After simulation goes to 1D Result, under the tree select  ISI dB and then follow the figure attached.   (Results à  S-Parameter --à  Calculate Z and Y Matrix )

After execution of  Z and Y Matrices return to 1D results now you can see the  Z and Y Matix under 1D results tree (Fig 2).

Thanks a lot, Naresh ... that really helpful. 

I have another question hope you can help me with it as well, I attached a photo for a simple microstrip line which I want to optimise its width to get 100 ohm impedance, I connected it to a 50 ohm resistor at the end of the line. My question is, do I need to normalise the port to 50 ohms and is it correct to terminate the microstrip with 50 ohm load? 

Go to post-processing section and checks-parameter calculation>>calculate z and y matrices.

then look at z-folder in 1d result in the navigation tree.

Thanks a lot, Abdelhadi... I managed to get the impedance vs frequency. I'm now want to make sure that what I'm doing is correct. Could you please check my previous reply on this thread?