In hfss, you might have created setup for nearfield or farfield calculations. This can be achieved by (let us say for far field) first creating an infinite sphere with phi varying from 0 deg to 90 deg with a step of 90 deg..ie.for E-plane and H-plane
secondly, theta is varied from -180 to 180 deg with some suitable step (say 2 deg).
this setup is available at HFSS>>Radiation>>Insert far field setup>>infinite sphere.
Then after simulation is completed, again go to HFSS>>Radiation>>compute Antenna/Max params...
Select the "sweep" instead of "last adaptive" to obtain results over a sweep of frequencies.
then proceed, a window will pop-up, showing the calculated antenna parameters that you mentioned. press 0k.
Now to view various results corresponding to your antenna and its radiation characteristics can be seen at
HFSS>>Results>>Create far field report>>your chosen plot.
Following the above you can easily obtain mentioned results.
A request: please do let me know if the results obtained by HFSS following the above steps are in agreement with the results from IE3D at
ashish.sharma@ieee.org. I made this request since i am still a B.tech student who is learning antenna (which is not in my course) on my own so wish to know the results (if you can later post the images of the curves and plots comparing the results from two softwares).
Thanks and Regards