consisting of an air domain(top) and cancer domain(below). I used scattering boundary conditions. After the simulation, I realized that 1. emw.normE = abs(emw.Ex) 2. but abs(emw.Ez) is not = 0. if 1 is true, then how is 2 possible(since i am propagating the z direction anyways). or i am not plotting it correctly. I have attached my file. Thanks



1 Reply Last Post 16.08.2024, 20:02 GMT-4
Robert Koslover Certified Consultant

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Posted: 4 hours ago 16.08.2024, 20:02 GMT-4
Updated: 4 hours ago 16.08.2024, 20:07 GMT-4

Your example, at least as provided, is geometrically simple, but computationally very large, due to the small wavelengths involved relative to the model geometry. Your "cancer" material is defined as having a relatively high dielectric constant and also a relatively high conductivity. As such, it is very reflective to a direct incident RF wave at the specified frequency. I prepared a modified model simply to get it to execute. I made that model less wide in the two lateral dimensions and used linear elements and a user-specified mesh to keep the model computationally small enough. I noticed you did not take advantage of Comsol's built in tool for specifying plane wave RF incidence, so I changed your model to use that, and I encourage you to take a look at that. Frankly, this is still not a very good model for the purpose of investigating such a high frequency (500 GHz) wave interacting with your target. Computed penetration of such a 500 GHz wave is surely quite minimal into this material, at least if it really has the properties (dielectric constant and conductivity) that you specified, at that extreme frequency. The model also shows this more or less, but I still wouldn't trust the computed details for the penetrated field quantitatively here, since there are likely numerical noise issues. Perhaps you could redo this model with a much thinner layer for the "cancer" (since barely any field is getting into it anyway) and then could mesh that "cancer" domain more finely, if you really want to study it in detail. You could also try a 2D model, since that would help enormously in reducing your computational size. I hope that helps. Good luck.

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Scientific Applications & Research Associates (SARA) Inc.
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Your example, at least as provided, is geometrically simple, but computationally very large, due to the small wavelengths involved relative to the model geometry. Your "cancer" material is defined as having a relatively high dielectric constant and also a relatively high conductivity. As such, it is *very* reflective to a direct incident RF wave at the specified frequency. I prepared a modified model simply to get it to execute. I made that model less wide in the two lateral dimensions and used linear elements and a user-specified mesh to keep the model computationally small *enough*. I noticed you did not take advantage of Comsol's built in tool for specifying plane wave RF incidence, so I changed your model to use that, and I encourage you to take a look at that. Frankly, this is *still* not a very good model for the purpose of investigating such a high frequency (500 GHz) wave interacting with your target. Computed penetration of such a 500 GHz wave is surely quite minimal into this material, at least if it *really* has the properties (dielectric constant and conductivity) that you specified, at that extreme frequency. The model also shows this more or less, but I still wouldn't trust the computed details for the penetrated field quantitatively here, since there are likely numerical noise issues. Perhaps you could redo this model with a *much thinner* layer for the "cancer" (since barely any field is getting into it anyway) and then could mesh that "cancer" domain more finely, if you really want to study it in detail. You could also try a 2D model, since that would help enormously in reducing your computational size. I hope that helps. Good luck.

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