## 4 Results and Discussion  
The simulated and fabricated results for the antenna incorporating RT/Duroid 5880 materials as the substrate with thickness of 1.57 mm were compared with each other, as shown in Figure 6. The transient solver of the program was used to achieve the desired result. In order to obtain a precise result, the mesh setting was accurately adjusted and the required number of meshes was applied. The network analyzer was used to measure the return loss. It can be seen from Figure 6 that the antenna is well matched and the S11 is about 37 dB. The antenna is a single band operated at 7 GHz with 0.7 GHz (6.7 GHz-7.4 GHz) impedance bandwidth. Similarly, the simulated and measured results for the proposed antenna including RT/Duroid 5880 materials with different thicknesses are shown in Figure 7. The same steps as of antenna A were repeated in order to achieve the best possible results. Figure 5: Image of the fabricated wideband bow-tie antenna. Figure 6: The comparison of simulated and measured return loss of antenna A. One can see from Figure 7 that the simulation result is in accordance with the measured result and the antenna is well matched. However, a small shift can be seen in the operation frequency of the antenna. This might have occurred due to a small scratch in the radiated patch, which occurred during the fabrication process. However, the second antenna, which has is less thick, provided a relatively wider bandwidth, which is around 0.9 GHz (6.7 GHz-7.6 GHz), and the percentage bandwidth is 12.5%, while the percentage bandwidth for antenna A was approximately 10%. The far-field radiation pattern of the antennas could not be measured due to the unavailability of proper device and tools to perform this process. Therefore, only the simulated E plane and H plane radiation pattern of the two antennas are presented in Figure 8. It can be seen from the figure that both antennas provide directional radiation pattern in both planes, while the antenna has a higher side lobe level in E plane of both antennas with a different main lob direction. Antenna B provided a lower side lobe level in the H plane with wider angular of the main lobe compared to that of antenna A.  
Figure 8: The radiation pattern of the proposed antennas (**a**): E plane of antenna A (**b**), H plane of antenna A (**c**), E plane of antenna B (**d**), and H plane of antenna B (**b**). Figure 7: The comparison of simulated and measured return loss of antenna B. In the simulated design and fabricated antenna using RT/Duroid 5880 LZ substrate material with a thickness 0.508 mm and relative permittivity of 1.96, the simulated and measured results for the return loss (S\({}_{11}\) parameters) were recorded, as illustrated in Figure 9.  
Figure 9 shows the simulated and measured results for the return loss (S\({}_{11}\) parameters) when the substrate is yet RT/Duroid 5880 LZ but with thickness of 1.27 mm and same relative permittivity of 1.96. It can be seen from the Figure 10 that both antennas are well matched and the percentage bandwidths of both antennas are almost the same which are 0.13% in both cases (second antenna gives 0.9 GHz (6.5 GHz-7.4 GHz) and first antenna gives 0.92 GHz (6.6 GHz-7.52 GHz)). Antenna B should have been provided a relatively wider bandwidth than that of the antenna A, but this difference was not apparent in the measured result; this could be due to the (SAM) Sub-Miniature version A connection and fabrication tolerances. In addition, it can be observed that this material (\(\varepsilon_{r}=1.96\)) provides better matching and wider bandwidth compared to the RT/Duroid 5880 materials. The far-field pattern of both antennas is presented in Figure 11. The shape of radiation patterns of antenna A and B in both planes are approximately the same. Whereas, the antenna A provide smaller 3 dB angular width of the main lobe with lower side lobe level in comparison with antenna B.