Unit of conductivity - Githubissues

flaport / fdtd

A 3D electromagnetic FDTD simulator written in Python with optional GPU support

https://fdtd.readthedocs.io

MIT License

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Unit of conductivity #28

Closed chenyang9526 closed 2 years ago

chenyang9526 commented 2 years ago

Hi @flaport, thanks for the excellent toolbox. Just a quick question, may I know the unit of conductivity defined in the absorbing object? In your example (https://fdtd.readthedocs.io/en/latest/examples/02-absorbing-object.html#), the conductivity was set to 1e-6, but the unit was not provided. I'm interested in a medium that has a conductivity of 0.6 ohm-1 m-1. However, if I set the conductivity to 0.6, the program gives a absorption_factor larger than 1. Could you give me any suggestions on setting the correct conductivity for your toolbox. Thanks!

flaport commented 2 years ago

Hi @chenyang9526 , the simulation unit for the conductivity in the AbsorbingObject is s-1. To obtain the simulation units from the physical units, divide by εε0:

σ_sim = σ_phys / (ε ε0)