## 3 Fabrication of the Proposed Bow-Tie Microstrip Antenna  
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 \(\Omega\) input impedance waveguide port. The two triangular shapes were exactly similar, while their substrate thickness was different.  
The fabricated antennas with 50 \(\Omega\) SMA (Sub-Miniature version A) connectors are shown in Figure 4. The positive pin of the SMA connector 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 connector and it behaves as a negative junction. The dimensions of both fabricated antennas are shown in Tables 1 and 2, respectively.  
In addition, two more antennas were designed by using RT/Duroid 5880 LZ material with different thicknesses. Both antennas have a relative permittivity of 1.96 with a substrate thickness of 0.508 mm and 1.27 mm, respectively. The required dimensions for the fabrication process are shown in Tables 3 and 4, respectively, while the physical presentation of the antennas with SMA connectors are shown in Figure 4.  
The proposed wideband bow-tie antenna has been fabricated two times with the same materials but in different thicknesses. For more precise results, the width and length of the antenna were considered to be 54 mm and 80 mm by using an E33 model LPKF stands for \"Leiterplatten-Kopierfrasen\", which when translated means \"circuit board copy milling\" prototyping printed circuit board (PCB) machine. This is where a single-sided substrate covered with copper of a constant thickness of 35 micrometers was used. The thicknesses of both fabricated antennas were 0.508 mm and 1.27 mm, respectively. All required dimensions are shown in Table 5. After the fabrication of the antenna, a 50-Ohm SMA connector has been soldered to the feeding line, as illustrated in Figure 5. The experimental study has been achieved via a PNA-L Agilent vector network analyzer (VNA) with an operating frequency ranging from 10 MHz to 43.5 GHz. The VNA was first calibrated by using the proper calibration kit having short circuit, open circuit and load apparatus. The calibration of VNA was realized in the operating frequency range of antenna and this range was between 4 GHz and 8 GHz. Finally, the antenna has been connected to the VNA and the return loss parameter, gain and radiation pattern were measured.  
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.