I am working on Antenna with CST and trying to see the near field radiation pattern. But there is only far-field radiation available.
hi
1) see the attach file.
(you have to define E-field and Far-field monitor at the frequency of interest first and run the simulation, once the simulation is done, in the expanded list of Farfield at the Frequency of interest in the navigation tree, select theta patten and show it in Polar from the plot type section in Farfields tab. Then, in resolution and scaling section, choose E-field instead of Directivity .
Finally in the Plot properties section in the far left of the farfields tab select properties then in plot mode tab in reference distance, write the distance you want to show the nearfield patterns from the antenna.
check the use farfield approximation if you want to view the Near field pattern without the radial component. then click Apply.
if you select the Phi under the farfield expanded menu of the frequency of your choice in the navigation tree, the same procedures will apply and you will get the Nearfield Phi pattern as well.
Regards
Mousa
Mousa Abdollahvand has given a good and helpful answer.
In addition, you have talked about the near-field radiation pattern. The near-field radiation pattern can mean many things. It changes with distance from the antenna, in strength and in shape. It is possible to obtain a radiation pattern at any range using a transform similar to a Fourier transform, from the far-field back to a plane in the near-field. The far-field pattern is the Fourier transform of the fields in the aperture plane, and the fields in the aperture plane are the inverse transform of the fields in the far-field.
If you want the variation of power with angle, as in the far-field, you have to define where the centre is, because this affects the angle in the near-field but not in the far-field.
If you want the radiated fields in the near-field, then you will need to define the points at which you want them, and perhaps separate out the radiated fields from the reactive fields, which exist in the near field but don't produce any radiation.
If you want the near-field pattern to illuminate a dish, for example, then this is usually beyond the reactive fields.
CST will save near-fields on a box surface to use as the feed for another part of an antenna. Search for near-field in help.
Dear Colleague,
hope this will help
https://www.cst.com/Products/CSTMWS/TechnicalSpecification
You can't have near-field gain, unless you change the definition of gain, which is defined in the far-field of an antenna, and doesn't change with distance from the antenna.
No. It means if you want to use gain in the way you want, you have to mean something different by gain to what all the design equations and codes mean by gain. You would not be able to use it to give a correct answer in any of the formulae using gain that are usually used.
Gain means what is measured in the far-field, not what is measured in the near-field.
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