You need to use something like 'Projection' feature. I am not sure where it is in HFSS, but I can create for you such a file in EMCoS Virtual AntennaLab. Attached is similar SAT file (you can load it in HFSS) - specify your dimensions, I'll generate what you need.
We can also compare simulation results, if I'll have some time to simulate it as well. What is frequency range? What you are looking for - S11, patterns? Or what publication you are referencing by this model?