Planar Slot Antenna Backed by Substrate Integrated Waveguide Cavity

I wish to design a substrate integrated waveguide slot antenna. I have designed the antenna using hfss15.0 software. But my solutions are not matching with the original solutions of the paper. I am hereby attaching my .hfss file of my project and also the paper that I am following. I am new in this domain and I am not getting the desired results. Please help me regarding this. Immediate help would be greatly appreciated.