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Conductivity of the antenna, RF module
Posted Oct 18, 2012, 10:44 a.m. EDT RF & Microwave Engineering Version 4.2a 2 Replies
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Dear All,
I have question concerning optical antennas.
I have model which consist of the optical antenna on substrate, and I want to calculate scattering cross section and field enhancement.
My question is about sigma (conductivity). Does any of you know what is the difference between case when we put that antenna is perfect electric conductor (sigma = 0), and case when sigma is depend on wavelength of illumination of that structure?
So actually I need some theoretical instructions if any of you is familiar with that.
Regards and thank you
I have question concerning optical antennas.
I have model which consist of the optical antenna on substrate, and I want to calculate scattering cross section and field enhancement.
My question is about sigma (conductivity). Does any of you know what is the difference between case when we put that antenna is perfect electric conductor (sigma = 0), and case when sigma is depend on wavelength of illumination of that structure?
So actually I need some theoretical instructions if any of you is familiar with that.
Regards and thank you
2 Replies Last Post Oct 22, 2012, 1:53 p.m. EDT
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Posted:
1 decade ago
Hi,
A non-PEC will absorb some of the incident power, but you must mesh the conductor properly if you want to get valid results. The mesh must resolve the skin depth at the desired frequency with at least a couple (5-10) of elements. You can search about 'skin effect'.
Cheers
Edgar
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Posted:
1 decade ago
1. A perfect conductor is sigma --> infinity, not zero.
2. For 3D model wave interactions with surfaces of relatively high, but not infinite conductivity, it is often better not to represent the actual surface in-depth because the skin depth is so small and would require such a fine mesh. Instead, it is often sufficient to represent the surface of such a material by means of an "impedance boundary condition." With that setting, the Comsol RF module let's you specify the material properties of the material at the surface, without having to model that material in 3D. This won't tell you the fields inside that material, of course. But the approach is useful in scattering, computing losses, fields on surfaces, modes of cavities bounded by such materials, etc.
2. For 3D model wave interactions with surfaces of relatively high, but not infinite conductivity, it is often better not to represent the actual surface in-depth because the skin depth is so small and would require such a fine mesh. Instead, it is often sufficient to represent the surface of such a material by means of an "impedance boundary condition." With that setting, the Comsol RF module let's you specify the material properties of the material at the surface, without having to model that material in 3D. This won't tell you the fields inside that material, of course. But the approach is useful in scattering, computing losses, fields on surfaces, modes of cavities bounded by such materials, etc.