## 4 Results and Discussion  
A 3D scanning device was built that allows one to send signals to the phantom and receive the reflected signals. A simple mechanism consisting of a 50 mm radius hemispherical plastic container suitable for scanning in the prone position was set up. The setup was completed by leaving the breast phantom in the plastic cap. Homogeneous and heterogeneous breast phantoms were prepared for measurements in the experimental setting. The homogeneous phantom consists of fat and a tumor. The heterogeneous breast phantom consists of skin, fat, glands, and a tumor. The proposed Vivaldi antenna was produced for the receiver and transmitter sensors to be used in the experimental environment. In experimental environments, tumor detection capacity depends significantly on the characteristics of the VNA device used. The dynamic range of the device is of great importance in this regard. Therefore, tumor detection capacity is not as high as in the simulation environment. In experimental settings, it is difficult to detect tumors in phantoms containing glandular tissue because this tissue weakens the tumor response [53]. Therefore, heterogeneous and homogeneous phantoms were used for tumor detection. The procedure for preparing homogeneous and heterogeneous breast phantoms with the tumors that we used was employed [72, 97]. Unlike this procedure, in this study, powdered bovine gelatin and \"Fairy\" washing detergent with the same properties were used as surfactants [53]. The quantities of components required to construct the breast phantoms are shown in Table 4.  
The diameter of the phantoms was 100 mm, and a tumor with a diameter of 16 mm was placed inside the phantom. Since the dynamic range of the VNA used in the experimental setting was not high enough to detect very small tumors (maximum 83 dB), we kept the tumor size large in stage-one breast cancer (the tumor size in stage 1 can be a maximum of 20 mm). During the production phase of the phantoms, a tumor was first created and allowed to solidify. After the tumor was created in the homogeneous phantom, an oily phantom was made into a plastic bowl and left inside the tumor. In the heterogeneous phantom, skin tissue (2 mm) was first made into a plastic bowl, and after it solidified, 35% fat tissue was added. Finally, the phantom was produced by adding glandular tissue and the tumor (16 mm diameter). All phantoms were left to solidify for 2 days. The phantoms were removed from the mold after solidification. In the measurements, a 16 mm tumor was detected in homogeneous and heterogeneous phantoms. Figure 10 shows the phantom construction stages. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Material** & **Fat** & **Gland** & **Skin** & **Tumor** \\ \hline p-toluic acid (g) & 0. 133 & 0.253 & 0.294 & 0.346 \\ n-propanol (mL) & 6.96 & 12.71 & 28.69 & 17.0 \\ Deionized water (mL) & 132.7 & 241.9 & 279.5 & 328.0 \\
200 Bloom gelatin (g) & 24.32 & 43.27 & 50.02 & 58.67 \\ Formaldehyde (37\% by weight) (g) & 1.53 & 2.74 & 3.33 & 3.72 \\ oil (mL) & 265.6 & 141.5 & 98.6 & 8.4 \\ Washing detergent (mL) & 12.00 & 6.79 & 5.86 & 2.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Proportions of tissues used in the phantom. In the proposed radar system, the Vivaldi antenna is used as a transmitter and receiver. The radar system is shown in Figure 11. Using the VNA's time domain feature, a Gaussian signal was automatically sent and the reflected signals were recorded. The signals recorded in the VNA were transferred to a computer for the signal processing stage. The filtering technique specified in Equation (4) in the previous section was not used in the signal processing stage. Since it is not possible to measure breasts with and without tumors at the same time, they are not suitable for real applications. An adaptive Wiener filter was used as the filtering technique. The signals collected with this filtering technique were calibrated [59].