How to set solution frequency of dual band antenna?

Hi all,
I want to simulate a dual band antenna( 2.4~2.484GHz & 5.1~5.8GHz) in HFSS,How to set solution frequency of HFSS?

I would start with a frequency around 4.8 to 5.0 GHz and then do a fast sweep, 2 to 6 GHz, to see what I had.

I would then run additional sweeps in each band with solution frequencies at around 60% of each and again fast sweepsof each band with a little extra on each end.

The next steps would depend on what you find.

my two freq r centred around 12 and 16 GHz ...wht should b the solution freq. and what type of sweep and range of sweep?