## 5 Comparative Study  
Finally, Table 4 compares the proposed antenna from this work to the MTM-based antennas that have been previously reported in [12; 18; 29; 31; 32; 35] in terms of size, substrate dielectric constant, number of notch-bands, controllability of the notch-band bandwidth and frequency, technique, the complexity of the design, and operational bandwidth. It can be observed from Table 4 that, out of all the antennas presented, nearly all of them are unable to control the notch-bandwidth and frequency. The antenna reported in [12; 18] has a single notch-band with compact size and only the article [18] has demonstrated the feature of controlling only one notch-band bandwidth. The antennas described in [31; 32] provide triple notch-bands based on the MTM technique, but the former lack the benefits of controllable notch-bandwidth and frequency, and the latter have the drawback of a complex design with the option of just one controllable notch-bandwidth and frequency, which is caused by the presence of a varactor diode. The antenna designs indicated in [29; 35] offer a dual notch-band without notch-bandwidth and frequency controllable benefits; the former has a compact size, while the latter has a large size. Most of the antenna designs presented in Table 4 use high-end substrates. In summary, the proposed inverted triangular antenna has the features of low-cost, compact size, and simple design with the option of controllable bandwidth and frequency of the notch and operational band. The main contribution of this paper is that the antenna has features of controllable notch-bands that cover some portion of the C-band and downlink of the X-band satellite communication systems.  
Figure 13: Gain vs. frequency graph of the proposed UWB antenna.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline
**Ref No./Year** & \begin{tabular}{c} **Size** \\ **(mm\({}^{\textbf{\text{\tiny\textregistered}}}\))** \\ \end{tabular} & \begin{tabular}{c} **Substrate** \\ **(v.)** \\ \end{tabular} & \begin{tabular}{c} **No. of Notch** \\ **Band** \\ \end{tabular} & \begin{tabular}{c} **Coverage of** \\ **Bands (GHz)** \\ \end{tabular} & \begin{tabular}{c} **Controllable** \\ **Notch-** \\ **Bands (GHz)** \\ \end{tabular} & \
\begin{tabular}{c} **Controllable** \\ **Notch** \\ **Frequency** \\ \end{tabular} & **Technique** & **Complexity** &
\begin{tabular}{c} **Operational** \\ **Bandwidth** \\ \end{tabular} \\ \hline
[12]/2020 & \(20.5\times 13.9\times 0.012\) & 3.5 & 1 & 7.9-8.4 & No & No &
\begin{tabular}{c} Complimentary- \\ SRR \\ (CSR) \\ \end{tabular} & High & 3.6-19.08 \\ \hline
[18]/2020 & \(16\times 25\times 1.52\) & 2.17 & 1 & 5–6 & Yes & Yes & ERG & Low & 3.1–12.5 \\ \hline
[29]/2021 & \(25\times 35\times 1.6\) & 4.3 & 2 & \
\begin{tabular}{c} 3.11-40.1, \\ 513-5.98 \\ \end{tabular} & No & No &
\begin{tabular}{c} Open meander \\ slitted ERG \\ structure \\ \end{tabular} & Low & 2.63–13 \\ \hline
[31]/2018 & \(36\times 34\times 1\) & 2.65 & 3 & \begin{tabular}{c} 3.97-44.8, \\ 5.79-6.57, \\ 73-20.76 \\ \end{tabular} & \begin{tabular}{c} Only one lower \\ notch band \\ controllable \\ \end{tabular} & \begin{tabular}{c} Only one notch \\ frequency \\ controllable \\ \end{tabular} & \
\begin{tabular}{c} Elliptical and \\ circular ring \\ resonators \\ \end{tabular} &
\begin{tabular}{c} High/Active \\ elements are \\ there \\ \end{tabular} & 3.1–10.6 \\ \hline
[32]/2021 & \(20\times 26\times 1.52\) & 2.17 & 3 & \
\begin{tabular}{c} 3.4-39.5, \\ 5.15-5.82, \\ 72-5.75 \\ 6.2-6.9 GHz \\ \end{tabular} & No &
\begin{tabular}{c} No \\ **No** \\