Exposure to an RF Electromagnetic Pulse
Posted 19.03.2026, 05:37 GMT-4 Electromagnetics, RF & Microwave Engineering, Modeling Tools & Definitions Version 6.4 1 Reply
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Hello there!
I am a newcomer to COMSOL Multiphysics and I am currently attempting to set up a simulation involving the exposure of a object to a radiofrequency (RF) electromagnetic pulse. The primary objective is to study the thermal and electromagnetic physical parameters (temperature, EF distribution). I am aware that the appropriate tool for this type of problem is the RF Module; however, I remain uncertain as to which of its physics interfaces best suits my case. Having briefly reviewed the available options, I have identified interfaces such as Electromagnetic Waves, Frequency Domain (emw) and Electromagnetic Waves, Time Explicit, among others, but I lack the background to determine which most accurately captures the physics of RF pulse propagation. I am also encountering difficulties in correctly defining the boundary conditions. Specifically, I am unsure how to set up the RF pulse excitation source and how to handle the outer boundaries of the computational domain. I have come across conditions such as Scattering Boundary Conditions and Perfectly Matched Layers (PML), which appear to be relevant for suppressing spurious reflections at the domain boundaries, but I have not yet been able to understand how to apply them correctly within the context of my model.
In light of the above, I would be most grateful if members of this community could direct me towards:
Official COMSOL tutorials or Application Library models addressing RF exposure. Should any member of the community have already addressed a similar problem and be willing to share a worked example or provide direct guidance, I would be most grateful for their contribution;
Guidance on which physics interface within the RF Module is most suitable for this class of problems;
Introductory documentation or methodological references appropriate for users approaching coupled electromagnetic–thermal modelling for the first time.
Any guidance, even of a general or preliminary nature, would be of considerable value at this stage. Thank you in advance for your time and expertise.
Kind regards
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It depends on the regimes you are trying to model. If you are working with a very short pulse (e.g., just a few cycles) then a time-domain RF model is more appropriate than a frequency domain model. If your pulse is hundreds of cycles long (or even longer) a frequency-domain RF model may be a better choice. If your object is relatively small and your illumination is plane-wave like, you may wish to expose it within a transmission-line (TL) like geometry, using a field (or port) defined at the input end, a scattering boundary (or port) at the output end, and PEC and PMC walls on the sides, according to the polarizations that go there (which you will need to specify). You will have to choose/specify the time step(s) wisely; Comol's default values for the time step will likely be useless. You will have to add a thermal time-dependent model as well and couple the multi-physics. Overall, this is not a model for beginners. Model various pieces of the physics separately first, to make sure you understand what you are doing. Also, model everything in 2D before you attempt 3D. You will need to build and study and execute many models, building toward your goal before you'll get there. Don't attempt to shortcut to a full 3D RF pulsed time-domain model including heating of the test object, all in one (your first) model. First you learn to stand, then to walk, and then to run.
-------------------Scientific Applications & Research Associates (SARA) Inc.
www.comsol.com/partners-consultants/certified-consultants/sara
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