s11 in microstrip patch antenna

hi
i am simulating a microstrip patch antenna in HFSS,excited by a coax,but i can not get the s11 in the paper.mine is about half of the one in the paper.please help me,what is the reason?!

attach file and only then ppl can help u

I wanted to attach the file but the error "The Extension hfss is not allowed" appeared.what shall I do?!

zip it or rar.

Thanx! :D Here it is.