## 7 Conclusions
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Ref.** & **Dimension (\(\lambda\lambda\))** & **Bandwidth (GHz)** & **Notching Techniques** & **No. of** & \begin{tabular}{c} **Center** \\ **Notches (GHz)** \\ \end{tabular} & \(\tau_{\text{g}}(\omega)\) **(ns)** & **FF** \\ \hline \multirow{2}{*}{[31]} & \multirow{2}{*}{0.28 \(\times\) 0.28 \(\times\) 0.02} & \multirow{2}{*}{3.1–10.6} & \multirow{2}{*}{Slots on a radiating plane} & \multirow{2}{*}{2} & \multirow{2}{*}{3.5 and 5.5} & \multicolumn{2}{c}{\
\begin{tabular}{c} Constant \\ except \\ band notch \\ \end{tabular} } & \multirow{2}{*}{-} \\ \cline{2-3}  & & & & & & band notch \\ \hline \multirow{2}{*}{[32]} & \multirow{2}{*}{0.22 \(\times\) 0.01} & \multirow{2}{*}{2.63–10.87} & U slot and rectangular & \multirow{2}{*}{2} & \multirow{2}{*}{6.72 and 9.24} & \multirow{2}{*}{<1} & \multirow{2}{*}{0.94} \\  & & split-ring resonator (SRR) & & & & \\  & & on a radiating plane & & & & \\ \hline \multirow{2}{*}{[33]} & \multirow{2}{*}{0.26 \(\times\) 0.17 \(\times\) 0.02} & \multirow{2}{*}{3.1–12.5} & Electromagnetic bandgap on & \multirow{2}{*}{1} & \multirow{2}{*}{5.5} & \multirow{2}{*}{-} & \multirow{2}{*}{-} \\  & & the back of a radiating plane & & & & \\ \hline \multirow{2}{*}{[34]} & \multirow{2}{*}{0.33 \(\times\) 0.28 \(\times\) 0.02} & \multirow{2}{*}{3.08–10.55} & Bandpass filter of & \multirow{2}{*}{1} & \multirow{2}{*}{6.205} & \multirow{2}{*}{<1} & \multirow{2}{*}{-} \\  & & the T-shape & & & & \\ \hline \multirow{2}{*}{[35]} & \multirow{2}{*}{0.18 \(\times\) 0.18 \(\times\) 0.02} & \multirow{2}{*}{3–12} & Circular SRR on a & \multirow{2}{*}{2} & \multirow{2}{*}{5.3 and 7.4} & \multirow{2}{*}{-} & \multirow{2}{*}{-} \\  & & radiating plane & & & & \\ \hline \multirow{2}{*}{[36]} & \multirow{2}{*}{0.20 \(\times\) 0.26 \(\times\) 0.02} & \multirow{2}{*}{3.77–11.64} & S-shaped slot and a pair of & \multirow{2}{*}{2} & \multirow{2}{*}{5.71 and 7.69} & \multirow{2}{*}{
\begin{tabular}{c} Average \\ of 1.36 \\ \end{tabular} } & \multirow{2}{*}{0.78} \\  & & inverted L-shaped stubs on a radiating plane & & & \\  & & a radiating plane & & & \\ \hline \multirow{2}{*}{[37]} & \multirow{2}{*}{0.29 \(\times\) 0.28 \(\times\) 0.02} & \multirow{2}{*}{2.76–11} & Four circular stubs on a & \multirow{2}{*}{2} & \multirow{2}{*}{4.4 and 5.8} & \multirow{2}{*}{<3.2} & \multirow{2}{*}{-} \\  & & radiating plane and two & complementary SRRs on a & & & \\  & & ground plane & & & \\ \hline \multirow{2}{*}{[38]} & \multirow{2}{*}{0.20 \(\times\) 0.26 \(\times\) 0.02} & \multirow{2}{*}{3.73–16.74} & A pair of inverted L-shaped & \multirow{2}{*}{2} & \multirow{2}{*}{7.54} & \multirow{2}{*}{<1.2} & \multirow{2}{*}{0.86} \\  & & stubs on a radiating plane & & & & \\  & & and a C-shaped stub on a & & & & \\  & & ground plane & & & \\ \hline \multirow{2}{*}{[39]} & \multirow{2}{*}{0.33 \(\times\) 0.21 \(\times\) 0.02} & \multirow{2}{*}{3–10.6} & Two slits are engraved on a & \multirow{2}{*}{2} & \multirow{2}{*}{3.5 and 5} & \multirow{2}{*}{-} & \multirow{2}{*}{-} \\  & & radiating plane & & & & \\ \hline Proposed & \multirow{2}{*}{0.19 \(\times\) 0.13 \(\times\) 0.01} & \multirow{2}{*}{3.7–13.3} & Two inverted U-shaped & \multirow{2}{*}{2} & \multirow{2}{*}{5.4 and 7.6} & \multirow{2}{*}{<1} & \multirow{2}{*}{0.94} \\  & & slots on the radiator & & & & \\ \hline \multicolumn{4}{c}{- not available.} \\ \end{tabular}
\end{table} 
Table 5: Performance comparisons with existing structures. substrate length, is responsible for the lower resonating frequency. The dual-band notching is performed by carving two inverted U-shaped slots on the radiator, rejecting the frequency band from 5 to 5.6 GHz and from 7.3 to 8.3 GHz, respectively. The lower and upper notches cover the existing narrowbands such as WLAN, IEEE 802.11/a/b/j/n/ac/ax, and the entire uplink-downlink of X-band satellite communication. In addition to the frequency domain analysis, the projected design is examined for time-domain metrics such as FF, group delay, phase response, and transfer function.