Fig. 6 Simulated reflection coefficients (|S11|, |S21|,) of unit cell split ring resonator (SRR).
From the graph it is clear that the SRR resonates at resonating frequency of fns2= 6.1 GHz. Because of the presence of the SRR in its position in the proposed UWB antenna, the actual simulation notch frequency is found to be
\(f_{\text{ns}}=\frac{f_{ns1}+f_{ns2}}{2}=\frac{4\cdot 7GHz+6\cdot 1GHz}{2}=5\cdot 4GHz\)———————————–(3)
But in simulation of the proposed UWB antenna the notch frequencyf n is found to be 5.5 GHz which is close to the desired notch frequency f n =5.5GHz obtained in iteration six. Hence the difference of f ns andf n is due to the different simulation environment adopted for SRR in the proposed notch antenna as single unit cell. Apart from this, the difference of f ns andf n may be due to the extra electromagnetic coupling between the SRR and microstrip feed line. In overall it is clear that the presence of SRR in the left side of the proposed antenna the notch frequency of iteration six, the initial notch frequency i.e.f ns= 4.7GHz obtained at iteration four is shifted to the notch frequency of the proposed UWB notched antenna i.e.f n=5.5GHz which is shown in the figure 6 (iteration six).