Excitation of substrate integrated waveguide with taper

I am simulating a transformer using substrate integrated waveguide. The results are confirmed with an analytical solution using equations and plotted in Matlab. To get the correct results using HFSS I should use "Zwave" for the characteristic impedance (Zo) in the wave port excitation after renormalizing the full port impedance to the desired one. When I use the microstrip transition taper and apply the wave port excitation on "Zpi" or "Zpv" as we do for the microstrip case the results seem to be not what I am expecting, I got the expected results as in Matlab only when I use "Zwave". Can I use "Zwave" for exciting a microstrip port?

What makes me confused and not sure for the result of "Zwave" is that when I simulated a microstrip port with a width gives 50 ohms and draw the port impedance, I got 50 ohms for when I used "Zpi" or "Zpv", whereas "Zwave" gives me a value of 220 ohms approximately!! So what is the main difference between "Zwave" and "Zpi"?

Thank you in advance!