Large wavelength to feature size mismatch: Limitation of COMSOL simulations?

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Is it possible to simulate the interaction of a ~ 3000 micron beam with an object with 1 micron smallest feature size (currently using Wave Optics module)?

I read that there are limitations of conventional EM simulations when the mistmatch between the wavelength and feature size becomes very large. How can I determine when/if this is the case?


3 Replies Last Post 31/05/2020, 18:39 GMT-4
Edgar J. Kaiser Certified Consultant

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Posted: 5 months ago 31/05/2020, 03:55 GMT-4

Andrea,

best is to make a model that can be compared to an analytical solution.

Cheers Edgar

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Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
Andrea, best is to make a model that can be compared to an analytical solution. Cheers Edgar

Dave Greve Certified Consultant

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Posted: 5 months ago 31/05/2020, 18:33 GMT-4

I read that there are limitations of conventional EM simulations when the mistmatch between the wavelength and feature size becomes very large.

If a student said that I would ask where he read that and why the author says it happens.

If you wanted to do a comparison between simulation and analytic solutions, then scattering of a plane wave by a sphere would be a good test problem. The Rayleigh scattering solution is valid in the limit of a very small sphere in relation to wavelength, and the Mie scattering solution is valid for larger spheres.

> I read that there are limitations of conventional EM simulations when the mistmatch between the wavelength and feature size becomes very large. If a student said that I would ask where he read that and why the author says it happens. If you wanted to do a comparison between simulation and analytic solutions, then scattering of a plane wave by a sphere would be a good test problem. The Rayleigh scattering solution is valid in the limit of a very small sphere in relation to wavelength, and the Mie scattering solution is valid for larger spheres.

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Posted: 5 months ago 31/05/2020, 18:39 GMT-4

Thanks for the feedback--I think I have quite a bit more reading to do to understand this issue. I'll check out modeling the simple case of scattering from a sphere, as you mentioned, and compare this the Rayleigh scattering solution to get a better idea of the limitations of the simulation.

Thanks for the feedback--I think I have quite a bit more reading to do to understand this issue. I'll check out modeling the simple case of scattering from a sphere, as you mentioned, and compare this the Rayleigh scattering solution to get a better idea of the limitations of the simulation.

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