theory result vs semulated for o.c microstrip line

hi
i simulated following project and got this result :
s11=(0.99573,98.7)
z0=20.124
gamma=60.956

every simulated results match to theorical answers bur s11, best regardsMicrostrip line.rar

and from transmission line theory whats effect of z0
i mean does its effect is like s11=(zIN-z0)/(zIN+z0)
thank for you patient dear friends

no answer ?

is this so difficult or easy?!