## 3 Results and Discussion
In order to demonstrate the effect of graphene in one of the graphene-based antenna studies, the study was carried out by choosing copper as the conductive patch part [101]. From the study of [PERSON] et al., it is clear that the return loss peak value is almost twice that obtained with the copper patch (about \(-29\) dB) for the graphene patch [101]. In another study [34], undoped pure graphene is used for the antenna design, and the antenna is modeled in the simulation. Then, different graphene models were created, and the corresponding surface conductors were obtained by applying voltage or adding chemical additives. To test and compare the graphene antenna performance, also, a traditional copper antenna design is prepared. The results showed that the graphene antenna has significant improvements in good reflection, radiation efficiency, and gain compared to the copper antenna. Furthermore, simulation studies for the Antenna-1 structure in this study were repeated for the case in which the conductive part is graphene and copper. As can be seen in Figure 11. Although the geometry is the same, it is seen that the selection in the conductive part affects the antenna performance. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Performance** & \multicolumn{2}{c}{**Designed Bow-Tie Antennas**} & \multicolumn{2}{c}{**Conventional Antennas**} & \multicolumn{2}{c}{**Graphene-Based Antennas**} \\ \cline{2-7}
**Parameters** & **Ant.1** & **Ant.2** & **Ant.3** & **[98]** & **[99]** & **[78]** & **[100]** \\ \hline Return Loss (dB) & \(-38.85\) & \(-34.28\) & \(-29.95\) & \(-32.50\) & \(-64.00\) & \(-25.23\) & \(-39.92\) \\ VSWR & \(1.06\) & \(1.13\) & \(1.00\) & \(1.06\) & \(1.04\) & NR & NR \\ Peak Gain (dBi) & \(9.10\) & \(8.70\) & \(8.90\) & \(5.4\) & \(7.55\) & \(4.83\) & NR \\ BandWidth (GHz) & \(18\) & \(18\) & \(18\) & \(8.2\) & \(8.45\) & \(7.35\) & \(4.0\) \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Performance comparison of previous studies and graphene-based bow-tie antennas designed in this study. Figure 11: The simulation comparison results of the return loss (S\({}_{11}\)) of the graphene-based antenna and copper-based antenna for Antenna-1 in this study. Additionally, the comparison of the antenna produced in this article with the previously studied antennas is given in Table 5.  
Graphene is preferred in antennas due to its many important potentials, such as reducing antenna sizes, providing good integration with electronic circuits, dynamic adjustment possibility, transparency, and flexibility [106]. The most important feature of graphene that makes it usable in antenna applications is the conductivity tensor in its structure [107; 108]. The conductivity tensor depends on many parameters such as temperature, scattering rate, Fermi energy, and electron velocity. The conductivity tensor can be controlled when interacting with static electricity, and magnetic fields from the outside provide a dynamic structure for products made of graphene. Another important feature is that it is frequency-dependent. As the applied electric field increases, the conductivity values increase, but when the frequency rises above 103 GHz in the same electric field, it quickly decreases to zero [109]. Therefore, their conductivity changes according to frequency ranges. Since the frequency range used in this study is between 2 and 20 GHz, graphene is a good conductor in this range. Although copper offers better properties for antenna production, the fact that graphene and PLA can be used with a 3D printer provides a very good advantage in terms of production. [PERSON] and [PERSON] carried out the first graphene-based patch antenna in their study [110]. They produced the antenna patch part from high-rate graphene. The return loss and radiation efficiency of the antenna were investigated, and it was observed that the efficiency decreased due to losses in graphene.