[SOLVED] 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

The bandwidth of an antenna is defined as the range of frequency over which the VSWR is "still acceptable". Generally values of VSWR=1.5 or even VSWR=2.0 are used. The return loss (that reported in your picture) is given by:

RL=20*Log[VSWR/(VSWR-1)] that means:

VSWR=1.5 ==> RL = -6dB
VSWR=2.0 ==> RL = -10dB

In the first case the range of frequency is 4.8-7.4 GHz ==> BW=2.6 GHz
In the second case the range of frequency is 5.2-7.1 GHz ==> BW=1.9 GHz

Thank you freind , it was helpful