Comparison of Performances of Two Different Antipodal Vivaldi Antennas in Microwave Breast Cancer Detection Systems

In this study, two different antipodal Vivaldi antennas were designed using CST MWS simulation program. The proposed antipodal Vivaldi antennas were designed using 1.6 mm thick FR4 material. The dielectric constant of this material is 4.4 and the loss tangent value is 0.002. The impedance of the feed port is 50 Ω and the copper thickness is 0.035 µm. The compact size of the first antenna is 30 mm x 36 mm, its gain is 5.04 dB and its directivity is 6.48 dB. The size of the second antenna is 38 mm x 33.5 mm, its gain is 7.68 dB and its directivity is 8.77 dB. In the simulation environment, two phantoms were created by placing spherical tumors with two different diameters, each inside a separate heterogeneous breast phantom. Then, the designed antennas in the simulation environment were tested for tumor detection performance on the phantom using the radar-based microwave breast cancer imaging technique (RMWI). After the signal processing stages, tumor images were obtained. In microwave imaging methods, the performance of two different antennas on tumor detection was observed in terms of gain and directivity. In the breast cancer detection study using RMWI technique, the importance of antenna properties such as gain and directivity was emphasized.