Open the FreeCAD software.
(FreeCAD version 0.19 was used, but any version will do)
Click on“New” to create a new project
Select“Part“.
First steps with CAPITOLE-RCS
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The model used is a simple sphere with a radius of 200 mm.
The monostatic RCS calculation will be performed at a frequency of 2.5 GHz on a cross-section in a conical coordinate system at elevation 0° and from -90° to 90° on the azimuth angle with 37 points.
Open FreeCAD software. (FreeCAD version 0.19 was used but any version is suitable)
1. Model creation
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Click on the“sphere” button
Select the“Sphere” object from the tree
Change the radius to ” 0.2 m “.
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Save the project.
In the“File” menu, click on“Export“
Select the“STEP” file format.
For example: sphere200mm.step
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2.define simulation parameters
Run CAPITOLE-RCS (CAPITOLE-RCS version 2.3.9 is used in this document)
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Click on the blue menu, then on“Import” and“CAD file“.
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Select the “ STEP ” file type and select the sphere200mm.step file
In the project panel, set the frequency
Click on the
button Enter a single frequency of 2.5 Ghz
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Create a source
Click on PlaneWave for this source
Create a conical section at elevation 0° and azimuth -90 to 90° with 37 points.
Polarization is horizontal.
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Create an RCS analysis :
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In the Geometry menu, click on“Generate Mesh“.
Leave the default mesh size, which is λ/10.
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The mesh model will be created.
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In the Solver menu, click on“Run“.
Leave default solver“Full
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Click on“Run“
The calculation starts.
The process uses 1.9 GB RAM memory
The calculation takes 36 s on a laptop with an Intel Core i7-7700HQ processor.
When the calculation is complete, click on“POSTPRO” in the“Tools” menu.
The ” sphere200mm ” project will be opened automatically in POSTPRO3D.
Click on the green + sign to the right of the“RCS 1” result to display the monostatic RCS curve as a function of azimuth angle.
A curve can be observed.
The value of around -9dBm² is almost constant over the azimuth, which is close to the theoretical estimate of the RCS of a sphere in the optical region.
σ= πr^2
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