Calculations of absorption/scattering spectra

How to use openEMS. Discussion on examples, tutorials etc

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Calculations of absorption/scattering spectra

Post by KarolCwieka » Mon 02 Jul 2018, 11:58

Hi everyone,

I want to calculate absorption/scattering spectra for spherical nanoparticles, but I’m new to FDTD and OpenEMS, so I need help.

In my system, plane wave propagates along x direction, and xz plane is a polarization plane. I know how to generate geometry, computational domain, and mesh but I’m totally not sure how to acquire exact data for absorption/scattering spectra. I found MSL port capable to collect values of incident/accepted power as output parameters. Intuitively, I located two MSL ports within computational domain near incident plane (xmin) and xmax. The problem is that the results (port.P_inc or port.P_acc) from port located near xmax, plotted versus frequency, are equal to zero or not available… Therefore, I’m pretty sure that I’ve done something wrong. I do not fully understand how to use MSL port. Maybe, MSL port functions differently or should be located in another manner.

I will be very grateful for any hint or suggestion how to set up the computations to calculate absorption/scattering spectra.


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Re: Calculations of absorption/scattering spectra

Post by thorsten » Mon 02 Jul 2018, 19:56


an MSL port is for microstrip lines (MSL), what you describe does not sound at all like a MSL? Thus I doubt you will get any kind of usable data from them.
Since what you try to do is a bit more complex I really think you have to make yourself much more familiar with numerical modeling and the FDTD method in particular.
But in general the radar cross section tutorial sounds more reasonable as a starting point?


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Re: Calculations of absorption/scattering spectra

Post by Hale_812 » Tue 10 Jul 2018, 02:26

isn't it a problem equivalent to RCS/scattering in setup?
Let me cite Thorsten: " (Plane Wave PW...) It's not a dummy box, it is the box in which the plane wave is excited. Inside it you have the excited + scattered wave (total field). Outside it only the scattered one."
So you just collect the scattered field. You can process it with NF2FF tool to see scattering in particular direction.

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