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Calculating Complex Permittivity
Posted 2025年3月12日 GMT+8 19:30Electromagnetics, Materials, Equation-Based ModelingVersion 6.22 Replies
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Hi, I'm trying to calculate the complex permittivity of graphene using this formula
hereσis the conductivity,ω=2πfis the angular frequency,ε0is the dielectric constant of the vacuum, and t is the thickness of the material. In COMSOL, this formula should look like this
1-(j x sigma)/(epsilon0_const x comp1.ewfd.omega x d_eff)
(I changed asterisks to x, because on this forum asterisks turn textItalic)
But for some reason, COMSOL assigned an "rad" unit to this formula even though all variables are right
What's wrong and how do I fix this?
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From this [https://www.researchgate.net/publication/283380681_Optical_properties_of_graphene_on_quartz_and_polyethylene_substrates_in_terahertz_frequency_range] it looks like you are expecting unit less for that permittivity? I think what you get is correct seen from how omega here is rad/s, but you could also write omega as 2pifrequency, with frequency having unit Hz, in which case you have no resulting unit.
-------------------René Christensen, PhD
Acculution ApS
www.acculution.com
info@acculution.com
Please login with a confirmed email address before reporting spam
From this [https://www.researchgate.net/publication/283380681_Optical_properties_of_graphene_on_quartz_and_polyethylene_substrates_in_terahertz_frequency_range] it looks like you are expecting unit less for that permittivity? I think what you get is correct seen from how omega here is rad/s, but you could also write omega as 2pifrequency, with frequency having unit Hz, in which case you have no resulting unit.
It works thanks. I realized what the problem was. comp1.ewfd.omega is 2 x pi xewfd.freqnot thecomp1.ewfd.freq
