# Monitoring of Surgically Treated Upper Arm Fracture by Implanted Antenna at 402 MHz
## 5 Measurement and Validation  
In this paper, the front leg of a lifeless animal was chosen for carrying out the experimental measurements. It should be mentioned that the model used in the experiments is a fresh front leg of a cow and it was procured from a local butcher for normal consumption, so no animals were harmed specifically for this study. This model was selected to be close in composition to human arm tissues. However, there is a difference in the amount of blood between the non-living model and the human arm. The system shown in Figure 11 consists of a vector network analyzer NanoVNA-F V2, SMA cable of connecting the antenna and the VNA, \(116\times 5\) mm\({}^{2}\) planar, and 120 mm wire half-wave dipole antennas, the animal model, medical splint, fixation plate, and a computer. In surgical treatment of such fractures, first the surgeon cuts the skin and muscles to move the bone back into the normal position. Second, a metal rod, screws, and plates are attached to the bone to hold it. Finally, the surgeon closes the incision with stitches or staples, applies a bandage, and puts the limb in a cast or splint depending on the location and the type of fracture [33]. \begin{table}
\begin{tabular}{l l l l l l} \hline  & **Humerus Status/Monitoring Parameter** & **Normal** & \begin{tabular}{l} **Transverse** \\ **Factured** \\ \end{tabular} & \
\begin{tabular}{l} **30\({}^{\circ}\)****Oblique** \\ **Factured** \\ \end{tabular} &
\begin{tabular}{l} **60\({}^{\circ}\)****Oblique** \\ **Factured** \\ \end{tabular} \\ \hline \multirow{3}{*}{\(\Phi=90^{\circ}\)} & **Return loss dB** & \(-38.15\) & \(-15.8\) & \(-16.5\) & \(-15.5\) \\  & **Transmitted power density \(\mu\)W/m\({}^{2}\)** & \(1602\) & \(1417.6\) & \(1417\) & \(1354.4\) \\  & **\% Reduction** & & \(11.57\%\) & \(11.54\%\) & \(15.45\%\) \\ \(\Phi=-90^{\circ}\) & **Transmitted power density \(\mu\)W/m\({}^{2}\)** & \(1166\) & \(1027.5\) & \(1026.7\) & \(982.4\) \\  & **\% Reduction** & & \(11.87\%\) & \(11.95\%\) & \(15.75\%\) \\ \hline \end{tabular}
\end{table} 
Table 6: Comparison between transmitted APD for the normal and fractured humerus. Figure 11: (**a**) The model, (**b**) antennas and fixation plate, (**c**) medical splint, (**d**) the fractured bone, and (**e**) the set. In this study, we performed the same surgical operation on the selected model with the aid of a specialist. The experiment is based on measuring the reflection coefficient of the implanted antenna in cases of normal and fractured bone. Measurements were carried out in two phases. The first phase represents the model after bone healing completion. We opened the tissue at a length suitable to the dimension of the antenna and the depth was up to the bone. The antenna was implanted in the bone to muscle boundary. On the opposite side, the tissue was opened, and the plate was fixed. The opened tissue was then closed by surgical stitches. A medical splint was added to the model, and the reflection coefficient was measured. This step was repeated for both antennas. In the second phase, the bone was obliquely broken, and measurements were taken. Figure 12 shows the measurements in cases of normal and fractured bone using both antennas. Figure 12: _Cont._  
It was easier to implement and adjust the wire antenna's length to resonate at the operating frequency, while it was more difficult than the planar antenna to fix within the tissue. The measurements showed good agreement compared to the simulation results. Figure 13 shows a comparison between the results of simulation and measurement for planar and wire antenna. Figure 12: Measurements of return loss in cases of normal and fractured bone by using wire and planar half-wave dipole antennas. The simulated model was approximated as concentric cylinders of tissues around the humerus shaft, while the real model is not symmetric and there are three muscles, vanes, and blood suppliers around the bone shaft.