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Figure 1. The design geometry of antenna A and B with same RT/Duroid 5880 materials substrate and different substrate thickness.

Figure 1 The design geometry of antenna A and B with same RT/Duroid 5880 materials substrate and different substrate thickness.

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Table 1. Antenna A parameters.
Table 1. Antenna A parameters.
Figure 2. Design of the geometry of antenna A and B with same substrate RT/Duroid 5880LZ material and different thickness. Table 3. Antenna A parameters.
Figure 2. Design of the geometry of antenna A and B with same substrate RT/Duroid 5880LZ material and different thickness. Table 3. Antenna A parameters.
Table 2. Antenna B Parameters. 2.2. Antenna Design by Using RT/Duroid 5880LZ Material In the second stage, two different antennas were designed and fabricated using the same materials but different thicknesses. This material has a lower relative permittivity and thicknesses than that used in Section 2.1. Again, to avoid confusion during comparison and analysis of the results, the first antenna is named antenna A while the second one is antenna B.
Table 2. Antenna B Parameters. 2.2. Antenna Design by Using RT/Duroid 5880LZ Material In the second stage, two different antennas were designed and fabricated using the same materials but different thicknesses. This material has a lower relative permittivity and thicknesses than that used in Section 2.1. Again, to avoid confusion during comparison and analysis of the results, the first antenna is named antenna A while the second one is antenna B.
Figure 3. The geometry of the proposed broadband antenna. In this stage, by introducing a small sector stub near the feed line and bending the corners of both triangular shapes, the wideband bow-tie antenna is designed and simulated. This small sector plays an important role in increasing bandwidth because the current is strengthened around the stub, which acts upon improving the electric field distribution. Bending the corners of the stub and presenting both triangular patch shapes are participating in the enhancement of the bandwidth [1]. The antenna was refabricated on different substrate thicknesses in order to optimize its performance and hence obtaining better results. The geometry of the designed antenna is shown in Figure 3, while the dimensions of the antenna and slots are presented in Table 5.
Figure 3. The geometry of the proposed broadband antenna. In this stage, by introducing a small sector stub near the feed line and bending the corners of both triangular shapes, the wideband bow-tie antenna is designed and simulated. This small sector plays an important role in increasing bandwidth because the current is strengthened around the stub, which acts upon improving the electric field distribution. Bending the corners of the stub and presenting both triangular patch shapes are participating in the enhancement of the bandwidth [1]. The antenna was refabricated on different substrate thicknesses in order to optimize its performance and hence obtaining better results. The geometry of the designed antenna is shown in Figure 3, while the dimensions of the antenna and slots are presented in Table 5.
Table 5. The antenna and slot diminutions.
Table 5. The antenna and slot diminutions.
Table 4. Antenna B parameters. 2.3. Design of a Broadband Bow-Tie-Based Antenna
Table 4. Antenna B parameters. 2.3. Design of a Broadband Bow-Tie-Based Antenna
Figure 4. Fabricated bow-tie (a) antenna A with a thickness of 1.57 mm and 0.508 mm, (b) antenna B with a thickness of 3.175 mm and 1.27 mm. The proposed bow-tie antenna for UWB applications has been fabricated as illustrated in Figure 4. Basically, the antennas are designed to be operated at 7 GHz, which is relatively the center of the UWB frequency band. However, the designs can be easily modified in order to tune the operation frequency for various UWB applications. The materials used in the fabrication of bow-tie microstrip are RT/Duroid 5880 and RT/Duroid 5880, while considering different thicknesses. In the first stage of the fabrication process, RT/Duroid 5880 was used in two different thicknesses (1.57 mm and 3.175 mm) with a relative permittivity of about 2.2. In the design of both antennas, the two microstrip lines were used to excite the antenna with 50 O input impedance waveguide port. The two triangular shapes were exactly similar, while their substrate thickness was different. The fabricated antennas with 50 Q SMA (Sub-Miniature version A) connectors are shown in Figure 4. The positive pin of the SMA connecter is soldered with the right triangular patch, which behaves as a positive terminal. While the left triangular patch is connected to the ground of an SMA connecter and it behaves as a negative junction. The dimensions of both fabricated antennas are shown in Tables 1 and 2, respectively.
Figure 4. Fabricated bow-tie (a) antenna A with a thickness of 1.57 mm and 0.508 mm, (b) antenna B with a thickness of 3.175 mm and 1.27 mm. The proposed bow-tie antenna for UWB applications has been fabricated as illustrated in Figure 4. Basically, the antennas are designed to be operated at 7 GHz, which is relatively the center of the UWB frequency band. However, the designs can be easily modified in order to tune the operation frequency for various UWB applications. The materials used in the fabrication of bow-tie microstrip are RT/Duroid 5880 and RT/Duroid 5880, while considering different thicknesses. In the first stage of the fabrication process, RT/Duroid 5880 was used in two different thicknesses (1.57 mm and 3.175 mm) with a relative permittivity of about 2.2. In the design of both antennas, the two microstrip lines were used to excite the antenna with 50 O input impedance waveguide port. The two triangular shapes were exactly similar, while their substrate thickness was different. The fabricated antennas with 50 Q SMA (Sub-Miniature version A) connectors are shown in Figure 4. The positive pin of the SMA connecter is soldered with the right triangular patch, which behaves as a positive terminal. While the left triangular patch is connected to the ground of an SMA connecter and it behaves as a negative junction. The dimensions of both fabricated antennas are shown in Tables 1 and 2, respectively.
Figure 5. Image of the fabricated wideband bow-tie antenna.
Figure 5. Image of the fabricated wideband bow-tie antenna.
Figure 6. The comparison of simulated and measured return loss of antenna A. The simulated and fabricated results for the antenna incorporating RT/Duroid 5880 materials as the substrate with thickness of 1.57 mm were com pared 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 bandwidt nN.
Figure 6. The comparison of simulated and measured return loss of antenna A. The simulated and fabricated results for the antenna incorporating RT/Duroid 5880 materials as the substrate with thickness of 1.57 mm were com pared 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 bandwidt nN.
Figure 7. The comparison of simulated and measured return loss of antenna B. 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%.
Figure 7. The comparison of simulated and measured return loss of antenna B. 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%.
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). 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). lobe level in the H plane with wider angular of the main lobe compared to that of antenna A.
Figure 9. The simulated and measured return loss of antenna A with thickness of 0.508 mm. 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|; parameters) were recorded, as illustrated in Figure 9.
Figure 9. The simulated and measured return loss of antenna A with thickness of 0.508 mm. 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|; parameters) were recorded, as illustrated in Figure 9.
Figure 10. The simulated and measured return loss of antenna B with thickness of 1.27 mm. we here 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 whic gives 0.9 GHz (6.5 GHz-7.4 GHz) and first antenna gives h are 0.13% in both cases (second antenna 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 (¢, = 1.96) provides better matching and wider bandwidth compared to the RT/Duroid 5880 materials.
Figure 10. The simulated and measured return loss of antenna B with thickness of 1.27 mm. we here 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 whic gives 0.9 GHz (6.5 GHz-7.4 GHz) and first antenna gives h are 0.13% in both cases (second antenna 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 (¢, = 1.96) provides better matching and wider bandwidth compared to the RT/Duroid 5880 materials.
Figure 11. 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.
Figure 11. 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.
Figure 12. Realized gain of the proposed antennas versus the frequency in the range of interest The realized gain over operating frequency range of the four antennas is plotted in the Figure 12. As can be seen from the figure, the antenna with lower relative permittivity of 1.96 provided higher gains, while when the substrate thickness is increased to 3.175, the gain also increased. Therefore, it can be said that the realized gain is inversely proportional with relative permittivity and directly proportional with substrate thickness.
Figure 12. Realized gain of the proposed antennas versus the frequency in the range of interest The realized gain over operating frequency range of the four antennas is plotted in the Figure 12. As can be seen from the figure, the antenna with lower relative permittivity of 1.96 provided higher gains, while when the substrate thickness is increased to 3.175, the gain also increased. Therefore, it can be said that the realized gain is inversely proportional with relative permittivity and directly proportional with substrate thickness.
Figure 13. Simulated axial ratios of the antennas over the frequency range of interest. Finally, the polarization of the four antennas was monitored. For this purpose, the axial ration of the antennas was plotted in Figure 13. Based on the 3 dB criteria, all antennas provided circular polarization, while an improved circular polarization was obtained from the antennas with relative permittivity of 1.96 and 2.2 with a substrate thickness of 1.275 and 3.175, respectively. As demonstrated in the previous sections, the proposed antennas have a relatively narrow bandwidth. Therefore, broadband bow-tie slot antenna was designed, fabricated and tested The measured result is compared with the simulation result. The fabricated antenna is measure by the VNA network analyzer. The network analyzer is calibrated by using a calibration tool in order to get more precise results, such as open, short and broadband loads. The simulated and measured return losses are plotted in Figure 14.
Figure 13. Simulated axial ratios of the antennas over the frequency range of interest. Finally, the polarization of the four antennas was monitored. For this purpose, the axial ration of the antennas was plotted in Figure 13. Based on the 3 dB criteria, all antennas provided circular polarization, while an improved circular polarization was obtained from the antennas with relative permittivity of 1.96 and 2.2 with a substrate thickness of 1.275 and 3.175, respectively. As demonstrated in the previous sections, the proposed antennas have a relatively narrow bandwidth. Therefore, broadband bow-tie slot antenna was designed, fabricated and tested The measured result is compared with the simulation result. The fabricated antenna is measure by the VNA network analyzer. The network analyzer is calibrated by using a calibration tool in order to get more precise results, such as open, short and broadband loads. The simulated and measured return losses are plotted in Figure 14.
Figure 14. The simulated and measured return losses of the slot antenna (thickness = 1.27 mm)
Figure 14. The simulated and measured return losses of the slot antenna (thickness = 1.27 mm)
Figure 15. The simulated and measured return losses of the slot antenna (thickness = 0.508 mm). From Figure 15, it can be noted that more accurate result was obtained because the measured result is highly correlated with the simulation result. The measured return loss is around —25 dB and the obtained bandwidth is about 1.4 GHz, which is about 22% (obtained bandwidth is 1.3 GHz with 5.65 GHz lower and 6.95 GHz higher frequency limits). Again Arto tr tho arailahniltt; nf tho davwiroc tho farfiold nattorn tie nat moacirod
Figure 15. The simulated and measured return losses of the slot antenna (thickness = 0.508 mm). From Figure 15, it can be noted that more accurate result was obtained because the measured result is highly correlated with the simulation result. The measured return loss is around —25 dB and the obtained bandwidth is about 1.4 GHz, which is about 22% (obtained bandwidth is 1.3 GHz with 5.65 GHz lower and 6.95 GHz higher frequency limits). Again Arto tr tho arailahniltt; nf tho davwiroc tho farfiold nattorn tie nat moacirod
Figure 16. The radiation pattern of the bow-tie slot antenna (a), E-plane and H-plane (b). Again, due to the availability of the devices, the far-field pattern is not measured. Therefore, only the simulated far-field pattern is presented in Figure 16.
Figure 16. The radiation pattern of the bow-tie slot antenna (a), E-plane and H-plane (b). Again, due to the availability of the devices, the far-field pattern is not measured. Therefore, only the simulated far-field pattern is presented in Figure 16.
Related topics:
PhysicsMaterials ScienceMicrostrip AntennaBow TiePATCH ANTENNA
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