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Electric field distribution of microelectrodes

Posted May 23, 2012, 11:11 p.m. EDT Low-Frequency Electromagnetics, RF & Microwave Engineering, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 4.2a 1 Reply

Bashar Yafouz
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Hi everyone,

I am a new user to Comsol. I want to see the electric field distribution of a set of microelectrodes. The frequency of my AC excitation signal is in MHz.

1- I have chosen RF module to do this task. Is that the correct choice?

2- How can I input an "AC" signal? I mean, when I write "20*sin(10^6*t) " as the Vo in the terminal electric potential, it gives me an error coz "t" is undefined variable.

Thanks in advance for your help.
1 Reply Last Post May 24, 2012, 1:09 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago May 24, 2012, 1:09 a.m. EDT
Hi

check the doc, the decision between ACDC and RF comes from the relative size of your model compared to the EM wavelength size (which depends on the material index or epsilon_r. If the wavelength is very long compared to the model extent size it's rather ACDD, if the wavelength is much shorter than the model size its RF, when in the middle none or both it depends and you are in the grey zone ;( a good way is to compare both results and try to understand the simulitudes or differences then observed.

For the "AC" signal you have 2 approaches, time series with explicit V0*sin(2*pi*f*t) or harmonic development (frequency sweep) in omega=2*pi*freq mode, then you define amplitude and phase and the frequency or its sweep range. The latter is by far the cheapest, computationally

--
Good luck
Ivar
Hi check the doc, the decision between ACDC and RF comes from the relative size of your model compared to the EM wavelength size (which depends on the material index or epsilon_r. If the wavelength is very long compared to the model extent size it's rather ACDD, if the wavelength is much shorter than the model size its RF, when in the middle none or both it depends and you are in the grey zone ;( a good way is to compare both results and try to understand the simulitudes or differences then observed. For the "AC" signal you have 2 approaches, time series with explicit V0*sin(2*pi*f*t) or harmonic development (frequency sweep) in omega=2*pi*freq mode, then you define amplitude and phase and the frequency or its sweep range. The latter is by far the cheapest, computationally -- Good luck Ivar

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