I have tried many ways and read different books and papers but don't find my answer that how to plot a 1D graph of radar with obstacle reflection using MATLAB? I am using the cross-correlation of transmitted and received signal but its not help full..... Also when I export the data of efield from CST its in the form of real and imaginary and when I tried to plot on MATLAB it gives wrong results.
Any suggestions!!!!
You need to do your processing using complex arithmetic - each time sample is a complex number made from the real and the imaginary. Matlab will do this.
When you do cross correlation of two complex signals you multiply one by the complex conjugate of the other, and sum the product over the length of the signal, then do this with different time delays. The result is a plot of correlation against time delay. The range is half the time delay multiplied by the speed of light.
If your signal is periodic then there will be a maximum unambiguous range, and any target at a longer range than half the repeat period multiplied by the speed of light will appear at the remainder left when the true range is divided by the unambiguous range.
If two complex signals are identical and you multiply them together, the resulting number is usually complex, and results from successive samples do not usually have the same phase (vector direction) so don't add up to a large number. If you multiply a complex number by its complex conjugate the product is real, and successive results all add together with the same vector direction and give the maximum possible result. At the delay when the returned signal is a reduced version of the transmitted signal the correlation described above will give a peak value compared to the results at nearby delays. This peak value will reduce with range according to the inverse square law (for voltage).
To get a plot of the data in Matlab you probably need to square real and square imaginary, then add them together (to get power) and plot that against time. You may also want to take the log base 10 of the power, and then multiply by 10 so it is in decibels (dB), which shows small signals much more clearly.
Some processing is possible with power, but it is best to do all the processing with the complex numbers, and only use power or dB on graphs.
Dear Engr Jawad Ali
https://www.mathworks.com/help/phased/ug/radar-equation.html
this link may be helpful
If you try to plot a table of complex numbers in matlab I think it just plots the real part against the imaginary part, so you get a ball of wool! (or something that looks like an explosion).
Change it into power first, and perhaps dB, then plot it against time, or plot the real part against time, or the imaginary part against time. You can't plot a complex number against time unless you do a 3D plot - it is possible to do this and display it as a perspective view, and then parts of it might look like a spring or helical wire. This can be useful in visualising what is happening, rather than looking at two graphs (of real against time and imaginary gainst time), but is a bit complicated.
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