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farfield pattern in 2D axisymmetry

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hi,
I just tried to simulate a simple circular waveguide antenna in 2d axisymmetric RF module. I followed same procedure as the application model (Corrugated Circular Horn Antenna) in RFmodule. actually I have 3 questions.
1- how can I export the 3D farfield pattern based on theta, phi, r and also Etheta, Ephi , Er.... I mean spherical coordinate.I wonder it is based on x, y , z !!!
2- I don't understand the matter of m-angular.Is it necessary to be set because of circular waveguide and 2d axisymmetry? I can not confirm the result with a CST simulation of the same structure.
3) A usual way to see the level of cross polarization of an antenna is to use Ludwig definition. It is a formula of Etheta and Ephi. firstly this is not possible in comsol( no varaible theta and E theta is in 2D axisymmetry), second, when I export the 2D plot of farfield E and then import them to matlab to combine Er and Ephi for achieving Etheta and then combining it to achieve Ludwig definition of cross pol I get wrong results.
in 2D plot of farfield when I change the normal to (1 ,0 ,0) or (1, 1, 0) the peak goes to phi=90. I don't understand why ?

I can upload my file for you if it is necessary. I increase the number of meshes. I draw a bigger circle as the entire domain but non of them were helpful.

0 Replies Last Post 21.10.2015, 05:25 GMT-4
COMSOL Moderator

Hello Parastoo Taghikhani

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