Polyphase filter on Matlab

I am trying to implement the following 4-Tap Polyphase window shown in figure below and used in : polyphase filters- radio astronomy: lecture #8 by Prof. Dale E. Gary on Matlab. Radio Astronomy: Lecture #8. I have tried splitting the window in time domain after multiplication with Sinc function but has not achieved the sidelobe level and mainlobe width shown in green graph- figure on right. I am not sure what I might be missing here. Is there any function that I can create this window (green graph on right).

Many thanks, Sina