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The meaning of electric fiel norm: normE_rfwv ?

Posted 7 set 2011, 12:34 GMT-4 RF & Microwave Engineering 7 Replies

Ronald Hadow
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In the Perpendicular Hybrid-Mode Waves module, does normE_rfwv mean sqrt(Ex^2+Ey^2+Ez^2)?

I tried to test it, it seems that normE_rfwv=sqrt(Ex^2+Ey^2).

Thank you very much for clarifying my confusion!
7 Replies Last Post 29 set 2011, 07:59 GMT-4
Ronald Hadow
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Posted: 1 decade ago 7 set 2011, 15:27 GMT-4
Here is my own answer from test of a simulation.

normE_rfwv (electric field norm) is not the norm that I was thinking about, i.e. it is NOT sqrt(Ex^2+Ey^2+Ez^2), it is NOT sqrt(Ex^2+Ey^2) either.

It is the AMPLITUDE of the TRANSVERSE electric field, or Maximum(sqrt(Ex^2+Ey^2), it does not change with phase. Ez is out of phase with Ex/Ey, so it is not included

Please let me know if I am wrong.
Here is my own answer from test of a simulation. normE_rfwv (electric field norm) is not the norm that I was thinking about, i.e. it is NOT sqrt(Ex^2+Ey^2+Ez^2), it is NOT sqrt(Ex^2+Ey^2) either. It is the AMPLITUDE of the TRANSVERSE electric field, or Maximum(sqrt(Ex^2+Ey^2), it does not change with phase. Ez is out of phase with Ex/Ey, so it is not included Please let me know if I am wrong.
Luca Mussi
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Posted: 1 decade ago 28 set 2011, 11:13 GMT-4
Hi Ronald,
I have an identical problem: I'd like to have a plot of the electric far field norm for a piramidal horn, but according to some test I've made (and to your results), it seems to me that quantity "norm_VARIABLENAME" doesn't work exactly for Euclidean norm (that is what I'm looking for).
I have version 3.5.
Hi Ronald, I have an identical problem: I'd like to have a plot of the electric far field norm for a piramidal horn, but according to some test I've made (and to your results), it seems to me that quantity "norm_VARIABLENAME" doesn't work exactly for Euclidean norm (that is what I'm looking for). I have version 3.5.
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 28 set 2011, 14:57 GMT-4
Hi

in both 3.5 and v4 one can access the internal COMSOl variables (most of them) see the equation sub tab in 3.5 and add the "Equation" sub-node via the parametres in V4.

This is the best place to check our understanding of the variables.

In harmonic solver cases most values are amplitudes, RMS from my knowledge not pk-pk

--
Good luck
Ivar
Hi in both 3.5 and v4 one can access the internal COMSOl variables (most of them) see the equation sub tab in 3.5 and add the "Equation" sub-node via the parametres in V4. This is the best place to check our understanding of the variables. In harmonic solver cases most values are amplitudes, RMS from my knowledge not pk-pk -- Good luck Ivar
Luca Mussi
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Posted: 1 decade ago 29 set 2011, 03:51 GMT-4
Thanks Ivar. I've just searched in "Physics-->Equation System-->Boundary Settings", I've found tangential electric field norm defined as "sqrt(abs(tEx)^2+abs(tEy)^2+abs(tEz)^2)" (so it seems to be an Euclidean norm), but there is no definition for far field variable norm.
My insecurity about the exact expression rised up comparing simple values of single x,y or z component of electric far field vector, with norm value: I mean that if, for a certain point on the boundary where far field variable is defined, x component measures +8 V/m, y component measures +0.05 V/m and z component measures -3 V/m, the norm couldn't be 33 V/m!
Thanks in advance for your attention,

Luca
Thanks Ivar. I've just searched in "Physics-->Equation System-->Boundary Settings", I've found tangential electric field norm defined as "sqrt(abs(tEx)^2+abs(tEy)^2+abs(tEz)^2)" (so it seems to be an Euclidean norm), but there is no definition for far field variable norm. My insecurity about the exact expression rised up comparing simple values of single x,y or z component of electric far field vector, with norm value: I mean that if, for a certain point on the boundary where far field variable is defined, x component measures +8 V/m, y component measures +0.05 V/m and z component measures -3 V/m, the norm couldn't be 33 V/m! Thanks in advance for your attention, Luca
Luca Mussi
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Posted: 1 decade ago 29 set 2011, 05:12 GMT-4
Sorry, double message.
Sorry, double message.
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago 29 set 2011, 07:32 GMT-4
Hi

well its not obvious to give a definitive answer, it also depends how you set your post treatment, many of the plots uses higher order interpolation so this can give collateral effects if i.e. the mesh is not fine enough, you are on an edge of a domain etc

--
Good luck
Ivar
Hi well its not obvious to give a definitive answer, it also depends how you set your post treatment, many of the plots uses higher order interpolation so this can give collateral effects if i.e. the mesh is not fine enough, you are on an edge of a domain etc -- Good luck Ivar
Luca Mussi
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Posted: 1 decade ago 29 set 2011, 07:59 GMT-4
Thank you Ivar.
If it can help you to solve my problem, my model volume consists in two nested spheres with an horn in the centre; I'd like to plot FF on inner sphere edges (in postprocessing mode I use "Domain Plot Parameters-->Line/Extrusion plot"), sphere which meshing tetrahedrons maximum element size is smaller than half-wavelenght.
Thank you Ivar. If it can help you to solve my problem, my model volume consists in two nested spheres with an horn in the centre; I'd like to plot FF on inner sphere edges (in postprocessing mode I use "Domain Plot Parameters-->Line/Extrusion plot"), sphere which meshing tetrahedrons maximum element size is smaller than half-wavelenght.

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