Antenna Bandwidth computing

Hello everybody

I want to know how we can compute antenna bandwidth from this curve ?
please if any of you know help me

Thank you all in advance

The bandwidth for RL > 10 dB in this curve is 1.9 GHz (i.e. from 5.2 GHz to 7.1 GHz).

(This is only the impedance matching bandwidth. There are other performance indicators also which you might want to consider.)

Thank you very much for the time you took to help me :))

Its also worth to check the gain in this frequency range to make sure that your antenna radiates.
The S11 only shows a good match, but not what happens with the energy!