resonant frequency of microstrip patch antenna

Hi, i am trying to find resonant frequency of microstrip patch antenna has (for patch width=57 mm length=38mm, for substrate h=3.175mm permittivity=2.33 ) parameters, which solution frequency should i define to add solution setup?
By the way i am checking rectangular plot (S_11) to see resonant frequency,does driven modal or driven terminal solution type make more clear report?