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Electric field due to dipole in Comsol RF. Difference between closed form solution and comsol results

Posted 16 mag 2024, 07:38 GMT-4 Electromagnetics, RF & Microwave Engineering Version 6.1 2 Replies

Varatharajan Meenakshi Sundaram
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The field produced by the electric point dipole in COMSOL RF differs from that of the closed-form solution.

Simulation details:

  • Simulation domain is a square region of side length 2.2m with 0.1m allocated for PML along all six sides
  • Electric Dipole is located at the origin
  • Dipole moment is 0.001Am along the Z direction.
  • Frequency is 433 MHz

The closed-form expression is evaluated using the attached Matlab code, which implements the equations in the attached image in spherical coordinates and transforms the fields to cartesian coordinates. The absolute value of the field along the Z direction is plotted for the 2D slice at z=0.

Problem: The absolute values of electric fields are drastically different.

Question: Why is there a considerable deviation in the amplitude of electric fields? Is there anything wrong with the Comsol settings or the code implemented?

Can any one of you point out the issue?

2 Replies Last Post 21 mag 2024, 03:30 GMT-4
Robert Koslover Certified Consultant
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Posted: 6 months ago 17 mag 2024, 10:55 GMT-4

Just a couple quick guesses here: 1. This entry at the top of your .m file appears suspect: "epsilon0 = 8.85418782 " What happened to the 10^-12 factor?
2. The IdL dipole moment in your .m file is .01, but .001 in your .mph file, I think. Take another look at that too. 3. There are other features of your model I would probably investigate further and adjust, but let's start with those two items. I hope that helps.

-------------------
Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
Just a couple quick guesses here: 1. This entry at the top of your .m file appears suspect: "epsilon0 = 8.85418782 " What happened to the 10^-12 factor? 2. The IdL dipole moment in your .m file is .01, but .001 in your .mph file, I think. Take another look at that too. 3. There are other features of your model I would probably investigate further and adjust, but let's start with those two items. I hope that helps.
Varatharajan Meenakshi Sundaram
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Posted: 6 months ago 21 mag 2024, 03:30 GMT-4
Updated: 6 months ago 21 mag 2024, 03:33 GMT-4

Thanks a lot. I am out of my institution for a week. So I was not able to reply. I will investigate it further and post if there are further issues.

Thanks a lot. I am out of my institution for a week. So I was not able to reply. I will investigate it further and post if there are further issues.

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