Dear Adamu

Please follow this process: save ASCII data file from CST import option (.txt)------> open it into excel--------> place it into origin----> plot it

The ASCII data file contains varying angle theta/phi, constant angle for E- and H-plane, absolute values, phi amplitude values, phi phase values, theta amplitude values, theta phase values, axial ratio. You can consider the phi and theta values for E- and H-plane at constant angles depending on the orientation of the structure.

hope you find the answer.

https://www.eit.lth.se/sprapport.php?uid=804

First you can export data just for Polar, Cartesian or 2D diagrams, 3D NOT included. When a polar Radiation pattern is displayed you go to Home > Copy, now you can paste your data anywhere to make some modifications, for example in Excel, then try to map the angle values to a reasonable values' interval if necessary, for example if Phi is varying as follow:

0, 1, ....,178, 179, 180, 179, 178, ..., 2, 1, 0

so you have change it to:

0, 1, ..., 178, 179, 180, 181, 182, ..., 360

Then copy-past your actual values into Origin Lab. In excel there is no way how to plot a polar diagram as I know.