You can use Matlab /STCompose/Excel to create an ascii file (txt), two columns, with the raised cosine profile. Then get the file import and use it to generate the curve inside the EM simulation tool.

You can also use the "Analytical Curve" feature in CST.

For example, in the CST modeling tab, click on Curves->Analytical Curve. This brings up a dialog box in which you can enter parametric formulas for a curve in 3d space. I entered a raised cosine profile as you can see in step1.jpg. The outcome is shown in step1_result.jpg.

I chose to revolve this profile around an axis (you could also extrude or loft, depending on your intentions). To do this, you have to create another curve as the sweep path. For this I just created a circle (Curves->Circle). See step2.jpg for my entries, and step2_result.jpg. Be sure that you select "New Curve" under the "Curve:" drop-down menu in this dialog box, you want the cosine profile and the sweep path to be separate curves.

Finally, select Curve Tools->Sweep Curve. Then choose the cosine profile as the profile to sweep, and the circle as the path curve. See step3_result.jpg.

Hope this helps!

Matt

Hello,

There is well defined function to use raised cosine to form non linear cylindrical taper. First, to draw full structure, we should have radius of both ends, total length and point between both ends. these points can be calculated using MATLAB, by applying the raised cosine function. These points actually come because of variation in angles at the edge of taper. Another method to get these points is CST itself, where just by giving the function as a command, will give all points.When points, radii and length ready, then easily structure can be designed. Put all the points in note pad from one end to another end, then open CST, and use the command which will ask you datas (points) first, then load the save points, and click ok to draw. There are several papers are available in this particular topic.

Thanks,

Hi Matthew,

How I can fill this shape with material?

Thank you!

Iris

Hi Iris,

Thank you for asking, I realized that my original answer lacked that particular detail.

To create a solid shape, the curve you sweep has to be closed. In this case, you can do that by adding three line segments to the swept curve. Those segments should join both ends of the cosine profile. See "line_segments.png"

Note that the line segments are part of the same "curve" as the cosine taper, namely "curve1". See "closed_curve.png"

When you add the circle as the sweep path, put that in a new curve, "curve2". See "both_curves.png"

Finally, perform the sweep, selecting the now-closed curve1 as the swept curve, and the circle curve2 as the sweep path. You should now have a solid shape. See "after_sweep.png"

I hope this helps!

Matt

Thanks!

Actually I've found anouther solution: drawing two circles and connecting between them with analytical curve, and then using the "loft curves" function.

Appreciate your quick answer,

Iris

My pleasure. Nice that you found an alternate solution --- it's always good to have more than one approach!

Matt