Fig. 8 shows the gain comparison between the simulated
and measured results of the split-ring rectangular slot
antenna. The measurement results were used to calculate the
antenna gain frequency was ploted in Fig. 8. The gain over
operating frequency at start frequency band 1.0 GHz is
obtained -8.2 dBi, at the operates frequency are obtained 6.8
dBi and 6.9 dBi for 2.45 GHz, 5.2 GHz band, respectively,
at stop frequency band 8.5 GHz is obtained 7.2 dBi. The
result illustrates that this antenna has the good gain, and
maximum gain is 8.5 dBi at 6.5 GHz.