## 5 Application of the Proposed Antenna to the Breast Tumor Sensing  
Owing to the integrated quintuple notched bands for wireless sensor networks, mobile handsets, and the Internet of things (IoT), the proposed compact antenna can be applicable to various portable UWB sensors without severe interruption with aforementioned wireless system. The feasibility of the proposed antenna is investigated in detecting tumor cells in a canonical breast phantom model using the 3D EM simulator, HFSS. As presented in Figure 12, the proposed band-notched UWB antenna is placed at each side of the biological breast phantom model within the frequency range of 3-11 GHz. The model is an inhomogeneous dielectric medium to simulate the human breast by including skin, tissue, and tumor. The breast model utilized in our simulation setup with and without tumor are shown in Figure 12a,b, respectively. The permittivity and conductivity of the skin, tissue, and tumor are given in Table 5, calculated from [42; 43; 44]. The breast tissue layer has been covered with two skin layers, one at the top side and another at the bottom side. The stacked organic layers were scanned by two proposed quintuple notched antennas (one transmitting and the other receiving) with and without tumor cell. After transmitting the UWB pulses with the proposed antenna, the received antenna waveform response is used to detect the tumor cells by comparing the transmitted waveform with and without tumor cells. First, both antennas are placed in a vacuum without placing any stacked layer, and the received waveform is observed. Then, stacked organic layers with and without tumor layer are placed between transmitted and receiving antennas, and the waveform is observed. The combined received waveforms observed in above three cases are presented in Figure 13. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Literature** & **Size (mm)** & **Filtering Bands (GHz)** & **Remarks** \\ \hline \multirow{3}{*}{[36]} & \multirow{3}{*}{33.5 \(\times\) 30} & 3.30-3.70 & Quad notching using multilayered structures \\  & & 4.50–4.80 & Notching is not deep enough for good rejection \\  & & 5.10–5.35 & Antenna structure is complex \\  & & 5.75–5.95 & \\ \hline \multirow{3}{*}{[38]} & \multirow{3}{*}{30 \(\times\) 28} & 3.30-3.36 & \multirow{3}{*}{Quad notching using CSRR structures} \\  & & 4.50–4.70 & & \\  & & 5.15–5.35 & & \\  & & 5.70–5.825 & & \\ \hline \multirow{3}{*}{[39]} & \multirow{3}{*}{80 \(\times\) 80} & 1.85–2.49 & \multirow{3}{*}{Quintuple band-notching with extra rejection bands} \\  & & 2.91–3.40 & & \\  & & 3.95–5.39 & Size of the antenna is relatively large \\  & & 5.65–6.25 & & \\  & & 7.19–8.78 & & \\ \hline \multirow{3}{*}{[41]} & \multirow{3}{*}{31 \(\times\) 25} & 3.40–3.80 & Compact Quintuple band-notched UWB antenna utilizing \\  & & 5.1–5.35 & different slot resonators \\  & & 5.60–6.0 & Irregular placement of the resonators on the patch and \\  & & 7.15–7.65 & ground plane \\  & & 8.05–8.65 & \\ \hline \multirow{3}{*}{This Work} & \multirow{3}{*}{28 \(\times\) 30} & 3.25–3.60 & \multirow{3}{*}{Compact Quintuple band notching with a simple structure} \\  & & 4.40–4.80 & & \\ \cline{1-1}  & & 5.10–5.40 & & \\ \cline{1-1}  & & 5.75–5.95 & & \\ \cline{1-1}  & & 7.50–8.75 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: _Cont._ \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Type** & **Dielectric Constant** & **Conductivity (S/m)** & **Mass Density (kg/m3)** \\ \hline Skin & 36 & 4 & 1010 \\ Tissue & 50 & 7 & 1040 \\ Tumor & 67 & 5 & 1040 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Dielectric properties of the skin, tissue, and tumor. It is seen that the amplitude of the received waveform decreases considerably in case of the tumor layer as shown in Figure 13a, which may lead the conclusion that defected cells are present in the body. The same process is repeated by shifting each antenna 5 and 10 mm away from the stacked organic layers, and the received waveform is observed as presented in Figure 13b,c, respectively.