Fig. 5 Comparative analysis of the simulated reflection coefficients (|S11|) of iteration five and six.
Hence, to move the center of notch frequency fromfns1= 4.7 GHz to fn =5.5 GHz with the notch band from 5 GHz to 6 GHz, an SRR is introduced in the left side of the microstrip feed line in the iteration six depicted in figure 4 (b). After introduction of the SRR in the left side of the microstrip feed line the bandwidth is enhanced from 3.097GHz to 13.326GHz with the impedance bandwidth of 10.23 GHz which is highest among all the impedance bandwidths of previous five iterations. The percentage of bandwidth of the proposed UWB notch antenna is 125%. At the same time the center of the notch frequency of iteration fivefns1= 4.7 GHz is shifted right tofn =5.5 GHz with notch band from 5 GHz to 6 GHz which is the desired center of the notch frequency for mitigation of interference between the WLAN and UWB band of operation.
The shifting of notch frequency fns1= 4.7 GHz tofn =5.5 GHz is due to the presence of the SRR on the left side of the microstrip feed line. As we know that the SRR is a resonating structure, the resonance characteristics of a unit cell split ring resonator (SRR) are shown in figure 6.