Hi everyone,
I've got an antenna pattern in CST MWS that I want to transfer to Matlab for further edits in order to put it in the paper. But unfortunately, when I export from CST and import it to Matlab there is something wrong and I can't get the exact pattern in Matlab.
This is the procedure I perform:
1-Exporting ASCII file of the 2D pattern of the antenna from CST
2-Running the following code in Matlab:
load('LWA6200.txt');
p=LWA6200(:,3);
t = 0:0.0175:2*pi ;
polar(t,p');
But comparing the attached images number 1 (CST) & number 2 (Matlab) shows the difference!!!
So, firstly what's wrong with my code and secondly what's the best way of transferring the 2D pattern into Matlab from CSTMWS??
Every help would be appreciated...
Something is going wrong during the import...
Try using the "importdata" function. There you have more options like the delimiterIn as the column separator in ASCII file:
https://www.mathworks.com/help/matlab/ref/importdata.html
Matlab is plotting it correctly. You have given it the wrong axes, or you haven't bothered to specify the axes correctly. What range of values do you expect to plot? Look at the axes!
Nothing has gone wrong with the import. Matlab has imported the correct values, and is displaying them as you have asked (allowed) it to.
This is actually what I got from CST. I just want to have the exact 2D pattern in Matlab. This is the Farfield Gain and the values are in dB.
The plot you have allowed MATLAB to display has 0 dB at the bottom and goes up to 60 dB at the top. How do you expect to see values that go from 10 dB down to -60 dB? MATLAB is doing its best with the what you have given it. Tell it sensible values for the axes and it will give you the display you would like.
Hi,
since the polar plot uses only positive values for rho, you have to shift you imported data to a positive range, and then you can label the rho-axis on your own. This is possible with:
p_min_axis = round((min(p)-5)/10)*10;
p_max_axis = round((max(p)+5)/10)*10;
polarplot(t,p'-p_min_axis);
ax = gca;
ax.RTick = 0:20:90;
ax.RTickLabel = {p_min_axis:20:p_max_axis};
For example, p_min_axis ensures a round minimum limit at -60dB instead of -52dB. Your data is shifted to a positive range, then a new axis label is set.
Regards
Robert
I don't think that is the problem. MATLAB can't display your polar diagram correctly when the radial axis runs from 0 to 60 dB. You need to plot from -60 to 10 dB. YOU need to set the radial axis scale correctly. If you have the centre as 0 dB, anything below 0 dB gets plotted on the other side of the centre and looks very strange. There is nothing wrong with your data file, and nothing wrong with MATLAB, you have set the radial axis to the wrong range to display the data you have given it. It is usual, when you plot data, to set the axes ranges so that they are correct to display the data. Why haven't you done that?
Dear Malcolm White ,
Actually, I didn't know I could scale the range of axes. I just found out there is a ability as Polaraxes function to change the scales of axes by "ThetaLim" and "RLim" in Matlab for the version of 2016a and higher. However, mine is 2014a version. So, I'm looking for the proper code to do so...
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